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Operating InstructionsLFA 447TM

01/09 J:\LFA447\Contents.doc

Operating Instructions LFA 447

TM Nanoflash

Contents

Chapter I General Information

Chapter II Installation

Chapter III System Components

Chapter IV Operating the Instrument

Chapter V Appendix

01/09 J:\LFA447\CHAPTER1.DOC

Chapter I

General Information

LFA 447TM

General InformationLFA 447TM

01/09 J:\LFA447\CHAPTER1.DOC 1

Information

In the design of your instrument, we endeavor to take individual solutions into account and to include these in the documentation. However, in order to keep the scope of the technical documentation at a reasonable level, we must limit the description to a standard model. We ask for your understanding, if additional information particular to your instrument is not included within the scope of the standard instructions. This additional information can always be found on the corresponding information sheets.

Prior written permission from NETZSCH-Gerätebau GmbH is required

for electronic or mechanical duplication and distribution of these

instructions.

All technical data, instrument features and other information described

in these operating instructions are presented to the best of our

knowledge and in accordance with the technical standards of the

instrument at the time of printing.

We welcome any comments, suggestions or new ideas concerning the

instrument and these operating instructions. Please address them to:

NETZSCH-Gerätebau GmbH

Wittelsbacherstraße 42

D - 95100 SELB

Telephone: 09287/881- 0

Telefax: 09287/881- 144

E-Mail: [email protected]

Internet: http://www.netzsch-thermal-analysis.com

Maintenance and service must be carried out by NETZSCH Customer

Service personnel.

A service contract is available for our customers.

This instruction manual is provided to give the customer information

on proper operation of the instrument. NETZSCH-Gerätebau GmbH will

accept no liability for damage resulting from improper use.



Notes on the Use of this Manual

In this manual, the symbols described below are used to simplify orientation.

NOTE! This sets particularly important information apart from the rest of the text.

ATTENTION! These instructions must be followed exactly to avoid injury to the user and damage to the instrument.

This symbol refers to more detailed information which can be found elsewhere, e.g. in the Software Manual.

The tools listed after this symbol are required for the installation or modification of your instrument.



Basic Safety Information

State-of-the-Art Your instrument has been produced with state-of-the-art technology and is safe to operate.

Authorized Operation

Any operation of the instrument other than as authorized requires consultation with NETZSCH. Any use exceeding the (expanded) authorized operation is considered unauthorized. The manufacturer will not be liable for any damage resulting from such use.

Manufacturer's Requirements

Authorized operation of the instrument includes compliance with manufacturer's requirements regarding installation, commissioning, operation and maintenance.

Training of Personnel

Your instrument may only be operated and maintained by authorized, trained and individually instructed personnel who have been informed of possible sources of danger.

Responsibility Responsibility for commissioning, operation and maintenance must be clearly defined and compliance must be ensured. The resulting responsibilities can be clearly resolved under the aspect of safety.

Unauthorized Access The operator must make sure that only trained personnel work on the instrument.

Improper Operation Any type of operation which reduces the safety of the user and the operability of the instrument should be avoided.

Unauthorized Changes to the System

Unauthorized modifications and changes which effect the safety of the instrument are not permitted.

Obligation to Report

Changes to the

System

The user is obligated to immediately report to the operator in charge any changes to the instrument which effect the safety of the system.



Maintenance

Obligation

The operator of the system must ensure that the instrument is operated in perfect condition at all times.

Proper Set-up of the

Work Stations

The operator must guarantee the openness and cleanliness of the work stations at the instrument through appropriate instruction and inspections.

Shut-down For all maintenance work, the instrument must be switched off and unplugged.

Removal of

Protective Devices

Protective devices may only be removed when the instrument is switched off and unplugged. It is imperative that the protective devices be replaced before starting the instrument.

Checks following

Maintenance or

Repair Work

After maintenance or repair work, a check should be made to ensure that all protective devices are in place and operate properly. Only then should the instrument be started.

Industry-specific

Accident Prevention

Regulations

The operator must observe the relevant regulations and protective measures when handling the required gases. In addition, possible reactions with the materials used must be considered. At operating temperatures above 55°C, protective gloves must be worn. In any case, the industry-specific and local accident prevention regulations are also valid for the instrument.

Disposal of

Production Materials

Production materials are to be disposed of according to local regulations.

Maintenance or

Repair

Products sent in for maintenance or repair should, to the extent possible, be free of harmful substances (e.g. radioactive, toxic, caustic or microbiological materials). Otherwise, the type of contamination must be declared. Products not explicitly declared to be "free of harmful substances" will be decontaminated at the expense of the sender.



Operating

Instructions

Using the Operation Manual, the operator should prepare operating instructions which specify the actions and tasks required for safe operation. The operating instructions should be placed in a suitable location in the work place and complied with by the employees.

Gases Observe the relevant regulations and protective measures when handling the required gases. Consider possible reactions with the materials. Warning signs should be hung in the appropriate places in accordance with national and regional regulations.



Safety regulations for handling liquid nitrogen LN2

It is imperative that you observe the safety regulations for handling nitrogen.

FIRE AND EXPLOSION HAZARDS

Neither gaseous nor liquid nitrogen are flammable and do not in themselves constitute a fire or explosion risk. However, both gaseous and liquid nitrogen are normally stored under pressure and the storage vessels, whether gas containers or liquid tanks, should not be located in areas where there is a high risk of fire or where they may normally be exposed to excessive heat. Vessels containing compressed gaseous nitrogen may rupture violently if overheated as a result of exposure to fire.

Oil-lubricated compressors operated continuously on nitrogen supply for a prolonged period should not be switched to air supply without thorough cleaning. Otherwise there is a danger that unoxidized pyrophoric deposits which may have formed in the machine will explode violently on contact with compressed air.

At equal pressures, the boiling point of liquid nitrogen is lower than that of liquid air. Air will condense on the external surfaces of vessels or pipework containing liquid nitrogen at an equilibrium pressure less than 1.5 bars absolute if the vessels are either not lagged, or are lagged with a porous cellular-type insulator. The liquid air produced can result in oxygen enrichment of the atmosphere local to the equipment. Special precautions must therefore be taken with regard to the insulation of the vessel before any maintenance or repair work is started, particularly where the use of open flames or other potential sources of ignition is intended.

MATERIAL HAZARDS

Certain steels, such as carbon steel, and some other materials are unsuitable for use at sub-zero temperatures because they lose impact strength and become extremely brittle. Carbon steel cannot be used safely at temperatures below -30°C (-20°F) and is obviously unsuitable for use with liquid nitrogen. Materials normally suitable for use at low temperatures are the austenitic stainless steels, aluminum and copper and its alloys. In an area where liquid nitrogen spillage can occur, care should be taken to ensure that the liquid does not come into contact with vulnerable steel structures and vehicle tires.

Care should be taken to ensure that liquid nitrogen and cold nitrogen vapor are not trapped in a closed system without any form of automatic pressure relief. Otherwise, pressures well in excess of the equipment working pressure will be generated as the system warms up, thus creating a possible rupture hazard.



HEALTH HAZARDS

Asphyxia

Nitrogen, although non-toxic, can constitute an asphyxiation hazard through the displacement of the oxygen in the atmosphere. The potential for this type of hazard is significant because of the widespread use of nitrogen as a purging or blanketing gas in chemical, metallurgical, and other industrial operations and because neither nitrogen gas nor oxygen depletion are detectable by the normal human senses. Unless adequate precautions are taken, persons can be exposed to oxygen-deficient atmospheres if they enter equipment or areas which have contained or have been purged with nitrogen.

