Rust-free and long-lasting by functional coatings

S. Goedicke, F. Groß, G. Frenzer, S. Sepeur NANO-X GmbH

Automotive Coatings Berlin Nov. 25th 2011

Protective Coatings September 13th Düsseldorf

Overview Protective Coatings

Sol-Gel-Process or SiliXan®

Binder Use of transparent

binder solution

Coating formulation with functional pigments, particles, fillers etc.

The sol-gel process

Si

R

OR OR RO

Hydrolysis

+ H2O Si

R

HO

HO

Si

R

OH

OH

O - H2O

Condensation

Si

R

OH OH HO

nano condensates in solution

Further crosslinking after application to substrate

Evaporation of solvent and final crosslinking

- Si-O-Si = glass-like inorganic network

- R = OH or functional group

The sol-gel process

- Modification of nano particles, different function depending on type of particle, e.g. SiO2, TiO2, Al2O3, AlO(OH), CeO2, ZnO, ZrO2, Fe2O3

Example SiO2: Glass-like inorganic matrix and structuring by electrostatically stabilized nano particles

- Moiety R = Network modifier, e.g. methyl, propyl, phenyl, dimethyl... Flexibilisation of the inorganic network by targeted integration of „defects“.

- Moiety R = Network creator, organic moieties with functional groups such as epoxy, methacryl, isocyanato, amino... Creation of an additional organic network

Me

Me

Me

Me

O

O

O

Me

Me

O

Me

O

OH

HO HO

R Si

OH

OH

O

O

Stable Sol-Gel-Matrices Binders and their properties

Modification

Solubility Alcohols, glycol ether, esters, ketones

Alcohols, esters, ketones Water, alcohols

Stabilization Dilution Precipitation

Precipitation* Dilution, Additives (e.g. pigments)

Properties Glass-like, brittle, heat resistant

Scratch resistant, flexible Good adhesion on metals

Application Temperature-resistant coatings

Scratch resistant UV coatings

Corrosion protection

Sol-gel materials with shelf life between several months up to more than two years are obtained due to optimized production procedures *Worldwide patent WO 2002050191

CH3 O

O

O O

Binders and curing mechanism

• Lewis acids (AlOH, ZrOH …)

Activation temperature RT-80°C

• Acids / bases

Activation temperature: > 100°C

Innovation: Direct water-free curing of high-molecular silanes is possible

x

C

H

H

SiRO

RO

N C

O

O

y

C

H

H

x

C

H

H

NC

O

O ORSi

OR

OR

H HRO

x

C

H

H

SiRO

RO

N C

O

O

y

C

H

H

x

C

H

H

NC

O

O ORSi

OR

OR

H HRO

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

SiO2

Resins and catalysts available from:

x-protect® products

Product overview Corrosion protection for stainless steel,

aluminium, zinc galvanized steel

Coil coating for aluminium

- Anticorrosion coating for aluminium and highly polished aluminium - Coil coating application, PMT 200 - 250˚C, 1 min - Good adhesion without pretreatment - High transparency - Very good corrosion protection - Flexible, suitable for forming and punching

Aluminium after 1000 h salt spray test

coated uncoated

High transparent corrosion protection

Chemical resistant coatings

Protection for anodized aluminium

Anodized aluminium part coated with 5 µm transparent x-protect® coating after dipping in acidic (pH 1) and alkaline (pH 13.5) solution 15 min each at 40˚C, against uncoated reference

- Solvent and water based coatings based on sol-gel and SiliXan® binders - Spray or dip coating - Thermal curing at 130˚C - Good optical appearance - Abrasion resistant - Resistant against acidic (pH < 1) and alkaline cleaners (pH > 13)

Metallsubstrat

Unsichtbare Belegung vonMetalloberflächendurch Nanopartikel

Keine Anlaufspurendurch Fingerprints

No tarnish by fingerprints

Invisible layer of nanoparticles metal substrate

Antifingerprint coating For brushed stainless steel

• Strong reduction of the visibility of fingerprints

• Prevention of the blue tarnishing of the stainless surface (corrosion/oxidation by salts and organic acids from finger sweat)

• Easy and remainderless removal of the fingerprints with a dry cloth

• Suited for structured surfaces (e.g. brushed), unsuited for high polished surfaces

• Very thin transparent coating (0.5 – 4.0 µ)

• High abrasion resistance

• Good chemical resistance

• Conservation of the metal appearance

Reference Reference for spray coating

Spray cabinet with 4 spraying guns

Stainless steel dishwasher panels

InoxPlus®

Stainless steel outdoor lamps

Sanitary equipment

• Blanking, cutting, lasing

• Forming by bending, deep-drawing or rolling

• Joining technology: Welding, brazing, gluing

• Finishing by brushing, grinding or polishing

Requirements for Coil Coating Coilcoating

Household appliances

Exhaust hood

Washing machine

Oven Source: BSH

Forming and welding of stainless steel

Cross Cut Test

Crockmeter Test

Protection of stainless steel

Anti tarnish coatings

VP CA 1499 on stainless steel 1.4301 (AISI 304)

Stainless steel after 1h at 600˚C

• High temperature resistant coating for stainless steel

• Protection against tarnish (discoloration) at temperatures up to 600 °C

• Transparent → almost unaltered high-gloss appearance of stainless steel

• Application via dip-coating or spray-coating

Flexibility of Coating

After metal forming

Forming tool

Heat treatment 1h at 500°C after forming

Result: • Good layer adhesion after forming process • Very good tarnish protection also after forming

