MIRROR AND METHOD TO FORM ITS PROTECTIVE COATING Russian patent published in 1994 - IPC

FIELD: optics. SUBSTANCE: mirror has a substrate, reflecting metal layer, and protective coating made of silicon carbide and nitride with the composition as follows: silicon carbide within 2 to 27 per cent by weight, the balance being silicon nitride. Method to form mirror protective coating comprises applying protective layer in a vacuum chamber by spraying original material onto cleaned reflecting metal layer produced on the substrate with original material formed as a target of silicon carbide with free silicon. Prior to protective layer applying the target is initiated in vacuum chamber in argon atmosphere, and protective layer is applied in nitrogen atmosphere at its 0.10 to 0.15 Pa partial pressure in vacuum chamber. EFFECT: durable protective layer. 6 cl, 2 dwg, 1 tbl