Method for producing alumina-crystal-particle-dispersed alumina sol, alumina-crystal-particle-dispersed alumina sol obtained by the method, and aluminum coated member produced using the sol

摘要

An aluminum salt is dissolved into water as a solvent to prepare an aqueous solution of the aluminum salt. Urea is added to the aqueous solution of the aluminum salt to be dissolved into the solution. The solution is heated to produce a precipitation of aluminum hydroxide. A deflocculant is added to deflocculate the precipitation. Thus, a sol is produced which contains colloidal particles of aluminum hydroxide and crystalline particles of aluminum oxide. An even and dense alumina thin film can be produced by using the sol on a surface of a substrate made of a metal having a low melting point, such as copper or aluminum.