| 摘要 |
PURPOSE:To improve the penetration of a 1st coating layer into a sand core and to securely bond the 2nd coating layer by specifying the coating materials of the 1st and 2nd coating layers to be formed on the surface of the sand core. CONSTITUTION:The sand core is immersed in a mixture composed of powdery refractories and an alcohol soln. of a phenolic resin to coat the mixture on the surface of the sand core. After this coating layer is dried, the coating layer is heated to cure the phenolic resin. A mixture composed of flaky stainless steel foil and an org. solvent dilute liquid of a heat resistant silicone resin is coated on the surface of the 1st coating layer by dipping, brushing, spraying, etc., at the time of forming the 2nd coating layer on said surface. The coating layer is dried to securely bond and fix the flaky stainless steel foil, by which the penetration of a molten metal at the time of high-pressure casting is prevented.
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