| 摘要 |
826,494. Preventing corrosion. PETROCOKINO, D. D. Sept. 5, 1956 [Sept. 8, 1955; Oct 14, 1955], No. 27094/56. Class 123(1) Corrosion cf metal surfaces such as the interior surfaces of ship's ballast tanks is prevented by first passivating the surface by forming thereon a porous, crystalline layer by treatment with a phosphating medium containing non-saponifiable resins which are irreducible by hydrogen and subsequently preventing corrosion by cathodic protection. The phosphating agent may be an aqueous solution of phosphoric acid, zinc phosphate or manganese phosphate mixed with a resin such as vinyl copolymers, polystyrene or polyethylene and an inhibitor such as a chromate, vanadate or tungstate may be added. The formation of the porous phosphate film may be accelerated by addition to the seawater ballast of milk of lime with or without a wetting agent, a reducing agent such as sodium sulphite and a magnesium containing substance such as dolomite. The subsequent cathodic protection is provided by sacrificial anodes of magnesium, zinc or aluminium alloy. |
