PREPARATION OF FLAME SPRAY FILM FOR TRANSFER

PURPOSE:To drastically increase the number of time capable of repeatedly using a core material, in a method for forming a transfer flame spraying film on the surface of the core material having coefficient of expansion higher than that of said transfer flame spraying film, by prelimiarily forming an anodic oxidation film on the surface of the core material. CONSTITUTION:For example, in preparing the cylinder of a compressor for an engine, an anodic oxidation film 1' is applied to the plasma spraying surface of a core material 1 made of an Al base alloy. In the next step, a desired flame spraying material is uniformly flame sprayed to the core material 1a in a desired thickness. At this time, blast treatment applied as the pretreatment of usual flame spraying is not applied to the core material 1a and only degreasing is applied thereto while the core material 1a is preheated prior to flame sparying to sufficiently expand the same under heating. When the core material is cooled to a room temp. after flame spraying, a gap is formed between the flame spraying film 10 and the core material 1a because of the difference in coefficient of expansion therebetween and, because the core material 1a is smooth, the film 100 can be easily separated. The mantle 12 of an Al die cast mold 11 is covered with this film 100 and the outer periphery of said film is subjected to internal chill transfer by an Al base alloy 13.