PROCESS FOR PREPARING PROTECTIVE COATING ON FRICTION CARBONACEOUS PRODUCTS Russian patent published in 1994 - IPC

FIELD: machine building. SUBSTANCE: the process for preparing a coating comprises preparing a colloidal silicophosphate solution by adding a silicic acid sol to a manganese dihydrophosphate solution in orthophosphoric acid neutralized with potassium hydroxide and an aqueous ammonia solution to pH of 3.0-4.5. The solution is then used to prepare a suspension using amorphous boron and boron nitride, the ratios of the components being as follows (wt % , calculated as the main substance); 18-30 amorphous boron; 1-5 boron nitride; 5-7 manganese dihydrophosphate; 3-7 potassium hydroxide; 40-55 orthophosphoric acid; 2-12 an aqueous ammonia solution; and silicic acid sol. The coated product is heat treated at 500- 580 C in a neutral atmosphere. EFFECT: improved properties of the protective coating. 2 tbl