SURFACE TREATMENT OF ALUMINUM ALLOY MATERIAL

摘要

PURPOSE:To attain to enhance the close adhesiveness of a coating, by performing the surface treatment of a ground coat by removing an insoluble compound formed after an Al-alloy material is subjected to degreasing or etching treatment with a solution of a metal ion sequestrant. CONSTITUTION:A fragile insoluble compound such as Mg re-precipitated on the surface of an Al-alloy material containing Mg after the degreasing and/or etching treatment of said Al-alloy material is removed by a solution of a metal ion sequestrant such as polyphosphate to enable the formation of a coating having high close adhesiveness in the succeeding coating process.