Environment-friendly blue-white passivation liquid and preparation method thereof

Abstract

The invention discloses environment-friendly blue-white passivation liquid and a preparation method thereof, and belongs to the technical field of metal material surface treatment. The passivation liquid comprises the components of 4-8 g / L of sodium silicate, 23-27 g / L of sodium nitrate, 1-5 g / L of nickel sulfate, 3-7 mL / L of titanium trichloride, 8-12 mL / L of hydrogen peroxide, 3-7 g / L of succinic acid, 0.35-0.45 g / L of benzylidene acetone, 1-3 g / L of thiourea and the balance deionized water, and the pH value is 0.5-1.5. The preparation method of the passivation liquid comprises the steps that the sodium silicate is dissolved in the deionized water; then the sodium nitrate, the nickel sulfate, the titanium trichloride, the hydrogen peroxide, the succinic acid, the benzylidene acetone andthe thiourea are sequentially added and evenly mixed; the deionized water is added to conduct constant volume to the required volume; and sulfuric acid is adopted to adjust the pH value to be 0.5-1.5,and then the silicate blue-white passivation liquid is obtained. A zinc coating passivation film treated through the passivation liquid is blue white, the color is bright, film forming is uniform, corrosion resistance is excellent, the passivation liquid does not contain trivalent chromium, hexavalent chromium and other harmful substances, environmental protection is achieved, pollution is avoided, the passivation process is simple, the passivation efficiency is high, and the film layer corrosion resistance is good.

Description

technical field [0001] The invention relates to an environment-friendly blue-white passivation solution and a preparation method thereof, belonging to the technical field of metal material surface treatment. Background technique [0002] Electroplating is indispensable in the field of metal material protection. Electroplating is the use of electrolysis to form a uniform, dense, and well-bonded metal or alloy deposition layer on the surface of the workpiece to separate the protected workpiece from the corrosive medium, thereby achieving anti-corrosion effects. This method of material protection is simple to operate, and the equipment Inexpensive and therefore widely used. However, if the coating is not well post-treated, the surface of the coating will soon become dark, and white corrosion products will appear one after another, thus failing to achieve the effect of protecting the workpiece. Therefore, in order to improve the corrosion resistance of the parts, passivation t...

AI Technical Summary

Problems solved by technology

The molybdate system has a good effect of delaying corrosion and low toxicity, but the thickness of the passivation layer is too high, and the cost is also high; the trivalent chromium system, which is a heavy polluting metal, will cause damage to the environment. Not in line with my country's national conditions, the application prospects are not good

[0004] The patent application document "A Silicate Blue-White Passivation Solution and Its Preparation Method" with the application number 201710618017.7 provides a silicate blue-white passivation solution, which contains sodium fluoride Substances, sodium fluoride reacts with acids to produce corrosive and more irritating hydrofluoric acid, which is highly corrosive and pollutes the environment