conversion coatings 04.09

General Metal Finishing

Corrosion Resistant CoatingsFrom Clear to Iridescent From Automotive to Zinc Die Cast

Technology for Tomorrow’s Solutions

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With the ban of Cr(VI)-containing post-treatment for zinc and zinc alloy surfaces by the European legislation it was necessary to come up with a complete range of Cr(VI)-free products to cope with a diversity of requirements. This brochure gives an overview of Atotech’s leading Cr(III)-based alternatives from blue to iridescent finishes on all zinc and zinc alloy surfaces.

Formation of Chromate and Passivate Coatings

Atotech Conversion Coatings –Functional, Appealing, worldwide Recognized

Cr(VI) Chromate Cr(III) Passivate

Chromate conversion coatings in general develop on zinc surfaces in acidic hexa-valent chromium solutions by reduction of chromium(VI) to chromium(III).

For example:

Cr2O72- + 3 Zn + 14 H3O+ 2 Cr3+ +

21 H2O + 3 Zn2+

Due to the consumption of H3O+ ions the pH rises directly on the zinc surface. In the more alkaline environment the generated chromium(III) forms polynuclear complexes. On the surface of these chromium complex layers chromium(VI) compounds from the solution are adsorbed.

In trivalent chromium passivates the role of the oxidation agent is for example carried by nitrate, which is reduced.

For example:

NO3- + Zn + 2 H3O+ NO2

- + Zn2+ + 3 H2O

This process also consumes H3O+ ions the-refore contributes to a similar pH effect as with hexavalent chromates. The outcome is that the soluble chromium(III) compounds in passivates hydrolyze and build up a similar conversion layer on the zinc surface.

CrIII

CrIII

O

OH

OH O

OH

OH

OH

OH

O OH

CrVI

CrVI

O

O

O O

O

CrIII

CrIII

O

OH

OH OH

OH

OH

OH

OH

OH OHH


Blue Passivates on Zinc

The requirements for blue passivates are diversified. From a simple conversion coating to a high performance coating with excellent corrosion protection and a decorative appearance, every-thing is specified. No matter what the requirement is, Atotech has the answer!

Passivate Features Minimum Corrosion Resistance White Rust (ISO 9227)

Unifix® Zn 3-17 Cobalt-free basic blue passivate up to 24 h

CorroTriBlue® Worldwide recognized blue passivate 24 h

CorroTriBlue® Extreme Passivate with improved corrosion protection and deep blue color 48 h

Unifix® Zn 3-13 Cobalt-free passivate for medium corrosion performance 48 h

Unifix® Zn 3-15 L High performance blue passivate, approved for Audi TL 194 72 h

Tridur® Zn B High performance blue passivate, approved for Ford S449 72 h

Yellow Passivate on Zinc

It is Atotech’s goal to lead the change to greener technologies and reduce the impact on people and environment. For this reason Atotech's Cr(III)-based yellow passivate does not contain sele-nium compounds which are known to be used to enhance the yellow color of the film adding no other benefit. Atotech offers a dye to intensify the color if required, which is even approved for use in the food industry.


Tridur® Zn Y3 Patent protected selenium-free yellow passivate 96 h

Unifix® Yellow Dye to intensify the yellow color of passivates, e.g. Tridur® Zn Y3, EcoTri® HC2

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Iridescent Passivates

The brand EcoTri® stands for exceptional corrosion protection and reliability. Widely recognized and approved for the auto-motive industry are products like EcoTri® and EcoTri® HC. Newer generations offer simplified wastewater treatment and economic operation at ambient temperature without com-promising the performance. By further combining the new generation thick film passivates with innovative nanotechno-logy new trends can be set.


EcoTri® Iridescent thick film passivate with global auto-motive approval for all zinc and zinc alloys

96 – 120 h

EcoTri® HC Iridescent thick film passivate withstanding heat treatment up to 210 °C for 8 h on zinc and zinc alloys

EcoTri® HC2 Iridescent thick film passivate for easy wastewater treatment, suitable for all zinc and zinc alloy surfaces

EcoTri® LT Iridescent thick film passivate operating at room temperature on all zinc surfaces

EcoTri® HC2 Nano New innovative passivate with nanotechnology for most stringent requirements when no additional sealer can be applied

120 h

Tricotect® – Regeneration Unit for Passivates – Emphasizing the Green Approach

With zinc and iron content increasing during the operation of the passivate the performance of the passivate is compromised towards the point for dump and remake. Consistent production performance and virtually unlimited lifetime can be achieved when operating the passivate with Atotech’s regeneration unit Tricotect®. The exchange resin Resin XL3 selectively removes zinc and iron from the solution.

▪ Easy to handle – Only a few minutes operator time, no mishandling▪ Safe to handle – Consistent regeneration condition and

process performance▪ Green to handle – No direct chemistry contact for operators safety and less waste

Besides the cost benefits which can be achieved when operating with Tricotect® also the environmental footprint can be reduced.


Clear and Blue Passivates on Zinc Nickel

In addition to thick film passivates, Atotech as leading supplier for zinc nickel electroplating has developed a diversified portfolio of passivates that are specially designed for zinc nickel.


