SURFACE TREATMENT METHOD FOR SUBSTRATE MADE OF ALUMINUM ALLOY FOR HEAT EXCHANGER, AND HEAT EXCHANGER PRODUCED BY USING THE METHOD

摘要

PROBLEM TO BE SOLVED: To provide a surface treatment method with which uniformization and speeding-up in etching treatment for a heat exchanger substrate made of an Al alloy and formation of a corrosion resistant chemical conversion film layer are made possible. SOLUTION: The heat exchanger substrate made of the Al alloy is subjected to pretreatment with an aqueous solution for pretreatment having a pH value of <9.0, is thereafter subjected to etching treatment with an alkaline aqueous solution having a pH value of≥9.0, and is further subjected to chemical conversion treatment/and hydrophilicity application treatment. COPYRIGHT: (C)2005,JPO&NCIPI