PURPOSE: To improve wear resistance over a wide frequency range and to prolong the life of a device using these sliding parts by forming a nitriding treated layer on the surface of a base material and providing a solid lubricant layer of a specific thickness thereon.

CONSTITUTION: The nitriding treated layer essentially consisting of iron nitride is formed by an ion nitriding method on the surface of the metallic base material consisting of an iron system. The solid lubricant layer, such as chemical conversion film of manganese phosphate having 0.5 to 20μm thickness is provided on the surface of this nitrided layer. Since the chemically inert iron nitride layer is formed on the solid lubricant layer, the temp. rise of the sliding surface is small and the shearing force of the solid lubricant is small, by which the coefft. of dynamic friction is additionally lowered. The good wear resistance is imparted to the frequency variable type refrigerant compressor even during low-and high-speed operation, if such sliding parts are used for this compressor.