EcoTri® SB True blue passivate, outperforms conventional thick film passivates 300 h

Tridur® ZnNi Clear Clear appearance, for stainless steel look with sealer 360 h with sealer applied

Rodip® ZNX Iridescent cobalt-free passivate, patent protected technology 240 h

Unifix® Fe/Ni 3-12 L Bluish iridescent passivate with glossy appearance 240 h

Unifix® Ni/Fe 3-10 L Passivate used over Zinni AC AF 210 on brake calipers with Sealer 300 W 120 h on brake calipers

Direct Passivates on Zinc Die Cast


Unifix® ZK 4-73 Produces a uniform grey appearance on zinc die cast

200 h

Unifix® ZK 5-75 High performance passivate on zamak

System for the Window Frame Industry

Passivate Features Corrosion Resistance White Rust (ISO 9227)

Tridur® Matt The specially developed matt system for zinc surfaces using nanotechnology produces an appealing aluminum look. With Corrosil® Matt all iridescence is covered without tenting holes and excessive last drop formation

1000 h

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Automotive Approvals

Surface Finishes for Zinc

OEM Passivate Sealer Performance

Coefficientof friction

ISO 9227

White rust Red rust

Audi TL 194 Unifix® Zn 3-15 L Sealer 300 WL7 0.9 – 0.14 192 h 600 h

Ford S449 Tridur® Zn B + Tridur® Enhancer Corrosil® 501L 0.14 ± 0.03

96 h 72 h (4 h 120 °C)

384 h260 h(4 h 120 °C)

GM GMW 3044 N EcoTri® HC2 Nano 120 h 240 h

GM GMW 3044 G

EcoTri® or EcoTri® HC

Corrosil® Plus 501 (BG)+ Rogard Lube 100

0.13 ± 0.03 120 h 240 h

Unifix® Zn 3-15 L Sealer 300 WL7

Hyundai-Kia MS 61-15 PFZn8

Tridur® Zn B 72 h24 h(1 h 150 °C)

240 h168 h(1 h 150 °C)

Toyota TSH6524G EcoTri® 72 h 312 h

VDA VDA 237-299.05 EcoTri® HC2 Sealer 300 W 120 h 432 h

VDA VDA 235-104.20Unifix® Zn 3-15 L Sealer 300 WL7

0.9 – 0.14 96 h 240 hEcoTri® Corrosil® Plus 501 (BG)

+ Corrosil® Plus 415

VDA VDA 233-101.Zn EcoTri® HC 96 h 240 h

Surface Finishes for Zinc Iron



ISO 9227

White rust Red rust

GM GMW 4700 Zn-Fe EcoTri® Corrosil® Plus 501 (BG) 480 h

VDA VDA 233-101.ZnFe EcoTri® Corrosil® Plus 501 (BG) 240 h 600 h


Surface Finishes for Zinc Nickel



ISO 9227

White rust Red rust

Ford WS-M21P44A2 EcoTri® Corrosil® Plus 501 (BG)

+ Rogard Lube 100 0.14 ± 0.03 360 h 960 h

GM GMW 4700 Zn-Ni Type A

Rodip® ZNX 480 h

EcoTri® 480 h

GM GMW 4700 Zn-Ni Type B EcoTri® Corrosil® Plus 501 (BG) 240 h 1000 h

GM GMW 4700 Zn-Ni Type B Code G EcoTri® Corrosil® Plus 501 (BG)

+ Rogard Lube 200 0.13 ± 0.03 240 h 1000 h

Hyundai-Kia MS 611-15 PFZnNi8

Tridur® ZnNi Clear Corrosil® Plus 501 (BG)200 h 1200 h

Unifix® Fe/Ni 3-12 L Sealer 390 W

PSA B15.4102 EcoTri® Corrosil® AL 2007 0.15 ± 0.03 200 h 720 h

Toyota TSH6530G EcoTri® SB 300 h 1000 h

VDA VDA 237-299.15 Unifix® Ni/Fe 3-10 L Sealer 300 WL7

0.9 – 0.14 120 h 720 hVDA VDA 235-104.25

Unifix® Ni/Fe 3-10 L Sealer 300 WL7

EcoTri® Corrosil® Plus 501 (BG)+ Corrosil® Plus 415

VDA VDA 233-101.ZnNi EcoTri® 168 h360 h

720 h720 h

Atotech Main OfficeErasmusstr. 20D-10553 Berlin

Phone +49 (0)30 349 85 0Fax +49 (0)30 349 85 777 www.atotech.com

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Atotech – We Supply Solutions

Atotech is one of the world’s largest suppliers of metallization production solutions for GMF (general metal finishing), PCB (printed circuit board) and semiconductor wafer applications. Atotech’s in-ternational experience and market know-how provides you with:

Widest Product RangeAtotech’s extensive knowledge and vast product offering gives you highly productive systems and single-source responsibility. Solid research and development combined with decades of field-proven processing is your assurance of the best electroplating systems in the world.

Highest Product QualityAtotech only works with certified suppliers to ensure the highest quality product with consistency second to none. Adherence to international quality standards is a way of life at Atotech.

Worldwide ServiceWith manufacturing, sales and service locations throughout the world, Atotech is positioned to effectively assist you now and in the future.

Reliable DeliveryAtotech’s worldwide production and warehousing help keeping you in production, day after day, year after year. You will save storage costs while protecting against lost production capacity.

Environmental Know-HowAtotech is committed to providing products and processes that are environmentally responsible according to the most stringent requirements on a global base.

Atotech regional Headquarters are situated in Rock Hill (USA), Berlin (Germany) and Yokohama (Japan)

conversion coatings 04.09

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