US Patent 7651727 Method for surface treatment of sliding portion

There is provided a method for surface treatment of a sliding portion of a product, which is an economical method, has less risk of polluting the working environment, or causing a fire by the powder dust, and yet enables high lubricativeness to be achieved, and many concavities to be formed on the sliding portion while simultaneously providing lubricativeness. Injection particles, obtained by blending soft-metal solid lubricant particles the surfaces of which have been oxidized and layered-structure solid lubricant particles, are injected onto a surface of the sliding portion of the product to be treated at an injection speed of 150 m/sec or more, thereby to diffuse and penetrate the surface to form a layer of the injection particles, and to form many concavities on the surface of the sliding portion.