plating, anodizing, & finishing Q&As since 1989
Trivalent Chrome Rusting
We are having a problem with Trivalent Chrome plated parts on steel. The parts seem to rust over a short period of time around the rack mark and the area where the chrome meets the nickel. It seems that any water or condensation left on the part will rust in this area within a few days. These areas seem to be extremely active even after a proprietary post dip is used. Does anyone have a solution without using hexavalent chrome?Jeff Sparano
Metal Finishing - Cleveland, Ohio
Firstly, ask the supplier of your chemistry if others have experienced this problem and what are the causes and possible ways to rectify the problem.
Secondly, I would suggest adding a rinse aid/rust retardant to the final hot water rinse. This has been successful for some of the companies I do business with who have been using tri chrome for 20 years.Gene Packman
process supplier - Great Neck, New York
I am told that our company was one of the first in the U.S.A. to have a tri-chrome bath put into our facility, if that is true or not I'm not positive but that is what they tell me? Anyway.......after we Ni plate our product then rinse and Cr plate it(US26) & (US26D) we run it into a hot water rinse that is 180 degrees, maybe that will help or as gene has said try adding some kind of a rinse aid to the water rinse,these have proven very well for alot of people, I know Pavco & Macdermid make great products for rinse waters!Brian Gaylets
McKinney Products(Assa abloy) - Scranton, Pennsylvania, U.S.A.
Use a hot rinse, very important with trivalents.
Your solution supplier should have something to help iron reduction and removal.
Dummying always helps.Steve Clark
English Custom Polishing - Belfast, Maine, U.S.A.
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