| 摘要 |
PURPOSE:To prevent the peeling of a coating layer, by forming a copper-oxide layer on the mold surface of a copper mold for casting, and by thermally spraying an oxide-type ceramic powder on the above layer so as to simultaneously form an intermediate layer of mixture and a coating on the above. CONSTITUTION:The surface of a cavity 4 of a copper mold 1 composed of a copper alloy containing about 1-4% Cr is pickled with nitric acid, etc., to apply acid corrosion to the surface by etching, which is heated to about 200-300 deg.C in steam to form a copper-oxide layer 5 of about 5-50mu thickness on the surface of the cavity 4. Subsequently, an oxide-type ceramic powder (SiO2, Al2O3, ZrO2, etc.) is thermally sprayed on the surface of the above copper- oxide layer 5 by using plasma jet, etc., so that an intermediate layer 6 (about 50-100mu thickness) consisting of copper oxide and oxide-type ceramic and a coating layer 7 (about 10-500mu thickness) consisting of oxide-type ceramic are simultaneously formed. In this way, the coating layer 7 practically free from peeling can be formed on the surface of the copper mold 1, and the protec tion of mold surface and the regulation of thermal conductivity can be effective ly carried out.
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