Tarnish Protection Properties

Protection of zinc and zinc-nickel galvanized steel and cast iron parts

Sealing for Zn and ZnNi

ZnNi galvanized steel sheet with 2 µm sol-gel coating after 720 h neutral salt spray test (DIN EN ISO 9227) against uncoated reference

- Water-based sealings for Zn and ZnNi galvanized parts - Spray or dip coating - Curing at 130˚C - Resistant against acidic (pH < 1) and alkaline cleaners (pH > 13)

Product overview x-tec® and x-tec® eco

Active corrosion protection for steel and cast iron

Titanid Active Corrosion Protection

Metal particles with Nano-TiOx passivation

SEM cross section of TiOx-modified Al-particles, TiOx layer thickness approx. 100 – 200 nm

Al

TiOx

5 µm

Titanid principle Passivation of discrete metal pigments without loss of electric conductivity Combination of aluminium, magnesium or zinc pigments possible Nano TiOx coating on the pigment Cathodic corrosion protection for steel and significant reduction of white rust formation

Titanid (Zn) on 22MnB5 steel compared to uncoated steel sheet and zinc-galvanized steel sheet with same coating thickness after salt spray test SST (ISO 9227)

Uncoated (22MnB5)

Electrogalvanized (7 µm Zn) on steel

NXACP-Zn coating (22MnB5) in 7 µm

1000 h salt spray 125 h SST > 1.000 h SST

Potential measurement of TITANID (Zn) on 22MnB5 in 3% NaCl solution

-0,9

-0,8

-0,7

-0,6

-0,5

-0,4

-0,3

-0,2

-0,1

0

0 20 40 60 80 100

t [h]

E [V

]

t [h]

E [V

]

Constant potential of -0.8 V

- No corrosion on steel sheet after > 1.000 h salt spray test - Considerably less „white rust“ as compared to electrogalvanized or HDG - Electrochemical potential of -0.8 V proves cathodic corrosion protection

Titanid Active Corrosion Protection

Titanid Active Corrosion Protection

• First Titanid serial product commercially available since September 2009 • MULTI ZINC from Würth (www.wuerth.com), new product name PROMAX • Room temperature curing zinc aerosol spray with cathodic corrosion protection • More than 500 h salt spray test with 15-20 µm coating thickness, worldwide unique performance • Bright silvery appearance

NXACP-Zn

Ideas for applications

Further applications

Corrosion protection for offshore wind power stations, industrial tubes, small parts like screws and bolts, cast iron parts, ...

Water-based formulation x-tec® eco Tailoring of sol-gel binders for anti corrosion coatings

Tailoring of binders with links to - inorganic or metallic substrates - fillers or functional particles, e.g. metals

Si

R

OR OR RO

Hydrolysis

+ H2O Si

R

OH OH HO

Si

R

HO Si

R

OH

OH

O - H2O

condensation

O surface modification

HO

Organic crosslinking

Inorganic condensation

Structuring by SiO2-particles

SiO2

-> Development of a water based sol-gel binder - With good anticorrosion properties - With low curing temperature - Suitable for bonding of metal pigments

Coating Formulation Basic optimization

Formulation of coating materials consisting of a water based binder, zinc and aluminium pigments and additives Optimization of - Appearance - Low curing temperature - Corrosion protection - Processability - Pot life -> Products x-tec® eco 4042 and x-tec® eco 4047

x-tec® eco on brake discs Coating of different types of brake discs

High-grade appearance and homogeneous coating thickness by automatic spray coating process

Cast iron brake disc coated with x-tec® eco 4042

Alternative brake disc types, lightweight construction disc partly coated

Corrosion test Neutral salt spray test (NSS) according to DIN EN ISO 9227

- No red rust after 120 h salt spray test - Up to > 400 h salt spray test possible on brake disc, more than 1000 h on steel sheet - “Absolute” resistance against rim cleaners by use of additional topcoat x-tec® eco top !

- After 120 h NSS test After 300 h NSS test

x-tec® eco black is a water based anticorrosion coating for brake discs with an attractive anthracite appearance. Properties: •Curing temperature: Roomtemp. -250˚C (RT-482˚F) • Temperature resistance: > 300˚C (482˚F) • Coating thickness: 5 – 30 µm • Salt spray test (DIN EN ISO 9227): up to 500 h (depending on geometry and coating thickness) • Application: Preferably spray coating. Dip and flow coating possible. • Free from chromium • Suitable for all functional surface areas including friction ring and flange

x-tec® eco black

Zinc flake, water based, black

x-tec® eco black

x-tec® eco black after 480 h salt spray test on cast iron part

480 h

Salt spray test DIN EN ISO 9227, 5% NaCl solution, 35°C

Linear taber with CS 17 friction pad, 550g load

x-tec® eco black on cast iron, after 200 double strokes

x-tec® eco black

Example of use – Cast iron tubes

State of the art anticorrosion coatings for pipelines: -2K polyurethane coating, 2-3 mm thickness -Epoxy coating 300..500 µm thickness -two or three layer systems - No black water based active corrosion protection available before x-tec® eco black

NANO-X GmbH Theodor-Heuss-Str. 11a 66130 Saarbrücken GERMANY Phone +49 (0)681-95940-0 Fax +49 (0)681-95940-15 E-Mail info@nano-x.de Web www.nano-x.de Contact: Dr. Stefan Goedicke Phone +49 (0)681-95940-21 E-Mail goedicke@nano-x.de

NANO-X GmbH Saarbrücken

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