| 摘要 |
A multi-layer solid lubricant coating film comprising an under-layer coating film (21) and an upper-layer coating film (22) formed on the upper surface of the under-layer coating film (21) is formed on the outer peripheral surfaces of both skirt parts (8, 9) of a base (1a) of an aluminum alloy-made piston (1). Each of the under-layer coating film and the upper-layer coating film contains at least one component selected from a polyamideimide resin, a polyimide resin and an epoxy resin which serve as binder resins, and the under-layer coating film also contains a graphite-containing or the like as a solid lubricant agent. The under-layer coating film is applied onto the outer surface of each of the skirt parts and then dried by the irradiation with a laser beam for about 10 seconds at a temperature-rising rate of 11.3 to 23.9˚C/sec using a laser heating apparatus. The upper-layer coating film is then applied onto the upper surface of the under-layer coating film, and the resultant product is subjected to a burning treatment. Thus, it becomes possible to provide a coating film formation method which enables the formation of a multi-layer solid lubricant coating film, in which the entire treatment time in the coating film formation process can be shortened as possible. |
