Etching aluminum or its alloy surface, comprises contacting aluminum surface with hexavalent chromium-free aqueous solution comprising sulfuric acid, nitric acid, ferric sulfate and water at given temperature for specified period of time

摘要

The process of etching a surface of aluminum or its alloy, comprises contacting the aluminum surface with hexavalent chromium-free aqueous solution comprising 275 g/L of sulfuric acid, 100 g/L of nitric acid, 12 g/L of ferric sulfate and water at 50-55[deg] C for 5-10 minutes. The aqueous solution is free from fluorides, and added with a surface active agent (0.3-0.5 vol.%). Independent claims are included for: (1) an aqueous solution for etching an aluminum surface or its alloy; and (2) a process for the treatment of an aluminum surface or its alloy.