Normal-temperature phosphating agent for pre-processing before spray-coating of steel plate workpiece and preparation method thereof

Abstract

The invention relates to a normal-temperature phosphating agent for pre-processing before spray-coating of steel plate workpiece, containing the following raw materials in percentage by mass: 12-46% of phosphoric acid with concentration of 85%, 2-9% of nitric acid with concentration of 98%, 6-18% of zinc oxide, 0.2-2.8% of hydrofluosilicic acid with concentration of 40%, 0.1-3.3% of hydrofluoric acid, 0.5-5.5% of nickel nitrate, 1-4% of potassium chlorate, 0.1-1.0% of citric acid, 0.1-0.6% of ferric nitrate, 0.1-0.15% of silicofluoric acid and the balance of tap water. The preparation method comprises the steps as follows: first, adding 1 / 3 tap water in a reaction kettle and stirring at normal temperature and normal pressure; adding 85% phosphoric acid and 98% nitric acid in sequence, adding nickel nitrate and zinc oxide, stirring for complete dissolution, continuously adding potassium chlorate and hydrofluosilicic acid with concentration of 40%, then adding silicofluoric acid, hydrofluoric acid, citric acid, ferric nitrate and rest 2 / 3 tap water, stirring until the solution becomes green and transparent liquid; sampling, analyzing, filling and packing. The pre-processing before spray-coating of steel plate workpiece phosphating agent by the phosphating agent can be carried out at normal temperature so that the whole chemical processing process is simple, the operation is convenient, the heating device is saved, and the production cost is reduced. The preparation method has simple process and is easy for control and operation.

Description

technical field [0001] The invention relates to a phosphating agent and a preparation method thereof, in particular to a normal temperature phosphating agent and a preparation method thereof for pre-spray coating of steel plate workpieces Background technique [0002] Steel workpieces generally undergo chemical treatment before spraying and coating to form a protective film on the surface. The main functions of this protective film are: one is to improve the overall anti-corrosion performance of the coating, and the other is to strengthen the substrate of steel workpieces. The adhesion between the sprayed coating and the sprayed coating is due to the porosity and relative roughness of this layer of protective film, which allows the coating to penetrate into the pores to achieve the tight combination of the sprayed coating layer and the protective film, and the effect of improved adhesion Purpose. [0003] At present, phosphating technology is used for chemical treatment. Wh...

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