Preparation method of trivalent chromium black zinc passivation solution

Abstract

The invention discloses a preparation method of a trivalent chromium black zinc passivation solution. The preparation method comprises the following steps that a raw material for preparing the passivation solution is weighed and prepared; trivalent chromium compound, stearic acid, cobalt nitrate, hydrochloric acid and nitric acid are added into a stirrer, and a mixed solution A is obtained throughstirring and mixing; sodium chloride and water glass are added into deionized water, and a mixed solution B is obtained through dissolving after stirring and mixing; and the mixed solution A and themixed solution B are added into a dispersing machine together with a weighed anionic surfactant, and trivalent chromium black zinc passivation solution is obtained through dispersing and uniformly mixing. According to the preparation method of the trivalent chromium black zinc passivation solution, the trivalent chromium compound is adopted as the main raw material, the solution contains no hexavalent chromium compound at all, and the method accords with the national safety and environmental protection concept; the preparation method is simple, the preparation cost is low, and the obtained trivalent chromium black zinc passivation solution is convenient to use and can be passivated at normal temperature, and the passivation efficiency is high; and the surface of the obtained black passivation film is smooth, the compactness is good, the binding force is strong, the wear resistance of the film layer is improved, the corrosion resistance is high, and the method is capable of being widelyapplied to surface passivation of galvanized metal, the effect is durable and the popularization is worthwhile.

Description

technical field [0001] The invention relates to the technical field of metal passivators, in particular to a preparation method of a trivalent chromium black zinc passivation solution. Background technique [0002] The traditional hexavalent chromium passivation process has the advantages of maturity and stability, low price, variety, high corrosion resistance and self-healing ability of passivation film, and has been widely used. However, hexavalent chromium is a strong carcinogen, which will cause serious harm to the environment and human health. Therefore, the research on the hexavalent chromium-free passivation process has become the focus. The research on the hexavalent chromium-free passivation process in my country mainly focuses on two aspects: chromium-free passivation and trivalent chromium passivation. It has poor corrosion resistance and has not been used in industrial production; therefore, my country's hexavalent chromium-free passivation technology mainly reli...

AI Technical Summary

Problems solved by technology

However, the trivalent chromium black zinc passivation solution in the prior art has defects such as large consumption, low passivation efficiency, and the density and hardness of the obtained passivation film are not up to standard due to the limitations of the formula and process.