Oxygen is required to support life and its volume concentration in the atmosphere is normally 21%. At normal atmospheric pressure (760 mm Hg), persons may be exposed to oxygen concentrations of 18% by volume (equivalent to a partial pressure of 135 mm Hg), or even less, without adverse effects. However, the response of individuals to oxygen deprivation varies considerably. The minimum oxygen content of breathing atmosphere should be 18% by volume (at normal atmospheric pressure), but to ensure a wider margin of operational safety, it is recommended that persons not be exposed to atmospheres in which the oxygen concentration is, or may become, less than 20% by volume.

Symptoms of oxygen deprivation, such as increased pulse and breathing rate, fatigue and abnormal perceptions or responses, may be apparent at an oxygen concentration of 16%.

Permanent brain damage or death may result from breathing atmospheres containing less than 10% oxygen. Initial symptoms include nausea, vomiting and gasping respiration. Persons exposed to such atmospheres may be unable to help themselves or warn others of their predicament. The symptoms are an inadequate warning of the hazard.

BREATHING A PURE NITROGEN ATMOSPHERE WILL PRODUCE IMMEDIATE LOSS OF CONSCIOUSNESS AND ALMOST IMMEDIATE DEATH.

Cold burns

Liquid nitrogen and cold nitrogen vapors or gases can produce effects on the skin similar to a burn. Unprotected parts of the body coming into contact with uninsulated parts of the equipment may also stick fast (because all available moisture is frozen) and the flesh may be torn on separation.



Frostbite

Severe or prolonged exposure to cold nitrogen vapor and gas can cause frostbite. Local pain usually gives warning of freezing, but sometimes no pain is experienced. Frozen tissues are pain-free and appear waxy with a pallid yellowish color. Thawing of the frozen tissues can cause intense pain. Shock may also occur if the frostbite is at all extensive.

Effects of cold on lungs

Prolonged breathing of extremely cold atmospheres may damage the lungs.

Hypothermia

Low environmental temperatures can cause hypothermia and all persons at risk should wear warm clothing. Hypothermia is possible in any environmental temperature below 10°C (50°F), but susceptibility depends on time, temperature and the individual. Older persons are more likely to be affected. Individuals suffering from hypothermia may find their physical and mental reactions are adversely affected.



PRECAUTIONS

Operations and maintenance

It is essential that operations involving the use of gaseous or liquid nitrogen, particularly where large quantities are used, are conducted in well-ventilated areas to prevent the formation of oxygen-deficient atmospheres.

Ideally, nitrogen should be vented into the open air well away from areas frequented by personnel. Nitrogen should NEVER be released or vented in enclosed areas or buildings where the ventilation is inadequate.

Before entering areas, vessels or other equipment for maintenance or other purposes in which the atmosphere is, or may become deficient in oxygen, action should be taken to make the equipment safe. Preparatory work will include equipment isolation from hazardous processes, purging and continued ventilation with air as appropriate. Equipment in service with flammable gases should be purged with nitrogen prior to purging with air to avoid the formation of flammable mixtures. NEVER USE OXYGEN AS A SUBSTITUTE FOR AIR AS A PURGING MEDIUM. Prior to entry, the atmospheres should be tested with a portable oxygen analyzer (calibrated before use) to ensure that the oxygen lies between 20% and 22% by volume. The use of a safety work permit system is strongly recommended (Note: The latter two recommendations need not apply when entering a Cryo-Guard vehicle for normal loading or unloading purposes. For details see Cryo-Guard Drivers Instruction Manual).

It should be recognized that although nitrogen is slightly lighter than air at equal temperatures, liquid nitrogen and cold nitrogen vapor are denser than air and can accumulate in low-lying areas such as pits and trenches. Where large spills of liquid nitrogen occur, a fog is formed in the vicinity of the spill caused by the condensation of water vapor in the surrounding air. The fog, in addition to severely reducing visibility, may contain oxygen concentrations appreciably lower than those of air, thus presenting a local asphyxiation hazard.

IF IT IS NECESSARY FOR A PERSON TO ENTER AN OXYGEN-DEFICIENT ATMOSPHERE FOR MAINTENANCE OR OTHER PURPOSES, IT IS ESSENTIAL THAT HE/SHE WEAR, AND BE TRAINED IN THE USE OF, A SELF-CONTAINED BREATHING APPARATUS.

Persons entering an oxygen-deficient area are advised to wear a safety belt with a manned safety line attached. Standby personnel should have ready access to self-contained breathing apparatus should emergency assistance be required.



Personnel protection

It is recommended that persons handling gas containers wear safety glasses, safety footwear and clean, sturdy gloves.

Persons handling equipment in service with liquid nitrogen should wear protective face shields, loose fitting leather or insulated gauntlets.

EMERGENCIES

In the event of accident or emergency, the instructions below should be implemented without delay. After emergency action has been taken, contact your nearest Air Products PLC Sales Office (see list at the back) for further advice.

Asphyxiation

Persons showing symptoms of oxygen deprivation should be moved immediately to a normal atmosphere. Persons who are unconscious or not breathing must receive immediate first aid. Medical assistance should be summoned without delay and first aid measures include inspection of the victim's airway for obstruction, artificial respiration and simultaneous administration of oxygen. The victim should be kept warm and quiet.

It is important to note that personnel carrying out rescue operations must minimize the risk to themselves. A RESCUER SHOULD NOT ATTEMPT TO ENTER AN OXYGEN-DEFICIENT ATMOSPHERE WITHOUT USING SUITABLE SELF-CONTAINED BREATHING APPARATUS; OTHERWISE HE MAY HIMSELF BE OVERCOME. Many double fatalities have occurred in industry as a result of personnel who, with the best intentions but without proper breathing apparatus and equipment, have entered an oxygen-deficient atmosphere in an attempt to rescue a colleague.

Treatment of cold burns and frostbite

Cold burns should receive medical attention as quickly as possible. However, such injuries are not an everyday occurrence and doctors, hospital staff or on-site first aid personnel may not be aware of the basic methods of treatment. The following notes describe the first aid treatment and recommended advice for further treatment to be given by a medical practitioner or a hospital.

First Aid

In severe cases, summon medical attention at once. Flush affected areas of skin with copious quantities of tepid water to reduce freezing of tissue. Loosen any clothing that may restrict blood circulation. Move the victim to a warm place but not to a hot environment and do not apply direct heat to the affected areas. Every effort should be made to protect the frozen areas from infection and further injury. Dry, sterile bulky dressings may be used but should not be applied so tightly that blood circulation is restricted.



Treatment by medical practitioner or hospital

a) Remove any clothing that may constrict the circulation to the frozen area. Remove patient to sick bay or hospital. b) Immediately place the part of the body exposed to the cryogenic material in a water bath which has a temperature of not less than 40°C (104°F) but not more than 45°C (113°F). (See below for exceptions to this recommendation.) NEVER USE DRY HEAT OR HOT WATER. Temperatures in excess of 45°C will superimpose a burn upon the frozen tissue. c) If there has been massive exposure to the super-cooled material so that the general body temperature is lowered, the patient must be re-warmed gradually. Shock may occur during rewarming, especially if this is rapid. d) Frozen tissues are pain-free and appear waxy with a pallid yellowish color. They become painful, swollen and very prone to infection when thawed. Therefore, do not re-warm rapidly if the accident occurs in the field and the patient cannot be transported to a hospital immediately. Thawing may take from 15 to 60 minutes and should be continued until the blue, pale color of the skin turns to pink or red. Morphine or some other potent analgesic is required to control the pain during thawing and should be administered under professional medical supervision. e) If the frozen part of the body has thawed by the time medical attention has been obtained, do not re-warm. Under these circumstances, cover the area with dry sterile dressings with a large bulky protective covering. Administer a tetanus booster after hospitalization.

