Refrigerant compressor, cooler and refrigerator

Has a compression element having a sliding part of the metal material, at least one sliding surface of the sliding element, to form a mixed layer in which is dissolved molybdenum disulfide, further molybdenum disulfide to the surface of the mixed layer of a single layer is formed, resulting the initial break the single layer, while reducing the sliding loss, even single layer is peeled off, the solid by molybdenum disulfide of the mixed layer is cleaved at a low friction coefficient exert lubricating action, the friction coefficient of the sliding portion is lowered, the sliding loss is reduced.