Preparing method for nano titanium dioxide doped normal-temperature environment-friendly composite phosphating film

Abstract

The invention discloses a preparing method for a nano titanium dioxide doped normal-temperature environment-friendly composite phosphating film. 5.0-7.0 g of analytically pure zinc oxide is taken, a small amount of deionized water is added, and the analytically pure zinc oxide is stirred to be pasty; 15-25 mL of analytically pure phosphoric acid is added, and sharp stirring is conducted till a solution is clear, the solution being called No. 2 solution; 3.8-4.2 g of dissolved citric acid is added into the No. 2 solution, and sufficient stirring is conducted to obtain a No. 3 solution; 1.8-2.2g of potassium chlorate, 0.4-0.6 g of ammonium molybdate and 0.55-0.65 g of sodium m-nitrobenzene sulfonate are taken, after being completely dissolved through deionized water, the potassium chlorate,the ammonium molybdate and the sodium 3-nitrobenzene sulfonate are added into the No. 3 solution, and sufficient stirring is conducted to obtain a No. 4 solution; 0.25-0.35 g of 2-hydracrylic acid isweighed and is slowly dropwise added into the No. 4 solution under stirring to obtain a No. 5 solution; 0.5-0.8 g of sodium fluosilicate is added into the No. 5 solution to obtain a No. 6 solution, 50-150 ml of nano TiO2 suspension liquid is added into the No. 6 solution for mixing in a stirring state, so that a phosphating solution is obtained; and a cold-rolled low-carbon steel workpiece or sample with the cleanly-treated surface is placed in the phosphating solution to be subjected to normal-temperature phosphorization for 7-10 min, and a layer of grey black uniform and dense phosphating film is formed on the surface of the cold-rolled low-carbon steel workpiece or sample. The composite phosphating film in which nano TiO2 participates in the film forming is developed, energy saving andenvironment friendliness are achieved, and the ecological environment is protected.

Description

Technical field [0001] The invention belongs to the technical field of surface treatment of cold-rolled low-carbon steel parts, and in particular relates to a method for preparing a normal temperature environmentally friendly composite phosphating film doped with nanometer titanium dioxide. Background technique [0002] Cold rolled steel, because of its good physical and mechanical properties, is widely used in the manufacture of automobiles, home appliances, industrial equipment and engineering machinery. It is still the mainstream of automotive sheet steel. Among automotive steel sheets, the current hot Rolled plates account for about 20%, and cold rolled plates account for about 80%. But cold-rolled steel, like other metal materials, has serious corrosion. According to statistics from developed countries, the annual loss caused by metal corrosion accounts for more than 4% of its GDP. In order to reduce losses and save resources, countries around the world adopt different meth...

AI Technical Summary

Problems solved by technology

At present, the phosphating treatment of automobile steel sheets in domestic and foreign automobile production lines still generally adopts Zn-containing 2+ , Mn 2+ 、Ni 2+ This kind of phosphating method contains heavy metal ions, the treatment temperature is high, the energy consumption is large, and the amount of sediment is large; although normal temperature phosphating has been widely used, its accelerators are still nitrite and nickel. Ion-based, producing toxic gas, polluting the environment, and also has the disadvantages of high sediment and poor corrosion resistance

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