Hypothermia

Persons suspected to be suffering from hypothermia should be wrapped in blankets and moved to a warm place. Slow restoration of temperature is necessary and forms of locally applied heat should not be used. Summon medical attention.

Fire fighting

Nitrogen is not flammable and no special fire fighting precautions or equipment are needed. If an outbreak of fire occurs in the vicinity of nitrogen storage equipment, the local fire department should be summoned at once. Unless vessels containing compressed gaseous nitrogen can be removed safely to an unaffected area, every effort should be made to keep them cool by spraying them with large quantities of water.

Liquid nitrogen spillage

If large spills of liquid nitrogen occur, large quantities of water should be used to increase the rate of liquid vaporization.

Vehicles involved in a heavy liquid spillage should not be moved as the tires may be frozen to the ground and the rubber will be brittle.



GAS CONTAINERS

The content of the container is primarily identified by a label attached to the container shoulder and secondarily by the color of the container. The Air Products identification colors for containers containing nitrogen are: Body: French gray; shoulder and guard: black (BS 349: 1973)

The following practices are recommended for safe handling and storage of high-pressure gases including nitrogen containers.

General

− Only trained persons should handle compressed gases.

− Observe all regulations and local requirements regarding the storage of containers.

− Do not remove or deface labels provided by the supplier for the identification of the container contents.

− Ascertain the identity of the gas before using it.

− Know and understand the properties and hazards associated with each gas before using it.

− Establish and implement plans to cover any emergency situations that might arise.

− When doubt exists as to the correct handling procedure for a particular gas, contact the supplier.

Handling and Use

− Wear stout gloves.

− Never lift a container by the cap or guard unless the supplier states it is designed for that purpose.

− Use a trolley or other suitable device or technique for transporting heavy containers, even for a short distance.

− Leave valve protection caps or guards (where provided) in place until the container has been secured against a wall or bench or placed in a stand and is ready for use.

− Where necessary, wear suitable eye and face protection. The choice between safety glasses, chemical goggles, or full face shield will depend on the pressure and nature of the gas being used.



Storage and handling

− Where necessary for toxic gases, see that self-contained positive pressure breathing apparatus or a full face air line respirator is available in the vicinity of the working area.

− Check for gas leaks using a suitable method. Flammable and toxic gas monitors are available. Where a gas is toxic, check special procedures specified by the supplier.

− Ascertain that an adequate supply of water is available for first aid, fire fighting, or dilution of corrosive material in the event of leakage.

− Employ suitable pressure regulating devices on all containers when the gas is being emitted to systems with a lower pressure rating than that of the container.

− Before connecting the container for use, ensure that back feed from the system into the container is prevented.

− Ascertain that all electrical systems in the area are suitable for service with each gas.

− Never use direct flame or electrical heating devices to raise the pressure of a container. Containers should not be subjected to temperatures above 45°C.

− Never re-compress a gas or a gas mixture from a container without consulting the supplier.

− Never attempt to transfer gases from one container to another unless expressly agreed beforehand with the supplier.

− Do not attempt to increase liquid draw-off rate by pressurizing the container without first checking with the supplier.

− Do not use containers as rollers or supports, or for any other purpose than to contain the gas as supplied.

− Never permit oil, grease or other readily combustible substances to come into contact with valves of containers containing oxygen or other oxidants.

− Keep container valve outlets clean and free of contaminants, particularly oil and water.

− Do not subject containers to abnormal mechanical shocks which may cause damage to their valves or safety relief devices.

− Never attempt to repair or modify container valves or safety relief devices. Damaged valves should be reported immediately to the supplier.

− Close the container valve whenever gas is not required, even if container is still connected to equipment.



− Replace outlet caps or plugs and container caps (where provided) as soon as container is disconnected from equipment.

Storage

− Containers should be stored in a well-ventilated area. Some gases will require a specially built area.

− Store containers in a location free of fire risk and away from sources of heat and ignition. Designation as a "No smoking" area may be desirable.

− The storage area should be kept clear and access should be restricted to authorized personnel only. The area should be clearly marked as a storage area and appropriate hazard warning signs displayed (flammable, toxic, radio active etc.).

− Containers in storage should be properly secured to prevent toppling or rolling.

− Vertical storage is recommended where the container is so designed.

− Container valves should be tightly closed and, where appropriate, valve outlets should be capped or plugged.

− Container valve protection guard or cap should be in place and properly secured.

− Protect containers stored in the open against rusting and weather extremes. Containers should not be stored in conditions likely to encourage corrosion.

− Store full and empty containers separately and arrange full containers so that the oldest stock is used first.

− Gas containers should be segregated in the storage area according to the various categories (toxic, flammable, oxidant, etc.).

− The amounts of flammable or toxic gases in storage should be kept to a minimum.

− Flammable gases should be stored away from other combustible materials.

− Containers held in storage should be periodically checked for general condition and leakage.



LIQUID STORAGE CONTAINERS

− Liquid nitrogen is stored and transported either in purpose built storage tanks or dewar flasks. Storage quantities vary from a few liters for dewar flasks to several thousands of liters for storage tanks. The storage tanks are pressurized, insulated containers which are installed in accordance with established codes of practice. All liquid storage areas should be kept clean and free of flammable materials.

− Unlike a liquid nitrogen tank, a vaccum-jacketed dewar flask is essentially a non-pressurized container.

− Recommendations for handling and storage are as follows:

− The protective caps on dewar flask fill/ drain outlets should be kept closed when not in use to prevent contamination and ensure that blockage by frost does not occur. Check caps regularly to ensure that they have not become sealed by frost accumulating on the surface. Formation of frost may be removed by warming gently with air.

− DO NOT USE SOURCES OF EXCESSIVE HEAT SUCH AS STEAM OR OPEN FLAMES.

− Dewar flasks should be stored in well-ventilated areas where they are protected against weather extremes, particularly heavy rain.


Chapter II

Installation

LFA 447TM

InstallationLFA 447TM


Contents

INSTALLATION.............................................................................................1

PACKING AND DELIVERY ............................................................................1

LOCATION REQUIREMENTS ..........................................................................2

INSTALLATION SCHEMATICS.........................................................................3

CONNECTING THE COMPUTER SYSTEM ................................................................. 4

CONNECTING THE THERMOSTAT .......................................................................... 5



Installation

In most cases, your LFA 447 is set up and commissioned by one of our customer service engineers.

If you would like to set up your instrument yourself, please read the following sections.

Packing and Delivery

We deliver all components in separate cartons. The measuring unit, electronics, computer system etc. are packed in form-molded foam to protect against damage during transport.

� We recommend keeping the original cartons. Should repairs or an extension of the system become necessary, the cartons can be reused, thus ensuring a relatively safe return to the manufacturer.

� Prior to shipping, we carefully test all components of the system for mechanical and electrical operability.

� After unpacking, please check all delivered components for possible transport damage and compare the individual items against the delivery note supplied.

� Should an item be missing, please contact us immediately.



Location Requirements

� Select the optimal component arrangement for the space you have available.

The location of your instrument must meet the following requirements:

� constant temperature conditions (room temperature) to the

extent possible

� no direct sunlight on the instruments

� dust-free environment to the extent possible

measuring system

A stable, shock-absorbent table with a working surface of approx. 2 m x 1 m, is required for the measuring part (measuring part, computer, printer).

thermostat The thermostat cooling system requires 0.5 m x 0.5 m space. The cooling system should be placed beside the table.

ATTENTION! Ensure that the measuring part is protected against external agitation! Agitation during the measurement affects the sensor and influences the measuring results.

An installation schematic of the measuring system follows on the next page.



