Black Zinc Plating

When we talk about "Black Zinc Plating", we are actually referring to Normal Zinc Plating… followed by Black Chromating or Black Passivation.

So… What do you need to know???

First of all, you need to understand the following…

1) There is no such thing as “Black Zinc Plating”…

2) There is Zinc Plating followed by Black Chromate or Black Passivate.

Black Chromates...

Black Chromates were (and still are) a very common Chromate Conversion Process Solution that can be used to Protect and Color Zinc Plating Deposits / Coatings.

 

Most (if not all) OEMs such as Volkswagon, GM, etc… do not allow their Parts / Components to be processed through Black Chromate. Most Governments and OEMs recognize that the Protective Layer created by Black Chromating… is "Cr (VI) / Hexavalent Chromium Containing" and therefore Carcinogenic. So... Governments and OEMs looked for alternatives to Black Chromating.

Chromates are banned within the European Union.

Black Passivates...

Therefore, a few companies researched and developed Black Passivates (that were "Cr (VI) Free"), which create a Black Layer that is not Carcinogenic (or at least definitely much, much less Carcinogenic). This development... is... without a doubt an Environmentally Friendly Improvement!

Probably one of the best Black Passivates available on the Market is ENTHONE’s PERMA PASS 7030.

Differences Between Black Chromates and Black Passivates…

There are a lot of differences between these two technologies…

1) Black Chromates give Corrosion Protection to your Parts / Components (and to the Zinc Deposit / Coating). The Black Chromate Layer protects the Zinc Coating against the Formation of White Rust. Black Chromates also have some limited “Self-Healing” Properties which are useful in protecting your Parts against future "stratches" etc…

2) The Black Passivates available on the Market DO NOT currently give any Corrosion Protection to your Parts!!! (Actually the above statement is not completely true as it seems that ENTHONE's Perma Pass 7030 is giving relatively significant amounts of Corrosion Protection - 72 to 240 Hours to First Formation of White Rust in Neutral Salt Spray Testing). Therefore... (outside of Perma Pass 7030) Black Passivates are simply a "Color" Finish. To get similar Corrosion Protection as the Black Chromates… your Parts will need to be processed through a Sealant. Also, a Sealant can be useful in “deepening” the Black Color and removing Iridescence from the Black Finish.

 

DIN 50979 - Electroplated Zinc and Zinc Alloy Coatings on Steel or Iron with Supplementary Cr (VI) Free Treatment

Just as an Important Point... DIN 50979 states that... For Zinc “Coatings” with Black Passivate and Sealant (Zn//Fn//T2) there are currently no generally accepted values for NSS Testing Corrosion Resistance.

Okay... in Summary...

Black Chromate is dead! And Black Passivation is NOT a great choice for High Corrosion Protection Demands. Possibly, the current Black Passivation Technology has its place for “Indoor” Applications where a “Nice” Deep Black Color is desired (example… indoor furniture applications etc…).


Exit Black Zinc Plating and Return to Zinc Plating...

Page copy protected against web site content infringement by Copyscape
black zink plating

Above... a picture of a Part plated in Alkaline Zinc, followed by a Black Trivalent Passivate, and then followed by a Specific Sealant.



Pictured below... Parts processed in Acid Zinc, followed by a Black Chromate... with NO Applied Sealant...

black chromate

Questions???

Can't find what you are looking for??? Click here to submit your Questions...

Looking for a High Quality Plating Company that can perform "Black Zinc Plating"... locally... globally... Contact Us...