Letter 3309

Black Optical Coatings on 316L Stainless Steel 

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I have an application where we need to decrease the parasitic optical reflections on a 316L stainless steel part. The used light is around 890 nm wavelength.

What kind of black optical coatings are available?

Do you have any ideas on where I can look for this information?

Thank you for your help.

Pere Llosas
- Switzerland

I have seen black chromated alkaline zinc used over brass laser timing gears for an optical timing device which had similar optical requirements. In this case prior to black zinc, a woods nickel would be required in order to zinc plate the stainless. The black chromate had to be baby sat during the chromating operation due to the high QA requirements.

Ward Barcafer, CEF
aerospace - Wichita, Kansas

Try a room temp black oxide coating. Although this is not a true black oxide, it should provide a reasonably dulled almost matte finish.

Dan Brewer
chemical process supplier - Gurnee, Illinois