Installation schematic

on line sta te te mp I te mp II

LFA 447

NanoFlash

560

measuring part LFA 447230 V (115 V), 6 A

computerweight: 10.5 Kg

310depth 420

thermostat230 V (115 V), 10 A

printerweight: 12 Kg

wide range power pack100-240 V, 6 A

Option,or provided by the customer

monitorweight: 3.5 Kg

460

640

470 500

table

measures in “mm”

floor

520

depth 450 depth 500depth 610

Ln max. 2l/day2

Arrangement of the instruments which has proven to be practical.

Figure 1: Installation schematics



Connecting the system components

Connecting the computer system

WATER INLET

WATER OUTLET

serial port

PC

LFA 447 (rear)

sensorconnection

computerconnection(serial port)

power supply

Figure 2: connecting the computer system

For connecting the computer system, see also the technical documentation of the computer manufacturer.



Connecting the thermostat

thermostat (rear)

LFA 447 (rear)

water filter

ALARM

power supply

outlet inlet

WATER INLET

WATER OUTLET

waterinlet

wateroutlet

Figure 3: connecting the thermostat

Adjust the temperature of the thermostat 2°C - 3°C below room temperature (e.g. 23°C)!


Chapter III

System Components

LFA 447TM

System ComponentsLFA 447TM


Contents

MEASURING UNIT ........................................................................................1

DETAILS OF THE MEASURING UNIT ................................................................2

FRONT PANEL................................................................................................... 3

BACK PANEL .................................................................................................... 4

EXTRACTOR TOOL......................................................................................5

SAMPLE HOLDER.......................................................................................6

STANDARD SAMPLE HOLDERS ...................................................................7

ROUND SAMPLES ........................................................................................... 7

SQUARE SAMPLES........................................................................................... 7

SPECIAL SAMPLE HOLDERS .......................................................................8

• SAMPLE HOLDER FOR LAMINATED SAMPLES.................................................. 8

• IN-PLANE SAMPLE HOLDER ...................................................................... 10

• SAMPLE HOLDER FOR LIQUIDS .................................................................. 11

• SAMPLE HOLDER FOR POWDERY AND PASTY SAMPLES .................................. 17

• MATRIX SAMPLE HOLDER........................................................................ 23

THERMOSTAT .........................................................................................23



Measuring unit

®

height460

610

560

depth

width

Figure 1: LFA 447 measuring unit



Details of the measuring unit

IR detector

sample changer

heater

optical filter

reflector

xenonflash lamp

detector electronics

systemelectronics

lamppowersupply

Figure 2: details of the measuring unit

The LFA 447 Nanoflash is equipped with a furnace capable of operation from room temperature to 300°C. The system is equipped with a software-controlled automatic sample changer allowing measurement of up to 4 samples at the same time. The temperature rise on the back face of the sample is measured using an In-Sb detector. Data acquisition and evaluation are accomplished using a comprehensive 32-bit MS-Windows software package. Various analysis models are integrated in the software. The data can be corrected for finite pulse and heat loss effects (radial and facial).



Front panel

®

LFA 447

online status charged interlock

operating elements

hood

detector housing

Figure 3: front panel of the measuring unit

label function

online green LED lights up: instrument is switched on

status start the software - click on the Nanoflash™ icon:

the status light on the front panel lights up in a red, yellow, green sequence once communication is established

charged the function of this indicator has been reserved for future use

interlock push button: hood is released – LFA 447 can be opened



Back panel

WATER INLET

WATER OUTLET

1

2

3

4 5

6

7

8

9

Figure 4: back panel of the measuring unit

no. label function

1 6A, 240 V mains fuses

2 power switch power switch: instrument “on/off”

3 AC input power connection 230 (115) V

4 fan

5 detector amplifier signal connection to the detector 9

6 thermostat outlet connection: cooling water outlet

7 thermostat inlet connection: cooling water inlet

8 RS 232 computer interface connection

9 detector amplifier signal see no. 5



Extractor tool

knob handhold

clip

Figure 5: extractor tool

The extractor tool is used to open the individual components of the sample holder. Operating principle Fix the lower end of the extractor tool in the respective part of the sample holder (e.g. furnace lid, the two fixing bolts on the lower part of the extractor tool must be clamped into the holes of the furnace lid). The lid can be removed. By pressing the knob on the top of the extractor tool the lid is pushed from the extractor tool.

furnace lid furnace lid furnace lid

extractor tool

fixing bolts

holes

knob

Figure 6: operating principle extractor tool



Sample holder

Individual parts

furnace lid

mask

sample(round or square)

sample holder plate (round or square inserts)

sample tray

extractor tool

furnace

Figure 7: individual parts of the sample holder

The vertical installation of the flash lamp and the IR detector allows a very easy sample holder handling. The sample holder is moved via the software in a horizontally stable and therefore defined position. Once the detector has been moved to the center position (this is done by clicking on the corresponding button in the main window), the sample holder is directly accessible and can be inserted or removed easily. The sample tray holds the sample holder plate with the sample inside. The contact between sample and sample support plate is greatly minimized. The requirement of lowest possible heat loss from the sample has been fulfilled by minimizing the contact between sample support and sample.



Standard sample holders

The samples must be placed into the sample holder plate and covered by the corresponding mask.

round samples square samples

sample holder plate with mask - size 1 -

sample diameter10.0 mm

Ø 7.8 mm

masksample holder plate


edge length8.0 mm

Ø 5.0 mm




Ø 9.8 mm



edge length10.0 mm

Ø 7.8 mm




Ø 20.4 mm



edge length12.7 mm

Ø 9.8 mm




operating principle:

sample holder plate(round or square inserts)

sample(round or square)

mask

Figure 8: operating principle standard sample holder

Special sample holders

• Sample holder for laminated samples

The sample must be cut into single sample strips (A) (strips length: 12.7 mm), placed into the sample holder plate (B), affixed by the two fixing screws (C) and covered by the corresponding mask (D) (see Figure 9).

stripes length12.7 mm

Ø 9.8 mm



square sample

sample strip

sample strip

sample strips mask

fixing screws fixing screws

sample holder plate

A B C D

Figure 9: operating principle sample holder for laminated samples



In addition:

The sample holder for laminated samples can also be used for in-plane measurements (anisotropic samples). In order to achieve this, the sample must also be cut into single sample strips (E) (strips length: 12.7 mm) which must be turned by 90° (on their side) (F) so that the sample can be measured in a horizontal direction. The sample strips must be placed into the sample holder plate (G), affixed by the two fixing screws (H) and covered by the corresponding mask (I) (see Figure 10).

sample


sample strip

sample strips

mask

fixing screwsfixing screws

sample holder plate

E GF H

I

90°square sample

sample strip sample strip

Figure 10: operating principle sample holder for laminated samples for in-plane measurements



• In-plane sample holder (for measurements of a round sample in a horizontal direction)

The In-plane sample holder is designed so that the position for the energy input on the bottom side of the sample and the position for measuring the temperature increase on the top side of the sample (energy output) are located at different lateral positions. Thus the measured temperature increase of the sample shows the thermal diffusivity in a horizontal direction (in-plane). Please note that the application is limited to thin samples with a high conductivity. Therefore the sample holder for laminated samples is used in most cases. The prepared sample must be placed into the sample holder plate and covered by the corresponding mask.


Ø 13 mm

energy input

energy output

sample holder plate

sample

mask

vert

ical

dir

ect

ion

horizontal direction (in-plane)


sample holder plate

sample

mask

Figure 11: operating principle in-plane sample holder



• Sample holder for liquids

By using a special sample holder it is possible to analyze liquids with the LFA 447 instrument. When using the sample holder please pay attention to the following indications.

lid

crucible liquid sample

ringof stainless steel

Figure 12: sample holder for liquids

Preparing the sample holder

The bottom side of the crucible and the indentation on the top side of the lid must be coated with graphite spray as shown in Figure 13.

lid(coating)

crucible(bottom side, with coating)

ring ofstainless steel

Figure 13: coatings on the cover and crucible

If the upper edge of the lid is soiled when applying the graphite spray, it must be cleaned with alcohol.



