METHOD OF BRAZING AN ALUMINUM MATERIAL

摘要

In a method of brazing aluminum material, the flux is formed on the surface of the aluminum material by a chemical conversion coating step. The aluminum material is brought into contact with a treating solution containing potassium and fluorine ions to cause a chemical reaction between aluminum components and potassium and fluorine ions, thereby forming K2AlF5. The K2AlF5 is present on the surface of the aluminum material as a uniform coating and acts as the flux during brazing. With the treating solution further containing zinc, the flux of K2AlF5 and a pitting corrosion inhibiting layer of metallic zinc are simultaneously formed. The treating solution may further include powdered K2AlF5 or AlF3 to increase the amount of flux and thus to intensify the action of the flux. The chemical conversion coating may be applied either to the material to be brazed or to the material for brazing.