| 摘要 |
PROBLEM TO BE SOLVED: To produce an Alumite (R) member excellent in resistance to the generation of cracks in Amumit(R) coating caused by heating and to provide a method for producing it. SOLUTION: This Alumite(R) member is the one in which an Alumite(R) bath having a compsn. contg. 4 to 7% Zn, 1.5 to 3.5% Mg and 0.8 to 3% Cu, furthermore contg. one or more kinds among 0.05 to 0.6% Mn, 0.05 to 0.6% Cr, 0.05 to.6% Ni, 0.05 to 0.6% Co, 0.05 to 0.6% Zr and 0.05 to 0.6% V by <=1.2% in total, and the balance Al with inevitable impurities, and contg. 10 to 20% free sulfuric acid is used to form Alumite(R) sulfite under the conditions of 0 to 19 deg.C treating temp. and 1.2 to 3.6 A/dm<2> current density, which is subjected to hot water sealing at >=85 deg.C to form Alumite(R) coating having 5 to 24μm coating thickness on the surface, and the thickness (t) [μm] of the Alumite(R) coating and the cross-sectional hardness H [HMV] of the coating satisfy the condition of 450>H>2.3t+255.
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