Patent ID: 7651727

Claim:
A method for surface treatment of a sliding portion, comprising the steps of: injecting injection particles, obtained by blending metal solid lubricant particles having oxidized surfaces to increase their surface hardness and layered-structure solid lubricant particles, at an injection speed of 150 m/sec or more onto a surface of a sliding portion of a product to be treated, said injecting step forming concavities on the surface of the sliding portion, the concavities having an average diameter of 0.1 to 10 μm and an average depth of 0.1 to 5 μm and substantially arched in cross section, on the surface of the sliding portion, said oxidized surfaces being obtained by a water atomization method; and diffusing and penetrating the surface of the sliding portion with the injection particles to form a layer of the injection particles on the surface of the sliding portion.