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Is Chrome plate Burning or Whitewashing?
Q. I'm having trouble with the chrome tank. There is whitewashing and burning in the HCD areas and A surfaces of chrome plated parts.
I checked the levels of chrome, ratio, and sulphate levels: they are 31 oz chrome, 0.16 sulphate level, and the ratio is 194.
Now my problem is that we have tried everything: adding sulfuric acid to raise the sulphate level, barium carbonate to lower the sulphate level, chromic acid to raise the chrome levels which are very inconsistent from day to day, and dummy plating. there is a lot of solid at the bottom of the tank also.
Would you please advise me as to what I can do to rectify the problem. I haven't ruled out contamination of chlorides and fluorides. Would you tell me an easy method for testing for chlorides fluorides.
I am desperate for help. Thanks,
Carolyn Leonard- Las Vegas, Nevada, United States
2003
"Chromium Plating"
by Weiner & Walmsley
on
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A. Have you checked your temp. and current. You may have a bad thermocouple if you don't have an actual thermometer for reading in the tank.
Also check to make sure your power supply is actually putting out what it says it is. Check the contact of the part to the rack or holder.
Tom H.
Tom Haltmeyer- Peoria Arizona USA
2003
A. Burning is too high current density for the chemistry balance. White Washing is usually either passive nickel going into the chrome tank, or current interruption caused by breaking contact or a rectifier malfunction.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
2003
A. Check your Bright Drag-out and rinse tanks-they may be contaminated. Try rinsing in chrome drag-out before putting in chrome tank and also check the addition of DC 1.
Mumtaz Ali- Surrey, B.C., Canada
2003
2003
A. Carolyn Leonard,
Chrome burning and white wash problem from the chrome tank.
Do you have nickel activator and chrome predip prior to the chrome tank?
Check the part for burning ,a part look like white wash put your finger and gently rub on white wash or burning if the surface look like rough (not smooth) then this defect is the chrome burning. If smooth surface this is white wash defect.
white wash :
Check falling part in your dur nickel tank during the production, If any falling part in your dur nickel tank pull out the part.
check falling part in chrome tank ,pull out the part
check sulphate in chrome tank. check the ph of rinses prior to the chrome tanks.
Burning:
check the ratio in chrome tank.
Check the ram( rectifier )
check the chrome temp. c
heck the ripple for chrome rectifier
check the steady current during the chrome plating.
Popatbhai B. Patel
electroplating consultant - Roseville, Michigan
A. As an answer for anion analysis (F, Cl), try ISE.
James Totter, CEF
- Tallahassee, Florida
2003
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Ed. note: If after reading this thread, you feel that you have "whitewash", additional info is available:
Thread 1963 "Whitewash on Chrome Plate"
Thread 21467 "Whitewash on Bright Nickel/Chrome Plated Parts"
Chrome burns when 4 parts on rack but not with 2 parts
"Electrodeposition of Chromium from Chromic acid Solutions"
by George Dubpernell"
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Q. Sir, I am facing burning in bright chrome bath following bright nickel, in High current area.
Actually problem is that when I load 2 fenders per jig there is no issue of burning nor chrome miss, but when I load 4 fenders per jig, the face is burning on backward facing two pcs but front 2 pcs are ok.
I wonder what's wrong with that?
Temperature 35-40 °C
Density 20-22
sulphate ratio 1.3
Amp/dm2 8
Problem repeats only when I load 4 pcs/jig on back ward pcs, but front pcs ok.
When I hang only 2 pcs there is no problem also. My plant jig actual capacity is 4 pcs/jig.
Please guide what could probable cause.
Waqas
(photos added August 18)
Employee - Pakistan,Karachi
A. Khalid,
chrome burning issue - check chrome concentration and ratio
parts or anode drop in tank & touching to the parts. Check temp in chrome, passive nickel, CHECK AMPS, MAKE SURE YOU HAVE CHROME PRE DIP BEFORE YOU PLATE CHROME.
Popatbhai B. Patel
electroplating consultant - Roseville, Michigan
August 17, 2018
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