Summary for armoloy tdc Discussion
tarnish-resistant nickel plating substitute? Armoloy TDC comes up in a short exchange where Jeffrey Holmes, CEF, explains that “TDC” means Thin Dense Chrome and that Armoloy® is the correct proprietary name for a chrome electroplating process. He suggests that this should help the original poster research the coating further. In a later reply to Stephen, he notes that electroless nickel gives consistent thickness and can solve gauging problems, but it is more expensive than electrolytic nickel. He also cautions against assuming cadmium is the only option: cadmium, zinc, and aluminum are the plating types that provide galvanic corrosion protection, while most other platings act as barrier layers and can actually worsen corrosion if porous or scratched. He adds that aluminum plating is expensive and urges readers to challenge assumptions when choosing a substitute.
Q. I need to know something about “Armalloy tdc” process.
PIERO D [surname deleted for privacy by Editor]
EN plating shop – MILAN, ITALY
2004
A. Hi, Piero. I can tell you that “TDC” is an acronym for “Thin Dense Chrome”, and that the correct spelling of the brand is Armoloy®. It’s a proprietary name/type for chrome electroplating. Hopefully this is enough that you’ll be able to further research it. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
Q. For years our engineering department has chosen nickel-plating as the corrosion resistance method for all carbon steel products we manufacture. The two biggest problems we have experienced are 1.) threads cut under/over size to allow for plating have not been gauging and 2.) a tarnish or corrosion has been reported to have developed (especially in some foreign locations) on the nickel.
We have been looking for a suitable substitute to nickel-plating since we no longer can use cadmium or zinc plating. Armoloy is what we have been experimenting with on some parts. Any ideas?
Stephen Donaldson
Aerospace Industry – Houston, Texas
2005
A. Armoloy (which is simply fairly thin hard chrome plating) may work well. It should not tarnish as nickel does. Corrosion resistance could be a problem. It depends on the environment. Electroless nickel might be a good choice too.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
2005
A. Hi Stephen. Electroless nickel plating is consistent in thickness and would solve the gauging problem, but it is much more expensive than electrolytic nickel plating.
It is understandable that you can no longer do cadmium plating because it is a bio-accumulative poison which everyone is trying to remove from the environment, but you haven’t said why you can’t do zinc or zinc alloy plating — and it is important to challenge assumptions to get the best answers. Remember that only cadmium, zinc, and aluminum plating offer galvanic corrosion protection, and aluminum plating is very expensive. Other platings are more noble than steel and are “barrier layer” rather than “sacrificial”; if they are porous due to thinness, or become scratched, they accelerate corrosion and can be worse than no plating at all :-)
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.