COATINGS FOR COLUMBIUM AND COLUMBIUM BASE ALLOYS

摘要

A method of protectively coating columbium and columbium-base substrates for service at temperatures above 2000 DEG F comprising spray coating the substrate with a slurry consisting of a powdered mixture of silicon, aluminum and silver in a lacquer followed by diffusion treating the coated substrate in an inert atmosphere at a temperature in the range of 1900 DEG F to 2300 DEG F to form a layer of silicide intermetallic compounds adjacent the substrate and a layer of silver-silicon-aluminum alloy overlaying the first layer.