The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Vapor deposition color anodizing for our lighting fixture line

I am looking for an anodizing process for aluminum that can produce uniform colors. I have heard that vapor deposition is more precise than the tanks which are very hard to control. Do I want a Microplasmic process, CVD, PVD, IVD, PEPVD, sputtering or thermal spraying?

Susan Hakkarainen
Lighting fixtures - Willow Grove, Pennsylvania, USA
2004

---

None of the processes you list are anodizing processes. Most deposit a coating on the surface. For typical PVD processes, including sputtering and cathodic arc, the color is very uniform and very reproducible, so much so that the processes are used extensively to coat door knobs, faucets, et al. Having said all than, it is not a good idea to try to use these processes to coat aluminum. First of all, these coatings are very hard, and aluminum is very soft, a combination that leads to cracking and coating delamination. Second, the deposition temperatures are pretty high -- above the temperature at which most aluminum alloys anneal, so the aluminum loses strength and hardness. You might be able to get away with a flash of these on top of nickel-plated aluminum.

Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
2004