ALUMINUM ALLOY MEMBER WITH EXCELLENT JOINABILITY TO RESIN, AND PROCESS FOR THE PRODUCTION THEREOF

摘要

Provided is an aluminum alloy part which has an extremely complicated surface profile and thus exhibits an enhanced joinability to a resin member. The aluminum alloy part is an Al alloy member obtained by subjecting a cast member of an Al-Si based alloy to surface chemical etching with an acid fluid. The Al alloy member has multiple recesses over part or the whole of the surface; and the recesses have a mean opening width of 0.1 to 30µm, each recess having multiple protrusions consisting of a eutectic Si crystal on the inside surface. The protrusions consisting of a eutectic Si crystal have sizes of 0.1 to 10µm in terms of sphere-equivalent particle diameter, while portions where only Si is distributed account for 5 to 80% of the total of the eutectic portions as determined by elemental analysis for Si and Al by X-ray fluorescence mapping.