Determination of the liquid level in the crucible

htotal

hsample

hlid

hcrucible

For measurements, the 3 layer model for determination of the thermal diffusivity of the liquid must be used. This means that the bottom thickness of the crucible h

crucible,

the liquid level hsample

and the thickness of the cover bottom hlid

must be precisely known. The thickness of the crucible bottom h

crucible and the lid bottom h

lid can be

measured with a micrometer screw. The liquid level hsample

is the difference between the total height of the sample holder h

total and the thickness of the crucible bottom

hcrucible

plus the cover bottom hlid

:

h

sample = h

total - h

lid - h

crucible

After the measurement, e.g. polymer melting, the total height of the sample holder should be remeasured. If the total height of the sample holder h

total has risen, the

liquid level has changed during the measurement. For an ideal measurement, the liquid level must be constant during the measurement.



Pour the liquid in the crucible

sample tray

sample holderplate Ø 12.7 mm

hole of the sample holder plate

shallow margin (1.6 mm)

(must show to the top)

• Insert the sample holder plate ∅ 12.7 mm into the sample tray such that the shallow margin (1.6 mm) faces upwards (see figure).

crucible

ring ofstainless steel

sample holderplate Ø 12.7 mm

• Place the crucible with the ring of stainless steel into the sample holder plate.



drop of liquid

pipette

• Insert a drop of the liquid into the crucible. The volume of the drop should be 50 -60 µl. By known density of the liquid sample it is possible to determine the volume via measurement of the sample mass. It is also possible to use a pipette.

Please pay attention to the indications for the filling level:

ideal liquid level

ok

excessive

Oil or hydrocarbons are often difficult to be placed inside a crucible. They form no pearl but creep along he crucible walls. This will cause higher deviations in the measuring results. The reason for this is the low surface tension. We recommend in such cases not to drip the sample in the crucible but to place the sample with the help of a pipette from the bottom to the lid. When the sample "hangs" at the lid, the lid can be placed on the crucible.

lid

• Put the lid onto the crucible and ensure that it is level.



extractor tool

furnace lid

• Put the furnace lid in the place.

A test measurement with water should yield the following result: a = 0.146 mm

2/s (at room temperature)

Example of a measurement:

Liquid sample holder 304 V / Long / 3500ms* Signal Ratio (empty/water) < 1/7 3 shots / calc. Range 2000ms: a_water_25°C = 0.148 mm²/s (Lit: 0.146 mm²/s; +1.4%) * A calculation range of max. 2000 ms is recommended for all liquids.



The figure (example for water) shows that the calculation range is reduced to 2000 ms. This is strongly recommended for all measurements with the sample holder for liquids due to the heat spreading in the container which influences the detector signal above 2000 ms. In dependence on the thermophysical properties of the sample it can be necessary to reduce the calculation range to a value between the maximum and 2000 ms.

-> Shots -> Set range for calculation -> Input values -> 2000 ms -> activate "all shots” -> OK



• Sample holder for powdery and pasty samples

By using a special sample holder it is possible to analyze powdery and pasty samples with the LFA 447 instrument. When using the sample holder please pay attention to the following indications.

lower support plate lid panupper support plate

Figure 14: sample holder for powdery and pasty samples

Sample preparation for non-transparent samples:

pan(bottom side)

graphite spary

cover plate

schematic:

pan(bottom side)

cover plate

• Turn the pan and place a cover plate (Ø approx. 10 mm) on the bottom side. Coat the bottom side with graphite spray so that only the edge is coated.

NOTE! Only the transparent edge of the pan must be coated with graphite spray in order to prevent radiation heat transfer through the sapphire parts.



graphite spary

lid(bottom side)

cover plate

schematic:

lid(bottom side)

cover plate

coat onlyhere

• Turn the lid and place a cover plate (Ø approx. 10 mm) in the center of the bottom side. Coat the bottom side with graphite spray so that only the edge of the lid (bottom side) is coated.

NOTE! Only the transparent edge of the lid must be coated with graphite spray in order to prevent radiation heat transfer through the sapphire parts.

coated lid(bottom side)

coated pan(bottom side)

• Wait some minutes until the coating is dried.

lower support plate coated pan

• Insert the coated pan into the lower support plate.



powder sample (non-transparent)

• Fill the powdery sample into the sample pan.

ATTENTION! The powdery sample should exceed slightly from the upper edge of the pan.

powder sample

pan

lid

• Place the lid onto the pan.

upper support plate

• Place the upper support plate as shown in the figure and fix it by means of the phillips screws.

• Check the thickness: The inner distance between pan and lid is approx. 1.5 mm. If the sample is not compressible, a higher sample thickness could result. Compare the thickness with and without sample.



Sample preparation for transparent samples:

pan (inside)

graphite spary

schematic:

pan(inside)

coat here

• Coat the base area inside of the pan with graphite spray.

NOTE! The complete area of the pan must always be coated with graphite spray in order to make sure that the energy will be absorbed on the inner side of the pan.

lid (bottom side)

schematic:

lid(bottom side)coat here

• Turn the lid and coat the complete bottom side of the lid with graphite spray.

NOTE! The complete area of the lid must always be coated with graphite spray in order to make sure that the temperature increase will be measured on the inner side (sample side) of the lid!



coated lid(bottom side)

coated pan(inside)

• Wait some minutes until the coating is dried.

powder sample (transparent)

• Insert the coated pan into the lower support plate.

ATTENTION! The powdery sample should exceed slightly from the upper edge of the pan.

powder sample

pan

lid

• Place the lid onto the pan.



upper support plate

• Place the upper support plate as shown in the figure and fix it by means of the phillips screws.

• Check the thickness: The inner distance between pan and lid is approx. 1.5 mm. If the sample is not compressible, a higher sample thickness could result. Compare the thickness with and without sample.

Additional information for the measurement:

• Select the highest voltage (304 V) for the flash lamp!

• Select pulse width Long!

• Use the single layer model!

• For analysis we recommend to use model Cowan!



• Matrix sample holder

The installation and operation are described in chapter 5 “Appendix”! Thermostat

A thermostat is required to operate the instrument. This handles thermostatic control of instrument components relevant to the measurement and cooling of the furnace system. The thermostat is connected to the thermostat (inlet-outlet) connections on the back panel of the measuring unit. Technical data for the thermostat can be found in the accompanying operating instructions.

See Operating Instructions – Thermostat!

Adjust the temperature of the thermostat 2°C - 3°C below room temperature (e.g. 23°C)!

