metallurgical microscope

MetallurgicalMicroscope

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• Metallurgical Microscope is the most important tool for the Metallurgist for observing a microstructure and studying various metals or alloys for their use in engineering applications.

• In contrast to biological microscopes ,this microscope uses the principal reflection of light,which will be due to polished or opaque specimen-surface.


Types of Metallurgical Microscope

• Optical microscope• Scanning electron microscope(SEM)• Transmission electron microscope(TEM)• Auger electron microscope


Microscope Vocabulary

•Magnification: increase of an object’s apparent size • Resolution: power to show

details clearly• Both are needed to see a clear

image


Ocular lensBody Tube

Revolving NosepieceArm

Objective Lens

StageStage Clips

Coarse adjustment knobFine adjustment knob

Base

DiaphragmLight


Ocular lens

magnifies; where you look through to see the image of your specimen.

They are usually 10X or 15X power. Our microscopes have an ocular lens power of 10x.


arm

supports the tube and connects it to the base


stage

the flat platform where you place your slides


coarse adjustment knob

moves stage (or body tube) up and down


base

the bottom of the microscope, used for support


body tube

connects the eyepiece to the objective lenses


revolving nosepiece

the part that holds two or more objective lenses

and can be rotated toeasily change power


objective lens

Adds to the magnificationUsually you will find 3 or 4 objective lenses on a microscope. They almost

always consist of 4X, 10X, 40X and 100X powers. When coupled with a 10X (most common)


objective lenses

The high power objective lenses are retractable (i.e. 40XR). This means that if they hit a slide, the end of the lens will push in (spring loaded) thereby protecting the lens and the slide.


stage clips

Stage clips hold the slides in place. If your microscope has a mechanical stage, you will be able to move the slide around by turning two knobs. One moves it left and right, the other moves it up and down.


diaphragm

controls the amount of light going through the specimen

Many microscopes have a rotating disk under the stage. This diaphragm has different sized holes and is used to vary the intensity and size of the cone of light


light

makes the specimen easier to see


Construction and Working

• A draw tube carrying eyepiece at its top end slides within the body tube of the Microscope with the help of a rack or pinion arrangement by rotating coarse or fine adjustment knobs.

• Sliding of draw tube within body tube allows varying distance between the eyepiece or objective thus helps focusing of the object.

• Fine adjustment knob helps final focusing of object.


• The objective located at bottom and of body tube structure of the metal specimen and the eyepiece enlarges the images formed by the objective.

• Eyepiece are available with different magnifying powder such as 5X,10X,15X,etc.,the powder being marked on them.

• The light source inside the side tube of microscope provides illumination for specimen.


• The light from the source passes through a collimating lens or a diaphragm in a controlled amount.

• The incident light from external light source falls on a plane glass reflector kept at 45 degree.

• The reflected light beam now passes through the objective or plane glass reflector to form the final image.


• The image created(any magnified by objective) is further magnified by eyepiece lens,the gross magnification being product of the magnification of the objective & eye-lens.

• The usual value of magnification for optical microscope is 2000X.


REFERENCE:-•BOOKS INDIA PUBLICATION•WIKIPEDIA


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metallurgical microscope

Engineering