“…Silicon nitride (Si 3 N 4 ) ceramics have excellent properties such as high strength, high hardness, wear resistance, heat resistance, electrical insulation and selflubrication, which is an ideal material for rolling elements used in bearings [1,2]. The bearings with Si 3 N 4 ceramic balls or rollers are particularly suitable for working under high-speed, cryogenic or hightemperature, low-torque, and oil-lean lubrication conditions, such as spindle bearings in precision machine tools, windmill generator bearings and aerospace bearings [3,4]. Si 3 N 4 is a compound with strong covalent bond and low self-diffusion coefficient.…”