| 摘要 |
PROBLEM TO BE SOLVED: To secure the static joining strength of a coating film and to improve its peeling resistance under themal impact, on the surface of an aluminum base material, by forming an oxidized coating film thicker than a naturally oxidized coating film in the process of or after roughening treatment therefor, subsequently thermal-spraying carbon steel or the like thereon and forming the coating film. SOLUTION: On the surface of an aluminum base material, a sprayed coating film of carbon steel or the like is formed by an atmospheric plasma spraying method or the like to improve its heat resistance, wear resistance or the like. At this time, the surface of the material is subjected to roughening treatment by shot blasting, high pressure water spraying or the like, moreover, in the process of or after this roughening treatment, the oxidized coating film of a thickness in a range by which the formation of the sprayed coating film is not disturbed is formed, and, after that, the thermal spraying is executed. Preferably, this oxidized coating film has a thickness of 10 to 500 nm and is formed by sputtering, anodic oxidation, high pressure water spraying under >=10 MPa, high temp. water spraying at >=50 deg.C or the like. In this way, the joining strength in the boundary between the sprayed coating film and the base material is improved, and, furthermore, thermal stress is relaxed to improve its peeling resistance under repeated themal impact.
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