BURDEN FOR PRODUCING CERAMIC MATERIAL Russian patent published in 1998 - IPC

FIELD: powder metallurgy, in particular, manufacture of ceramic constructional parts, including large-sized parts. SUBSTANCE: burden contains, % by weight: boron nitride 10-60; ultrafinely dispersed plasmochemical composition based on silicium nitride 40-90. Composition contains, % by weight: magnesium oxide 2-5; silicium nitride 95-98. Ultrafinely dispersed silicium nitride-magnesium oxide composition provides formation of dense fine-grained matrix structure from mutually mixed grains β-Si₃N₄ of hexagonal shape and less viscous, high-melting point interfacial phase in the form of magnesium silicates. Such microstructure provides predetermined strength and hardness to the material. Magnesium oxide is introduced into burden to provide dense structure in the process of hot pressing at more amiable conditions (temperature T= 1,550-1,600 C and specific pressure P(sp)=10-15 MPa) as compared to silicium nitride-yttrium oxide composition caking mode. Ceramic material produced on the base of such burden allows large-sized parts such as parts having diameter of up to 160 mm to be manufactured. EFFECT: improved quality of ceramic materials, reduced production cost by decreased power consumption and cost of raw material and wider range of parts produced from such materials. 1 tbl