01/09 J:\LFA447\CHAPTER4.doc

Chapter IV

Operating the Instrument

LFA 447TM

Operating the InstrumentLFA 447TM

01/09 J:\LFA447\CHAPTER4.doc

Contents

OPERATING THE INSTRUMENT ................................................................................ 1

PRINCIPLE ...................................................................................................... 1

PREPARING THE IR DETECTOR ............................................................................ 3

OPEN AND CLOSE THE MEASURING UNIT ............................................................... 4

SAMPLE PREPARATION ..................................................................................... 5

SAMPLE THICKNESS .................................................................................................. 5

SAMPLE COATING .................................................................................................... 6

TRANSPARENT MATERIAL ...................................................................................... 6

GRAPHITE COATING ............................................................................................. 6

SAMPLE MASS ........................................................................................................ 7

SAMPLE DENSITY ..................................................................................................... 7

CALIBRATION MATERIALS ................................................................................. 8

INSERT A SAMPLE ............................................................................................ 9

STARING A MEASUREMENT ............................................................................. 12

PROCEDURE FOR CP-DETERMINATION ................................................................ 20

RIGHT CHOICE OF THE REFERENCE SAMPLE ................................................................. 20

RIGHT CHOICE OF THE SAMPLE GEOMETRY ................................................................. 20

CORRECT COATING ................................................................................................ 20

OTHER CHECKS ..................................................................................................... 20

OPTICAL FILTERS ........................................................................................... 21


01/09 J:\LFA447\CHAPTER4.doc 1

Operating the instrument

Principle

IR-detector

xenon flash tube

filter wheel

sample

P.C.furnacepower

pulseformingnetwork

signalamplifier

software

printer

T

Tmax

Tmax

Figure 1: measuring principle LFA 447

The Nanoflash instrumentation can be used to measure the thermal diffusivity, specific heat and thermal conductivity of metals, graphite, coatings, composites, ceramics, polymers and other materials. The instrumentation includes sophisticated hardware and simple menu-driven software to provide fast, accurate, and safe measurements. The Nanoflash works to the flash method according international standards ASTM E-1461, DIM EN 821 and DIN 30905.

The temperature rise of the other side is measured as a function of time using an infrared detector. A typical curve is shown in Figure 2. The measurement of the thermal diffusivity a and specific heat c

p allows the calculation of the thermal conductivity λ, with an additional

measurement or knowledge of the bulk density ρ of the sample material as shown in equation (1).

λ(T) = a(T) ⋅ ρ(T) ⋅ cp(T) (1) where: T is the Temperature

λ is the thermal conductivity a is thermal diffusivity

ρ is the bulk density c

P is the specific heat



A mathematical analysis of the measured temperature/time function allows the determination of the thermal diffusivity a. This is carried out in the analysis software which includes different mathematical models for the respective application. The most simple model which is described here for understanding is the “adiabatic model”. A detailed description of all available analysing models is described in the help-system of the analysing software. For adiabatic conditions, a is determined by the equation

(2) where: a = temperature diffusivity in cm

2/s

l = thickness of the test piece in cm t

50 = time at 50% of the temperature increase,

measured a t the rear of the test piece in s The above described method replaces the troublesome measurement of thermal parameters-such as absolute temperature increase and/or heat quantity - with a more accurate, direct and fast measurement of time and relative temperature increase. The software permits both manual and fully automatic control of the experimental process and also the evaluation of measuring results. Additional integrated mathematical model functions enable thermal diffusivity and the thermal resistance between layered and sandwich test pieces to be calculated.

Temperature

Time

Figure 2: Temperature History Curve

50

2

1388.0t

la ⋅=



Preparing the IR detector

sensor cover

- Remove the detector cover from the top of the detector casing.

plug

- Remove the plug from the top of the detector casing.

funnel

- Insert the funnel into the free opening.



LN2 storage vessel

- Fill in approx. 200 ml liquid nitrogen.

Wear safety glasses!

After a few minutes the detector should be completely filled.

The detector cooling stabilizes after 5 minutes.

Open and close the measuring unit

• Press the interlock button and move the hood to the rear end position in order to

open the measuring unit.

• Press the interlock button and move the hood to the front end position in order to close the measuring unit.

®

hood

Figure 3: open and close the measuring unit



Sample Preparation

Sample Thickness

It is important to use a sample with flat and parallel faces in order to record an accurate value for the sample thickness. To determine the sample thickness:

1. Use a micrometer to measure the sample thickness to at least three significant figures.

2. Repeat the measurement at four different points on the sample.

3. Use the average of these five values as the thickness value for the test. The optimum sample thickness depends on the diffusivity (α) of the material. The selected measurement period should correspond to 10-12 half times and be between 10 and 200000 ms.

The thermal diffusivity should be estimated to calculate the minimum and maximum sample thickness. The table below indicates suggested thickness for different diffusivity values.

Diffusivity Suggested thickness

(mm)

low diffusivity

e.g. polymers

(0.001cm2/s)

1 to 1.5

medium diffusivity

e.g. ceramics

(0.05 cm2/s)

1.5 to 2

high diffusivity

e.g. copper

(1 cm2/s)

2 to 3

If you do not know the approximate diffusivity of the material, try testing two or three samples of different thickness (range 0.5 mm to 3mm).



Sample Coating

Transparent Material

The analysis of the flash diffusivity data requires that the energy be absorbed in the surface of the sample. It also requires that only the sample surface temperature is measured by the IR detector. Some materials are transparent at visible and near IR wavelengths of the Xenon flash. A sputter-coated metal film (typically gold) is used on both sides of the sample to minimize the radiation heat transfer within the sample and to prevent the detector from viewing temperature changes within the sample. The required film thickness is approximately 1000 Å, and can be controlled by the settings used during the coating process. As a guide, most unfilled polymers and many ceramics and glasses will require a metal film or graphite coating. A missing or insufficient coating shows a high temperature increase in the detector signal directly after the shot (spike).

Graphite Coating

The samples must always be coated with graphite (it is also necessary if a thin sputtered metal film is already existing) in order to enhance the absorption of laser energy and the emission of IR radiation to the detector. The graphite coating greatly increases the resulting signal-to-noise ratio especially when the surface is highly reflective. Also important for the determination of the specific heat is the uniform coating of both surfaces of sample and reference. The measuring conditions for sample and reference must be exactly the same.

The total coating thickness should be approximately 5 µm and in most cases negligible concerning heat transfer through the sample. The graphite coating is somewhat porous, so that too thin a layer will transmit energy and may cause specific heat errors due to differing bare surface properties of the samples. The coating can be also be damaged by high flash power. For thin layers with a high thermal conductivity (e.g. foils, films) the thickness of the graphite coating should be minimized. In this case test the sample with different coating thicknesses in order to eliminate the influence of the coating.

Note: It is recommended that the spray be applied in a hood with adequate air flow to prevent fumes from escaping!



to coat the samples:

1. Clean all samples with a suitable solvent (including the reference sample if it has been graphite coated previously) and lay them side by side (maintaining sample identification).

2. Shake the can and hold it approximately 10-12 inches from the samples.

3. Fully depress the valve aiming to one side of the row of samples for a short time (< 1s) to initiate the spray. Slowly sweep across the row of samples several times while maintaining a constant distance, applying one thin coat.

4. Wait approximately 2 minutes for the coat to be dry.

5. Repeat steps 2-4 three more times.

6. Turn the samples over, taking care that the coating on the sample faces will not be damaged.

7. Repeat steps 2-4 two or three times.

Sample Dimensions

• Thickness

• Diameter/Length

Sample Mass

The sample mass is used for the calculation of the density which is necessary for the determination of the thermal conductivity.

Sample Density

The bulk density of the sample (in g/cm3) must be measured for the following tests:

• specific heat

• thermal conductivity



Calibration materials

reference samples recommended max. temp. [°C]

coating

SRM8421 (electrolytic iron) 700°C sandblasting, no graphite above 400°C

SRM1461 (steel) 900°C sandblasting, no graphite above 400°C

SRM781 (molybdenum) 2000°C sandblasting, no graphite

PocoAXM (graphite) 2000°C graphite

Pyroceram (ceramics) 900°C graphite

Alumina (ceramics) 2000°C graphite

The reference samples are also used in laser flash apparatus up to 2000°C. A graphite coating up to 400°C is possible for all reference samples and therefore useable also for the LFA 447; usually the maximum temperature of a reference sample is defined in the provided tables of properties (cp, a …); with exception of ceramic reference samples inert atmosphere is necessary above 300°C.



