Preparation method of normal-temperature brush-coating phosphating solution for household appliances

Abstract

The invention discloses a preparation method of a normal-temperature brush-coating phosphating solution for household appliances. The preparation method comprises the following steps: 1) 10-12 g/L of zinc oxide is added into a small amount of water and a paste is made; half of the total amount 44-48 g/L of phosphoric acid is added and stirred until phosphoric acid is dissolved; 2) 6-8 g/L of calcium oxide is added into a small amount of water and a paste is made; the other half of the phosphoric acid is added and stirred until the phosphoric acid is dissolved; 3) solutions from the step 1) and the step 2) are mixed and uniformly stirred, 24-28 g/L of zinc dihydrogen phosphate, 16-20 g/L of monocalcium phosphate, 6-8 g/L of tartrate, 5-7 g/L of sodium citrate, 12-14 g/L of oxalic acid, 3-6 g/L of hydroxylammonium hydrogensulphate, 7-9 g/L of nickel fluoride, 6-8 g/L of nickel sulfate, 3-5 g/L of OP-10 and 2-4 g/L of sodium dodecanesulphonate are successively added and uniformly stirred, and water is finally added for a constant volume so as to obtain the phosphating solution.

Description

technical field [0001] The invention relates to the technical field of surface treatment, in particular to a method for preparing a normal-temperature brush-coating phosphating solution for household appliances. Background technique [0002] Phosphating treatment is one of the chemical protection methods for ferrous metals. With the rapid development of household appliances, phosphating process has been widely used, but the phosphating treatment temperature of the original phosphating solution is generally above the medium temperature of 35 ° C, and because the phosphating solution It is an acidic medium, and it has a strong corrosive effect on phosphating equipment and heating equipment at a temperature above the middle temperature. Generally, the equipment must be replaced within two years. At the same time, due to the need for heating, the energy consumption is large, which is not conducive to energy conservation. [0003] In Chinese patent CN1032963A, a kind of phosphate...

AI Technical Summary

Problems solved by technology

[0002] Phosphating treatment is one of the chemical protection methods for ferrous metals. With the rapid development of household appliances, phosphating process has been widely used, but the phosphating treatment temperature of the original phosphating solution is generally above the medium temperature of 35 ° C, and because the phosphating solution It is an acidic medium, and it has a strong corrosive effect on phosphating equipment and heating equipment at a temperature above the middle temperature. Generally, the equipment must be replaced within two years. At the same time, due to the need for heating, the energy consumption is large, which is not conducive to energy conservation.

[0003] In Chinese patent CN1032963A, a kind of phosphate solution for dipping and phosphating is disclosed, which contains zinc ion 1-3 g / liter, calcium ion 1.0-4.5 g / liter, phosphate ion 21-32 g / liter, Sodium m-nitrobenzenesulfonate 0.1-3 g / L, chlorate ion 0.3-10 g / L, nitrate ion 0-15 g / L, nickel ion 0.1-0.3 g / L, disodium edetate 0.08-0.15 g / L, manganese ion 0-0.8 g / L, wherein the ratio of zinc to calcium ion is 1:1-1.5, the ratio of zinc to phosphate ion is 1:7-19, m-nitrobenzenesulfonic acid The ratio of sodium to chlorate ions is 1:1-3.5, and its characteristic is that the film-forming material is mainly zinc calcium phosphate, using sodium m-nitrobenzenesulfonate, chlorate, and nitrate ions as joint accelerators, and other ions As an additive; the disadvantage of this solution is that when sodium m-nitrobenzenesulfonate is used in combination with nitrate ions, the solution will turn yellowish brown when the concentration of sodium m-nitrobenzenesulfonate is not well controlled. When sodium is used as an accelerator, the concentration of sodium chlorate is not easy to control. When it is too much, the solution will be poisoned, resulting in partial passivation of the steel surface, which will bring unfavorable factors to the formation of the phosphating film; It needs to be heated to a medium temperature of 58°C before phosphating, which has a strong corrosive effect on phosphating equipment and heating equipment, and consumes a lot of energy and has a lot of sludge

[0004] In the Chinese patent CN1037936A, a "phosphating solution and its preparation method" is disclosed, which consists of two parts: pickling solution and phosphating solution. %, sodium dodecylsulfonate 0.05-0.15%, Pingpingjia 0.05-0.15%, cetyltrimethylamine chloride 0.05-0.15%, citric acid 1-10%, water 93.145-39.535%; phosphating solution The percentage group is calcium nitrate 5-15%, zinc phosphate 5-15%, nickel nitrate 0.15-0.25%, cobalt nitrate 0.045-0.55%, tin nitrate 0.045-0.055%, citric acid 0.15-0.25%, tartaric acid 0.045- 0.055%, E.D.T.A6.045-0.055%, surfactant OP0.008-0.002%, water 89.512-69.26%; its main feature is that the metal is pickled first, and then phosphating at 65-70°C. Its disadvantage is that pickling the metal in strong inorganic acid will bring defects to the formation of phosphating film, and the phosphating speed is slow, and it also needs to be heated, which has the same disadvantages of the above-mentioned prior art