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Anti-reflective process for 416 stainless

1999

I have an optical assembly made of 416 stainless steel that is giving me reflecivity problems. I'm looking for a means of giving it a low-reflectance surface. Paint is not a good option, because lenses must be epozied to the surface and masking these areas of the surface is extremely difficult. Also, cleaning of the lens with acetone [on eBay or Amazon] is likely to mess up the paint and possibly smear it onto the lens.

I prefer a chemical process which alters the color/ reflectivity of the metal's surface, will allow epoxy adhesion similar to that of the untreated surface, and will cause minimal out-gassing in a vacuum environment.

That's a tall order, but does anybody have any suggestions. . . please?

Andy Chouinard
Conway, Arkansas

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I'd look at a thin PVD coating, maybe 0.2-0.3 microns thick. If it's a Zone 1 coating it will have an open columnar structure, making it a poor optical reflector. As the coating is applied in a vacuum, it is certainly vacuum compatible -- more so than any chemical coating. Most job shop houses won't do the job, but you should be able to find a bell jar e-beam or sputter system at a university or on the used equipment market. Colorado School of Mines in Golden, CO, has a couple of units that could be used, as well as students to do the work, assuming that the assembly is not too large.

Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
1999

I feel that a black coating would do a good enough job. The possibilities are black oxide type coating or passivation, or back chrome plating.

Mandar Sunthankar
- Fort Collins, Colorado
1999