Patent ID: 9719942
Date: 2017-08-01
CPC Classifications: C04B,F16C,G01N,Y10T

Claim:
1. A sintered ceramic which has excellent wear resistance and which is obtained by molding and sintering a molding powder with a specific surface area of 10 to 15 m 2 /g, the powder comprising silicon nitride and a sintering agent made of Al 2 O 3 and Y 2 O 3 , each of which is added at 3 to 6 wt %, wherein a bulk density is 3.1 g/cm an average grain size is 3 μm or less, and there are no flaw of 10 μm or more from a surface to a depth of 250 μm and no white spot (snow flake) of 20 μm or more when mirror-polishing a silicon nitride sintered compact and allowing transmission of halogen light having the wavelength between 500 nm and 800 nm therein.