Remixed nanometer zinc sulfide tin molybdate conversion liquid for magnesium alloy surface treatment and application method thereof

Abstract

The invention discloses remixed nanometer zinc sulfide tin molybdate conversion liquid for magnesium alloy surface treatment. The conversion liquid selects tin acid salt and sodium molybdate as a main film forming agent, and uses sodium pyrophosphate, sodium fluoride, tannic acid and the like as assistants; nanometer zinc sulfide is added as a corrosion resistant assistance; and terminal carboxyl hyperbranched polyether water solution is used as a medium to obtain an uniform-dispersed nanometer zinc sulfide sol system for effectively preventing agglomeration and precipitation of nanometer materials in the system to achieve efficient modifying effect; the prepared conversion liquid has such advantages as fast film forming speed and high environmental protecting performance; and a conversion film formed on the surface of a magnesium alloy has such advantages as good corrosion resistance and surface compatibility, meanwhile, is unique in photoelectric performance, and further improves the use performance of the magnesium alloy.

Description

technical field [0001] The invention relates to the technical field of magnesium alloy surface treatment, in particular to a tin molybdate conversion solution of complex nano-zinc sulfide used for magnesium alloy surface treatment and a use method thereof. Background technique [0002] Magnesium alloy is a lightweight, high-strength metal material. Products with the same strength can even be lighter than plastics. Its ability to withstand impact loads is greater than that of aluminum alloys. At the same time, magnesium alloys also have good processing performance, fast heat dissipation, Anti-seismic, anti-electromagnetic wave, recyclable and other advantages are widely used in aerospace, 3C products, sports equipment and other fields. Especially in recent years, 3C products have gradually developed in the direction of thinner and shorter, making high-performance magnesium alloys more favored by manufacturers. . [0003] Although magnesium alloys have the above advantages, d...

AI Technical Summary

Problems solved by technology

At present, the commonly used chemical treatment solutions for magnesium alloys mainly include chromate, permanganate, phosphate, permanganate-phosphate and other solution systems. Among them, the process of chromate conversion coating is the most mature, but hexavalent chromium is a high Carcinogens are currently banned from use. Although other types of treatment solutions are more environmentally friendly to a certain extent, the conversion coatings formed have problems such as poor corrosion resistance and cracks in the film layer, which are difficult to meet engineering needs.

In order to improve these defects in the chemical conversion coating, researchers can significantly improve the microstructure of the conversion coating by adding nanoparticles to the conversion solution, as shown in the research results of the article "Influence of Nanohardness on the Microstructure of Chemical Conversion Coating". Nano-Al 2 o 3 , nano-SiO 2 Adding can effectively increase the number of conversion coating grains, increase the density of the conversion coating, and obtain higher corrosion resistance, but improving the dispersion of nano-powders in the conversion solution is still a difficult problem to overcome. High requirements, limited application