Silicon nitride based sintered body

摘要

Discloses a silicon nitride based sintered body composed only of uniform, fine crystal grains, and improved in both strength and fracture toughness in the middle and low temperature ranges. A crystalline silicon nitride powder composed of crystal grains whose longer-axis diameter is not more than 200 nm or an amorphous silicon nitride powder is used as material powder. The silicon nitride powder is sintered at a temperature of 1200 DEG C. to 1400 DEG C. or sintered with a product of sintering temperature ( DEG C.) and sintering time (sec) below 600000 ( DEG C.xsec) at a temperature of 1400 DEG C. to 1900 DEG C. Thus, a silicon nitride based sintered body in which the longer-axis diameter of silicon nitride and/or sialon crystals is not more than 200 nm is obtained.