FIN FOR HEAT EXCHANGER HAVING EXCELLENT WETTABILITY AND ITS MANUFACTURE

摘要

PURPOSE:To obtain a fin for a heat exchanger having the excellent wettability and oil contamination resistance by forming a hydrated oxidized film excellent in wettability on the surface of an Al material and forming successively silicic acid compd. and inorganic phosphoric acid compd. on this surface. CONSTITUTION:A hydrated oxidized film excellent in wettability is formed on the surface of an Al material by treating the Al (alloy) material with a chloric soln. incorporated with an oxidizing agent. After rinsing, about 0.025g/m<2> silicic acid compd. expressed in terms of silicic acid is formed on this surface. Then about 0.005g/m<2> inorganic phosphoric acid compd. expressed in terms of phosphoric acid is formed by coating an inorganic phosphate soln. such as sodium tripolyphosphate and drying it with a hot air. Thereafter a fin for a heat exchanger is obtained by performing the prescribed molding work and the degreasing treatment. By this process, the wettability and the durability of the fin are increased.