plating, anodizing, & finishing Q&As since 1989
Theoretical understanding of hard chrome plating
October 17, 2008
What is the current status of theoretical understanding of hard chrome plating based on Cr6 ?
The mechanisms of hydride production ? The cracking as a result ? The decomposition of hydrides ? The BCC Cr ?
How do the bath parameters achieve the desired results for conventional hard chrome plating ? Using various catalysts such as : Sulfuric, fluoride, complexed fluorides, etc. ?
What is the mechanism of thin dense chrome ? Such as the one touted by Armoloy ?
What is the cause of the nodules? What are the conditions, etc. Why thin dense chrome up to 7/10 mil or even 1mil = 1/1000 inch is not cracked ?
What is current status of understanding of catalytic anions such as sulphate, fluoride, etc.
Are there any trivalent baths comparable to the hard chrome 6?
Are there other metal plating baths of equal properties , hardness and lubricity from nodular surface etc. ?
electrochemist - Greece
October 23, 2008
A paper by N.V. Mandich presented at AESF 82
Technical conference, SurFin 95 (Baltimore, MD, June 1995) gives a comprehensive "Chemistry of Chromium"
The paper should be available from AESF, now called NASF
1155 Fifteen Street NW,
Washing DC 20005
Telephone 202-457-8404, FAX 202-530-0659 (www.nasf.org)
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [affil link to the book on: Amazon or AbeBooks ])
October 27, 2008
Just to add that there is at least one company that claims to have a proprietary process to plate tri chrome as hard as Cr6 and even harder. It is a brush plating company by the way. G. Marrufo-MexicoGuillermo Marrufo
Monterrey, NL, Mexico
October 28, 2008
Unless there is something very recent, Tri-chrome brush plating is limited to a very thin coating. OK for decorative, but not thick enough for "hard" chrome or "functional" chrome.James Watts
- Navarre, Florida