SILICON NITRIDE BASED CHARGE AND METHOD FOR PRODUCTION OF ARTICLES THEREOF Russian patent published in 2017 - IPC C04B35/593 B82Y40/00 

FIELD: chemisty.

SUBSTANCE: invention refers to the field of production of articles of silicon nitride based high-temperature construction materials which may be used in engine production, mechanical engineering and other high-technology industrial branches, in particular in manufacture of complex geometry parts requiring mechanical treatment, e.g., ceramic ball bearings. Silicon nitride based charge contains 10-15% wt% sintering additives and technological connective with sintering additives containing fraction of nanodispersive powders at the level 40-60%. Nanodispersive powders with specific surface of 30-50 m²/g are produced by methods of heterophase precipitation or co-precipitation. A method for production of articles using above silicon nitride based charge includes grinding of silicon nitride powders and sintering additive powders in planetary-type mill, introduction of technological connective (PVAL), pressing of blank and sintering under nitrogen pressure. The pressed blank is subject preliminarily to mechanical treatment using hard-alloy tools, then technological connective is removed in the air at temperatures of 500-1100°C, then sintering is carried out in vacuum with heating up to a temperature of 1600°C and after that in nitrogen medium under pressure of 3-4 MPa and temperature of 1800-1850°C. The final mechanical treatment is performed using suspensions based on super-hard abrasive materials.

EFFECT: production of ceramics with porosity max 0,1%, strength min 800 MPa and simplified technology for manufacture of complex geometry articles.

4 cl, 2 ex, 4 dwg