Method of surface treating aluminum alloy base body of heat exchanger and heat exchanger produced by the method

摘要

A method of surface treating an aluminum alloy base body of an heat exchanger which method enables an etching procedure to be carried out uniformly and quickly and a corrosion-resistant chemical conversion coating to be formed, is effected by pretreating the Al heat exchanger base body with an aqueous pre-treating liquid having a pH of 9.0 or less, etching the pretreated base body with an aqueous alkaline solution having a pH of 9.0 or more, and then subjecting the etched base body to a chemical conversion treatment or a hydrophilicity-enhancing treatment.