| 摘要 |
PURPOSE:To improve the corrosion resistance and frictional characteristics of a Co coated Al or Al alloy member by melting part of the Al or Al alloy by heating to form an Al-Co alloy layer. CONSTITUTION:The surface of an Al or Al alloy member such as a plastically worked or cast member is plated with Co and part of the Al or Al alloy is melted by rapid heating from the outside to bring Al and Co into a violent exothermic reaction. The temp. is raised to about 2,000 deg.C by the reaction and NO2Al3, Co4Al13, Co2Al3 and CoAl compds. are formed. Since the compds. are dense and hard, diffuse and adhere firmly to the base, superior corrosion resistance and frictional characteristics are provided. When superior frictional characteristics are especially required, only Co plating is carried out. When superior corrosion resistance is especially required, Cr plating is further carried out after Co plating.
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