Surface treating agent for metal member

摘要

A surface treating agent for a metal member comprising an aqueous mixed acid solution prepared from oxalic acid and an inorganic acid; a method and an apparatus for carrying out the surface treatment of a metal member using the agent; and a method and an apparatus for carrying out the surface treatment of a metal member by circulating an oxalic acid based treating solution. The surface treating agent for a metal member is based on oxalic acid and also can be effectively used for an application involving dissolution of iron (II).