Insert a sample

• Use the software to move the sample stage to the center position. This is done by clicking on the “change sample” button in the main window. Open the LFA 447 measuring unit. Therefore press the interlock button and move the hood to the rear end position (see Figure 4). The sample holder is located below the detector housing.

®

hoodsample holder device

Figure 4: open the measuring unit

• Use the extractor tool as shown in Figure 5 to remove the furnace lid. Place the furnace lid on the scratch plate on top of the instrument. The furnace lid and sample holder may be hot. Placing them on the scratch plate prevents damage to benches or other items.

extractor tool

scratch plate

furnace lid

Figure 5: remove the cover from the sample tray



• Place the sample holder plates (round or square) into the sample tray and insert the

samples (round or square, as shown in Figure 6 and Figure 7) with corresponding mask. The sample tray can also be moved (removed or installed) by means of the extractor tool.

sample holder plates(round or square inserts)

sample tray

Figure 6: put in the sample holder plates

samples(round or square)

masks

Figure 7: insert the samples

The operating principle of the different sample holder is described in chapter 3 of this manual.



The Nanoflash sample tray has four positions. Figure 8 shows the sample tray with each individual sample position numbered 1 through 4.

1 2

3 4

sample 1

sample 3

sample 2

sample 4

Figure 8: sample positions

• Reinstall the cover by means of the extractor tool and close the measuring unit.

extractor tool

furnace lid

Figure 9: reinstall the furnace lid

Please make sure that all windows are cleaned!



Staring a measurement

1. After software installation, please insert the sample(s) and check the

hardware settings: >File>Instrument Configuration



2. Check measurement parameters

>Measurement>Parameters Please use for first measurements 270V, medium and always 300 points for baseline • A reason to increase the flash lamp power (>270 V, long pulse) is a bad signal-to-noise

ratio (maybe 8V signal increase and 4V noise)

• A reason to decrease the flash lamp power (<270 V, short pulse) is e.g. a signal overflow

at room temperature using a gain value of 1260 and lower -> especially at thin samples (= low mass) or samples with a low specific heat the energy must be decreased (to prevent the heating of sample of a few Kelvin which leads to wrong diffusivity values).

Usually, the negative influence of signal noise is smaller than the influence of too much energy. Due to more noise a little bit higher standard deviation can be expected, but the mean value of 5 shots is the same.



3. Define samples

press corresponding windows or >Samples>Define Sample>1…4

- Choose sample holder, sample name, ID

- possible types of measurement: • Single Layer: standard, please enter material, thickness and properties (properties can be

changed later after the measurement)

• Double Layer: for 2-layer systems, to measure thermal diffusivity of one unknown layer or to measure contact resistance between two layers (thermal diffusivity of both layers should be known); please enter data for each layer (with the exception of the thickness, all data can be changed later)

• Triple Layer: for 3-layer systems, to measure thermal diffusivity of one unknown layer; please enter data for each layer (with the exception of the thickness, all data can be changed later)

• In-Plane: for measurements with the special in-plane sample holder; in addition please

enter the diameters of the sample holder (diameter 1), and of the sample mask (diameter 2 and 3)



4. Press button “Add shots” (green “+” symbol)

Select a sample (1 to 4); enter the temperature of the first shot; enter the number of steps if you want to measure at different temperatures; enter the temperature between two steps (Inc.); enter the number of shots at each temperature (usually 5 or 6); to increase the temperature stability the time between two shots can be increased (time in seconds; in many cases not necessary); press the button “Add shot” right of the button field



5. Prior to starting a measurement, it is necessary to change the gain and duration for each

sample at each temperature manually (up to software version 0.96c); please consider that the maximum increase should be between 2 and 8 Volts – check this after the first shot, maybe the following gain values can be used:

25 C -> 5012 100°C -> 623 200°C -> 315 300°C -> 155

These values are only a rough estimation and can differ depending on the sample dimension and thermophysical properties; above 10 Volts, an overflow will be expected and the gain value must be decreased

10 halftimes should be used for the duration time. For this, the maximum temperature rise should be approx. at 2/5 of the total horizontal area displayed in the measurement window; the duration can also be checked during the analysis (>Shot>Set range for calculation>10 Halftimes; see below)

Duration time is too long!



Duration time is too short!

Duration time is ok (maximum at 2/5 of total x-range)!



6. Steps to import an LFA measurement file into analysis

- Create a new database: >Database>Create new empty - furthermore: >Database>Explore> ---new window is opened--- >Database>Import LFA 447 File ---please select correct directory--- c:\ngbwin\ta\nanoflash\files

Double click on the newest file (check the date of files) After this, you have to confirm the following questions with "yes"; the last measurement should now be visible in the database window > with a double click on the measurement, these will be loaded into the analysis

>Measurement>Recalculate diffusivity ---please use Cowan model--- (you can obtain further information on the models from the help menu)

after calculation, the results are visible; please check the duration time >Shot>Set range for calculation>10 Halftimes The use of 10 halftimes is recommended! A comparison of measurements using different duration times –maybe 2, 10 and 20 halftimes- shows different results, to study the influence please check this!



Procedure for cp-determination

The determination of the specific heat using LFA 447 occurs via the comparison method. Exactly the same test conditions for sample and reference are absolutely necessary. Please note the following indications:

Right choice of the reference sample

- Reference samples are offered for each material group: metals (e.g. SRM1461); polymers, ceramics (e.g. Pyroceram); C-composites (Poco graphite).

- Sample and reference should show similarly the same surface structure.

Right choice of the sample geometry

- Ideally the dimensions of the sample and reference should be equal → different dimensions are offered for all reference samples.

- Different diameter or edge lengths do mostly not cause an negative effect on the measuring results as long as the whole bottom side of the sample is lighted and the same aperture diameter is used (the aperture diameter must always be smaller than the diameter of the sample plate, ratio 0.7 to 0.8).

- Increase variations result if the thickness of the sample and reference is strong different, But: important is the distance between the surface of the sample and IR-detector, viz: through balancing of the difference of level good measuring results can be achieved, it is recommended to balancing the difference of level from thickness differences of more than 0.5 mm.

Correct coating

- The coating with graphite spray is used on the one hand for an increase of the emission ratio and the absorptance of the samples so that the signal-to-noise ratio is improved and otherwise to a homogenization of the surface (similar and homogenize energy input for sample and reference).

- Coat 2 to 3 thin layers (Shake the can and hold it approximately 30 cm from the samples), clean the sample with alcohol – This must be done before each measurement!

Other checks

- Check if the windows are clean before each measurement (Borofloat-glass between furnace and flash lamp as well as the 4 sapphire windows of the furnace lid).

- Check that nothing stands between the flash lamp and the sample (connecting cable or similar, especial for sample position 1 and 3), if necessary remove the front cover, take out the Borofloat-glass, loose the cable connection and correct the position.



Optical filters

The filter wheel has eight total positions. Positions 1 through 4 contain filters which can be rotated into the path of the flashtube to reduce the power. The various flashtube powers are available as follows:

Optional Neutral Density Filter(s) %light (transmission)

Position 1 0%

Position 2 25%

Position 3 50%

Position 4 75%

Position 5 100%

Position 6 100%

Position 7 100%

Position 8 100%

The choice of flash power depends mainly on the thickness or heat capacity (product of mass and specific heat) of the sample. Samples with a high heat capacity (product of mass and specific heat) require more energy than samples with a low heat capacity. If with the lowest possible energy (e.g. used for thin films: 190 V flash lamp voltage, short pulse) no useful measuring results are achieved, it is recommended to use the filter to reduce the power.


