| 摘要 |
PROBLEM TO BE SOLVED: To improve the alkali pitting corrosion resistance of the subject alloy by dispersing an intermetallic compd. of a specified grain size composed of compositional elements of an Al material into the Al material by specified pieces per unit area. SOLUTION: This invention is an Al alloy in which an intermetallic compd. of 0.5 to 5μm grain size is dispersed by 40000 to 400,000 pieces/mm2 and which is excellent in alkali pitting corrosion resistance. In this case of being immersed into an alkali soln., corrosion in a wide range preferantially occurs to prevent pitting corrosion. At the time of incorporating 3 to 10 wt.% Zn into the Al alloy and immersing it into an alkali soln., defects are made easy to be generated in a film. Moreover, 0.1 to 2 wt.% Mg is incorporated therein to improve the material strength. The cladding material, in which the core material is composed of an Al alloy contg. one or more kinds among the groups of, by weight, 0.05 to 1% Cu, 0.3 to 2% Mn, 0.05 to 1.2% Si and 0.5 to 1.5% Fe and one or more kinds among 0.05 to 0.35 Cr, Ti and Zr, one side is clad with an alkali pitting corrosion resistance Al alloy, and the other side is clad with an Al-Si alloy brazing filler metal, is suitable as the member for a heat exchanger.
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