PURPOSE: To improve the corrosion resistance of a casting by executing a casting by forming in order Ni and Al coatings on the mold face coming into contact with a molten metal and forming a Ni-Al coating layer on the surface of a casting.
CONSTITUTION: The coating of a Ni layer is executed on the surface of the mold including a core with a plating method, etc. and an Al layer coating is executed on its upper face via a chemical evaporation or plasma thermal spray, etc. In this case, the Al of the upper layer is diffused in the Ni layer with a diffusion treatment, if necessary, to form the Ni-Al alloy layer removing Ni2Al3. When casting is executed by filling a molten metal in this mold, the Al is diffused on the surface of a casting and the layer of an intermetal compound including Al is formed. With this intermetal compound formation, the corrosion resistance of a casting is improved.
KASHIMURA TETSUO
FUKUI HIROSHI
YOSHIDA TAKEHIKO
