In the car evaporator which was assembled by the aluminum material null wax attaching for the heat exchanger which rustproofing manner and

摘要

PROBLEM TO BE SOLVED: To provide a rust preventive treatment system for an aluminum material for a heat exchanger which forms a good chemical conversion film by removing the segregated matter existing on the surfaces of the fines and tubes of an aluminum heat exchanger to clean these surfaces and is capable of enhancing corrosion resistance and the adhesion property to a hydrophilicity impartation treatment film even in the case micro defects exist on the chemical conversion film and an aluminum material for the heat exchanger subjected to a rust preventive treatment.;SOLUTION: The aluminum material for the heat exchanger is subjected to the rust preventive treatment by the following stages: (1) the acid washing stage for bringing an acidic detergent consisting of an aqueous solution containing 0.01 to 5 mass % at least one kind of the metal salt and/or metal acid salt selected from iron, nickel, cobalt, molybdenum and cerium and nitric acid and/or sulfuric acid into contact with; (2) the chemical conversion treatment stage for forming the chemical conversion film after the acid washing stage; and (3) the post treatment stage for bringing a silane coupling treatment into contact with the aluminum material after the chemical conversion treatment and thereafter the hydrophilicity impartation treatment stage for forming the hydrophilic film by a hydrophilic coating material.;COPYRIGHT: (C)2001,JPO