PARTIAL SURFACE TREATMENT OF ALUMINUM DIE CAST PRODUCT

PURPOSE:To improve quality and to reduce costs by sticking halide of the metal to be coated on a part of the surfaces of die cast products of Al (alloy) then irradiating near IR rays thereto to heat only the surface layer part above prescribed temps. and accomplishing covering, diffusion and penetration in short time. CONSTITUTION:After copper chloride is coated on a part of one surface 5 of an aluminum die cast product 4, the coated surface 5 is placed in such a way as to face the irradiation surface area of the IR lamps 2 of a near IR heater 1 away by a prescribed distance therefrom. Electric power source switches for a blower 3 and the lamps 2 are turned on to irradiate near IR rays to the surface 5 for, for example, 90-120sec. The surface 5 is heated by this to 400-500 deg.C necessary for the reaction of the copper chloride and the diffusion penetration of the copper in the product 4, whereby the reaction is completed. Here, the parts of the product 4 other than the surface layer area of the surface 5 are not heated up to the reaction temps., and this heating does not lead to the generation of the blisters of the base material owing to the internal defects of the product 4.