plating, anodizing, & finishing Q&As since 1989
Testing adherence of chrome plated shafts
January 22, 2010
Q. We need to check the adherence, i.e., the bonding of hard chrome plated shafts.
What are the best and reliable tests?
What are the international standards for this test?
I have been in the industry over 40 years and we usually test with a strong tape or we make coupons and heat them up and then water quench.
We cannot perform this test on a finished; the customer wants it done on a coupon.
general manager - B. Aires, Argentina
January , 2010
A. Hi, Fred. I could be wrong on this, but I think if your customer wants coupons tested rather than the actual items, they should specify everything about the testing they want done, since it is they who are assuming the coupon test is representative, and I would not be so sure :-)
Hard chrome plating is a metallic bond far stronger than paint bonding, and I question whether any adhesive test even approaches being able to determine the bond strength of chrome plating. The "real" test would be the Modified Ollard Test where the plated article is put into a metallurgical "pull tester" until fracture (see letter 18002 for details), but this test (which can be may be done on real parts or coupons) may be rather impractical for your situation. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
January 30, 2010
A. Are those shafts ground? If so, there is no better way to test the adhesion of chrome. If it holds there it should be good for any other normal situation.Guillermo Marrufo
Monterrey, NL, Mexico