A method for preparing composite phosphating film by doping inorganic nanoparticles

Abstract

The invention discloses a method of preparing a composite phosphating film by doping inorganic nanoparticles. The method comprises the following steps that the components of, by mass 5-8 parts of phosphate, 7-9 parts of zinc, manganese or calcium salt, 0.6-3 parts of phosphoric acid, 0.04-0.4part of boron nitride, 0.1-1 part of a stabilizer, 6-10 parts of a pH buffer agent, 80-100 parts of water are put into a reaction kettle, and the pH value is adjusted to 2-3 by using an alkali solution, then temperature is heated to 20-40 DEG C, and mechanically stirring and discharging kettle are carriedout; and then a prepared phosphating treatment solution is placed into a phosphating tank, the temperature of the phosphating treatment is increased to 20-40 DEG C, then a steel test piece after rustremoval and oil removal is immersed into the phosphating tank, and after the steel test piece is treated, the steel test piece is washed by water and aired. According to the method, the boron nitrideis used as a nucleation adsorption site of crystal during phosphorization, so that crystal adhesion is facilitated, and a composite phosphating film is formed, the boron nitride is a hydrophobic nanomaterial, the dense composite phosphating film can effectively prevent the permeation of the water in air, and corrosion resistance is excellent.

Description

Technical field [0001] The invention relates to a phosphating film, in particular to a method for preparing a phosphating film by doping nano boron nitride; it belongs to the field of material science and surface technology. Background technique [0002] After the metal surface is degreasing and derusting, in order to prevent re-rusting, chemical treatment is usually carried out to form a protective film on the metal surface. Phosphating is a commonly used surface treatment technology, which refers to the process of forming a hardly water-soluble phosphate film on the metal surface through a chemical reaction in a specific acid phosphate solution. According to the type of phosphating film, phosphating can be divided into six categories: zinc series, zinc calcium series, zinc manganese series, manganese series, iron series, and amorphous iron series. It should be pointed out that although the phosphating film is thin, because it is a non-metallic non-conductive isolation layer, i...

AI Technical Summary

Problems solved by technology

[0003] At present, the phosphating treatment at home and abroad is mostly used in medium and high temperature phosphating, which not only consumes a lot of energy, takes a long time to process, and has a lot of sediment, but also needs to be closed after phosphating. The process is relatively complicated, which directly affects the coating production quality, yield and cost of

For the phosphating of steel specimens, there are problems such as not being environmentally friendly, the phosphating solution is unstable, and the quality of the phosphating film is poor.

It can be seen that the traditional phosphating process is very time-consuming and energy-consuming.

[0004] Chinese invention patent CN200610045653.7 discloses a technology that uses nano-alumina to promote phosphating. Although the phosphating process only takes 9 to 12 minutes and the prepared phosphating film has better wear resistance, the temperature needs to be 50 ~90°C, comparatively energy-consuming

Moreover, the phosphating film grains are not dense, and the anti-corrosion performance needs to be improved.

[0005] The Chinese invention patent application with the application number CN201610397553.4 discloses a formula for carbon steel pipe phosphating solution at room temperature. Although this formula can quickly carry out phosphating treatment of workpieces at close to room temperature, it uses toxic and harmful nitrous acid. Sodium and sodium fluoride are used as accelerators, and the dosage is relatively high. The three wastes generated are difficult to treat and do not meet the needs of environmental protection.

[0006] The Chinese invention patent application with the publication number CN101029386A discloses a calcium-zinc-manganese ternary cationic phosphating solution for the treatment of steel plates and galvanized sheets, although the phosphating solution has fast film formation and good compatibility with electrophoretic coatings advantages, but the concentration of the phosphating solution is high, the cost is high, and the working temperature is 40-60°C, which consumes more energy

[0007] The Chinese invention patent application with the application number CN103469187A discloses a treatment solution for phosphating and blackening the surface of steel. Although the temperature of the treatment solution is normal temperature and the corrosion resistance and film quality of the treated steel surface are better, However, the phosphating process is slow and takes 30 to 50 minutes, which is time-consuming

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