METHOD OF APPLICATION OF PROTECTIVE COATS ON ARTICLES MADE FROM CARBON GRAPHITE MATERIALS (VERSIONS) Russian patent published in 2008 - IPC C04B35/52 C04B41/87 

FIELD: manufacture of carbon graphite articles with protective coats for electronic and chemical industries; manufacture of semiconductor materials.

SUBSTANCE: proposed coat is used for articles working in atmosphere of silicon or germanium vapor. Proposed method includes application of protective coat on articles made from carbon graphite materials; protective coat contains the following components, mass-%: silicon nitride ground to fractions of 200 mcm, 30-85; binder at viscosity of 10-300 stokes diluted to required consistency, 15-70. Binder contains mixture of 40-60-% solution including 70-75% of phenol formaldehyde resin, 18-22% of dichloropropanol and 5-10% of benzyl and/or isopropyl alcohol, 40-60% of powder containing 90-95% of finely dispersed graphite and 5-10% of para-toluene- sulfochloride and/or toluene sulfonic acid. Then, article is dried in drying cabinet first at temperature of 60-70 C for 20-30 minutes and then at temperature of 230-260 C for 40-60 minutes, after which article is cooled in atmosphere. According to second version, prior to application of protective coat, article is impregnated with aqueous solution of saccharose at content of sugar of 40-80% for 5-10 minutes. According to third version, article is subjected to preliminary impregnation in suspension containing 20-30% of solution by weight containing 70-75% of phenol formaldehyde resin, 18-22% of dichloropropanol and 5-10% of benzyl and/or isopropyl alcohol, 25-30% of finely dispersed graphite powder at addition of 5-10% of para-toluene-sulfochloride and/or toluene sulfonic acid and 40-50% of ethanol.

EFFECT: reduction of time required for conducting the process; reduced power requirements; enhanced protection of articles working in atmosphere of silicon or germanium vapor in manufacture of semiconductor materials.

4 cl, 3 ex