| 摘要 |
PROBLEM TO BE SOLVED: To obtain an Si3 N4 material suitable for bearings or valves of internal combustion engines or the like, which require abrasion and thermal resistance. SOLUTION: This sintered Si3 N4 ceramic material comprises at least 80 wt.% of Si3 N4 crystalline particles and 0.25-1 wt.% of particulate additives which are selected from the group consisting of TiC, WC and TaC, and have a detectable maximum grain size of <=4 μm, preferably <=3 μm, when the grain size is measured on a microscope image of a fine texture having the area of 75 mm<2> of a polished Si3 N4 material. Use of the Si3 N4 sintered material containing the additives having a small detectable maximum grain size can cause such preferable results that the rotational contact fatigue life is improved, the abrasion rate is decreased and the bending strength is increased. |
