| 摘要 |
PURPOSE:To form the film of a rust inhibitor on the surface of copper parts inexpensively and economically, by a method wherein the copper parts of an engine cooling system immersed in an aqueous solution of the rust inhibitor comprising a heterocyclic compound containing a N atom is used as an anode and voltage is applied thereto. CONSTITUTION:The aforementioned rust inhibitor aqueous solution 4 is accommodated in a tank 2 and the aforementioned copper parts 8 is immersed in said aqueous solution 4 as an anode. In the next step, voltage is applied between the anode 8 and a cathode 10 to form the film of the rust inhibitor on the surface of the anode 8. The aqueous solution 4 contains water as a main component and is held to such conditions that the concn. of benzotriazole as the rust inhibitor is adjusted to 0.1-5.0wt%, pH due to the dripping of hydrochloric acid to 2.5-3.5, a liquid temp. especially to a room temp. and the voltage of a power source to 5-20V. As the rust inhibitor, other than benzotriazole, mercaptobenzothizole or tolyltriazole can be used. |
