Where theworld gathers for metal finishing
Q&As since 1989
-----
Black chrome adhesion problem
Q. We have been experiencing many problems with black chrome plating, the black finish is very nice but after while it turns to dust and falls off the articles plated. It don't matter what the base metal is being plated, or how its been cleaned . Also, the finish will turn from a black color to a gray if plated just seconds to long. Any help would be deeply appreciated on this subject.
James Warrenplating - Detroit, Michigan
2004
"Chromium Plating"
by Weiner & Walmsley
on
AbeBooks
** rarely available **
or
Amazon
** rarely available **
(affil links)
"How to Restore
Metal Auto Trim"
by Jeff Lilly
on
AbeBooks
or
eBay
or
Amazon
(affil links)
A. James,
Typically for black chrome is the low efficiency for the solution, it could happen that you produce to lots of hydrogen in to the material this also can be a phenomenon when you say at the deposit is gray. A gray finish can happens if the parts have be burn with to high current density. Also some contamination of chloride will show some gray deposit and small dots. How long is your time in the solution it should be like 4-7 minutes and with a current between 10-70 A/dm2, temperature between 13-24 °C. Please let us get some more information type a photograph from the parts.
Regards,
Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden
2005
Q. Thank you for your reply about the black chrome problem . The grey deposit is in the low current density area, so I do not believe it is a burn (remember it goes from a nice black to grey the longer the parts are in the bath.) and when finished the high current area is a nice black finish but when a little heat is applied to this area the black turns to dust. My process time is 4 -5 minutes at 65 °F at 200 A/ft2 .
I've had high chloride problems before but never problems like this, I use silver oxide to remove the chloride but this is no longer affordable. In short we use to be able to leave the parts in the black chrome tank up to 20 minutes if we wanted, now we can't go any longer then 5 minutes without the grey or turning to dust problem occurring! more help on this would be deeply appreciated, thank you.
James Warren [returning]- Detroit, Michigan
2005
A. James,
Can you take a little solution from your solution and heated up and after that cooling the solution and try to make a plating test on it. It could be at you have problem with to much hexavalent chrome who have be bonded and you not can reduce to trivalent chrome.
Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden
2005
Q. I'm current doing a black chrome project. The work condition is similar is above; however the workpiece has uneven-plated problem.
Is there anything I overlooked?
- Malaysia
October 29, 2010
A. Hi, John. If 99 things are right and one is wrong, you will still get poor plating. It is very difficult for anyone to guess what things you checked and which things you overlooked. Furthermore, "uneven-plated" doesn't give us many clues. Is the plating rough (shelf roughness, burning, lack of filtration?). Is there incomplete coverage in the LCD area? Is there pitting? If you strip the black chrome away, bringing it back to a nickel plated surface, is everything fine?
There are proprietary black chrome plating baths available which will come with technical data sheets instructing you how to operate them, and which offer a technical service laboratory which will help you analyze what is wrong.
If you can only use your own formulation, we need to at least know what temperature, concentration, additive, and current density you are trying to operate at, and specifically what defects you encounter. Do you do any hull cell plating? If so, what does it indicate? Do you have photos available?
Good luck and regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 31, 2010
Q. I also have problem in black chrome plating, my end product is burning. I have adjust the current and temperature is between 18 - 23 °C. My chrome is in optimum. Hope anyone can help. Thanks in advance.
Erani Hadi- Johor, Malaysia
May 20, 2011
Q. We are plating with black chrome and when it comes time to wipe them down before being shipped out the plating is coming off the parts and turning more of a grey color.
yvonne newsome- united states
October 11, 2017
A. Hi Yuvonne,
I'm not a supporter of Black chrome at all.
This is an inherent problem with Black Chrome.
Perhaps you'll have more luck with special paints used only on plastics.
regards,
Khozem Vahaanwala
Saify Ind
Bengaluru, India
December 14, 2017
Q, A, or Comment on THIS thread -or- Start a NEW Thread