| 摘要 |
PURPOSE:To avoid the generating of harmful gas in a period of the purification of a metallic material and to allow the performance to be held even after the elapse of a long period after the formation of a film by purifying the surface of the metallic material with a ferric chloride soln. prior to the molding of it and thereafter forming a specified mineral chemical conversion film. CONSTITUTION:A wire rod 1 of stainless steel, Ni alloy and Cu alloy or the like is immersed in an FeCl3 soln. being a surface preparation liquid incorporated in a treatment vessel 2 at ordinary temp. and simultaneously air is blown in the soln. to feed O2. Thereby oxide on the surface of the wire rod 1 is eluted in the above-mentioned soln. and the metal of the wire rod 1 is not eroded by FeCl2. Also since Cl2 generated in the reaction shown in an equation I by means of a catalytic action of the above- mentioned O2 is allowed to react like equation II, the generation of Cl2 is not caused. After washing immediately the wire rod 1 drawn up from the above-mentioned soln. with ordinary temp.-water (5-7pH) in a water-washing tank 3, it is immersed in a soln. incorporated in a reaction tank 4. This soln. consists of both one or more kinds of sodium molybdate, sodium titanate, sodium tungstate, sodium borate and sodium silicate. Thereby the mineral chemical conversion film is formed on the surface of the wire rod 1. |
