| 摘要 |
PURPOSE:To provide the titled low-pollution corrosion preventing liq. having a sufficient corrosion preventing effect and contg. specified amounts of phosphoric acid, polyphosphoric acid or a salt thereof, molybdic acid, tungstic acid, vanadic acid, a salt thereof or a heteropolyacid salt of Mo, W or V, and benzotriazole, tolyptriazole or a salt thereof. CONSTITUTION:This corrosion preventing liq. contains 500-30,000ppm of >=1 kinds among component (1) selected from phosphoric acid, polyphosphoric acid and salts thereof, 50-500ppm of >=1 kinds among component (2) selected from molybdic acid, tungstic acid, vanadic acid, salts thereof and heteropolyacid salts of Mo, W and V, and 5-500ppm of >=1 kinds among component (3) selected from benzotriazole, polyltriazole and salts thereof. It is known that each of the components 1-3 has a corrosion preventing effect on a specified metal. By blending the components 1-3 at said concns., the corrosion of a Cu-solder-Al contact system as well as a stee-cast iron-Al contact system can be prevented thoroughly. The preventing liq. also inhibits the corrosion of the heating surface of Al. |