Chapter V

Appendix

LFA 447TM

AppendixLFA 447TM


Contents

TECHNICAL DATA .........................................................................................1

MATRIX SAMPLE HOLDER ..............................................................................2

INDIVIDUAL PARTS ............................................................................................... 2

INSTALLATION ..................................................................................................... 3

START A MEASUREMENT ..................................................................................... 13

LITERATURE .............................................................................................. 15

AppendixLFA 447TM


Technical data

Standard Sample Area

Dimensions: round samples: 25.4 mm, 12.7 mm, 10 mm

square samples: 12.7 mm, 10 mm, 8 mm

Sample Thickness: typically 1-3 mm

Temperature Range

ambient to 300°C (matrix sample holder: only room temperature)

Thermal Diffusivity Range

0.001 cm2/s to 10 cm

2/s

Flash lamp

Illumination: Xenon flash lamp

Wavelength: 150 nm - 2000 nm

Pulse Energy: 10 J/pulse, (adjustable power)

Pulse Width: approx. 100 µs, 250 µs and 450 µs

Sensor Type

InSb IR detector with integral dewar for LN2 cooling

Power supply

115 V to 240 V, 50 – 60 Hz

Dimensions in mm (w x d x h) / Weight (net) in kg

610 x 560 x 430 / 18

Technical data subject to change

AppendixLFA 447TM


Matrix sample holder

The matrix sample holder is used for the pointwise scanning of a sample. The individual parts and the installation is described below.

Individual parts

sample holder plate

A

B CD

E

FGH

coordinates plate

adjusting plate

casing

aperture support apertures withfixing screws (phillips screws)

allen key

support plate

Figure 1: Matrix sample holder – indiviadual parts

A

casing

B support plate

C sample holder plate

D coordinates plate

E allen key

F adjusting plate

G apertures (diameter: 1 mm, 2mm, 3.5 mm, 5 mm (with phillips screws)

H aperture support

AppendixLFA 447TM


Installation

1. Select Set Any Position to place the sample holder in the position for changing the sample holder.

2. Close the measuring software.

on/off switch

3. Switch off the LFA measuring unit on the rear of the instrument.

cap

4. Remove the cap (lift it upwards).

plug

hood

5. Disconnect the plug on the rear of the hood.

AppendixLFA 447TM


phillips screws

6. Loosen the phillips screws.

hood

7. Remove the hood (lift it upwards).

front cover

front cover

phillips screws

plug connection

8. Loosen the phillips screws, remove the front cover and disconnect the plug of the operating elements on the board as shown in the figure.

AppendixLFA 447TM


slide unit

9. Move the slide unit in the rear position.

cover plate

10. Remove the cover plate.

sample tray

11. Remove the sample tray.

plug connection

sensor

12. Disconnect the plug connection of the sensor.

AppendixLFA 447TM


sensor

13. Remove the sensor (lift it upwards).

G

H aperture support phillips screws

aperture

14. Insert an aperture into the aperture support and fix it with the phillips screws.

Apertures with different aperture diameter are available: 1 mm, 2 mm, 3.5 mm, 5 mm.

Apertures with a small aperture diameter allow a higher lateral resolution than apertures with a large diameter. In each case the amplification must be adjusted.

H aperture support

sensor

15. Screw the aperture support in the bottom of the sensor as shown in the figure.

AppendixLFA 447TM


sensor (upper position)

1

2

16. Insert the sensor and connect the plug.

ATTENTION!

When using the Matrix sample holder, the sensor must be placed in the upper position contrary to the normal sample holder. Lift the sensor from the normal position upwards and turn it counterclockwise until it snaps into the upper end position.

(In the normal sensor position, the guide pins go through the holes in the sensor support. If the sensor is placed in upper position, the guide pins must snap into the sensor support.)

guide pins

plug connection

thermocouple

furnace

a

b

a

b

17. Disconnect the plug connection: (only for 300°C furnace)

a – thermocouple b – furnace

cable run

18. Remove the cable from the cable run.

AppendixLFA 447TM


glass plate

19. Remove the glass plate (move it outwards).

phillips screws

20. Loosen the phillips screws.

rear left corner

furnace

21. Remove the furnace (lift it upwards). (for reassembly of the 300°C furnace: insert the furnace so that the furnace cable is placed in the rear left corner)

A casing slot

22. Insert the casing of the matrix sample holder so that the slot for the glass plate shows to the front.

AppendixLFA 447TM


phillips screws

23. Fix the frame with the phillips screws.

glass plate

24. Insert the glass plate.

B support plate

25. Insert the support plate.

BC sample holderplate

support plate

26. Put the sample holder plate (C) into the support plate (B) (position is not important).

AppendixLFA 447TM


front cover

front cover

phillips screws

plug connection

27. Connect the plug connection of the control elements, push the front cover onto the instrument and fix it with the phillips screws.

hood

28. Push the hood onto the instrument.

plug

hood

29. Connect the plug on the rear of the hood.

AppendixLFA 447TM


phillips screws

30. Affix the hood with the phillips screws.

ATTENTION! When fixing the hood check that there is a small gap of approx. 2-3 mm between instrument cover and hood. Danger of scratching when moving the slide unit!

cap

31. Push the cap onto the instrument.

on/off switch

32. Switch on the instrument on the rear.

33. Start the measurement software.

34. Matrix Sample must be selected in the instrument configuration:

Menu: File

Menu item: Instrument Configuration Sample Tray → Matrix Sample

AppendixLFA 447TM


Reassembly to the 300°C-furnace

The reassembly to the 300°C furnace with four samples must be carried out in reverse order.

ATTENTION!

• sensor:

sensor

guide pins

For the 300°C furnace the sensor must be placed in the lower position so that the guide pins go through the holes in the sensor plate as shown in the figure.

• Software settings:

software settings for the 300°C furnace:

- The standard sample holder with Four Samples must be selected in the instrument configuration:

Menu: File Menu item: Instrument Configuration

Sample Tray → Four Samples

- The furnace type 300 must be selected in the instrument configuration:

Menu: File Menu item: Instrument Configuration

Furnace Type → 300

AppendixLFA 447TM


Start a measurement

C

sample

sample holder plate

• Put the sample on the sample holder plate.

F adjusting plate

sample

• Check that the height of the sample is not higher than the lower edge of the adjusting plate.

• If not: The height of the support frame can be adjusted by means of the lifting screws (with the allen key (E)) so that the support frame is raised or lowered.

B support frame

lifting screws

AppendixLFA 447TM


coordinate plate

• Before starting a measurement, insert the coordinate plate where you can see the values for x and y position (in "mm") which have to be entered into the measuring software.

0

0

10

10

20

-10

-10

20-20

-20

x

yPosition (x/y) in “mm”

top view coordinate plate

• After this, remove the coordinate plate.

• Enter the x/y-values for the desired measuring positions in the measurement software.

• Start the measurement.

AppendixLFA 447TM


Literature

(1) "Flash Method of Determining Thermal Diffusivity, Heat Capacity, and Thermal Conductivity", Parker et al, J. Applied Physics 32, 1679 (1961).

(2) "Pulse Method of Measuring Thermal Diffusivity at High Temperatures", Cowan, J. Applied Physics 34, 926 (1963).

(3) "Radiation Loss in the Flash Method for Thermal Diffusivity", Clark and Taylor, J. Applied Physics, 46, 714 (1975).

(4) "Improved Data Reduction Methods for Laser Pulse Diffusivity Determination with the Use of Minicomputers", Koski, Proc. of the Eighth Symp. on Thermophysical Properties, Volume II, 94 (1981).

(5) "Une Nouvelle Technique d'Identification de la Diffusivite Thermique pour la Methode Flash", Degiovanni, Revue Phys. Appl. 21, 229-237 (1986).

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