Normal-temperature trivalent chromium iridescent passivation solution, preparation method and using method thereof

Abstract

The invention provides a normal-temperature trivalent chromium iridescent passivation solution. The normal-temperature trivalent chromium iridescent passivation solution comprises, by weight, 0.6%-0.8% of chromic nitrate, 0.3%-0.5% of citrazinic acid, 0.3%-0.5% of sodium tungstate, 0.025%-0.03% of nickel chloride, 0.06%-0.08% of acetic acid and the balance water. A passivation film obtained through the method is good in corrosion resistance, a salt spray test can reach 1200h or above, the surface of a workpiece is free of any white rust or white spot, the porosity is low and no sealing agent is required for treatment.

Description

technical field [0001] The invention relates to the field of metal surface treatment agents, more specifically, to a normal temperature trivalent chromium color passivation solution, a preparation method and a use method thereof. Background technique [0002] The galvanized layer is one of the most important protective coatings for steel parts. The galvanized layer is very stable in a dry environment, but in a high-temperature and high-humidity environment, the galvanized layer has poor corrosion resistance and is prone to white rust or white spots ; Generally, a high-concentration or medium-concentration chromate solution is used for passivation to improve the corrosion resistance of the galvanized layer. [0003] Hexavalent chromium passivation is the most widely used passivation process at present, but the hexavalent chromium compound in the hexavalent chromium passivation solution is highly toxic and carcinogenic, which seriously pollutes the environment and has a great ...

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Problems solved by technology

[0003] Hexavalent chromium passivation is the most widely used passivation process at present, but the hexavalent chromium compound in the hexavalent chromium passivation solution is highly toxic and carcinogenic, which seriously pollutes the environment and has a great impact on the health of workers. In the production process, as well as in the subsequent wastewater and waste residue treatment process, there will be great unsafe factors; therefore, it is necessary to find a passivation process with low toxicity and performance close to the hexavalent chromium passivation solution to replace the hexavalent chromium passivation solution. Trivalent chromium passivation has similar properties to hexavalent chromium passivation in many aspects, but the toxicity is only 1% of hexavalent chromium, which is the most likely acceptable substitute for hexavalent chromium passivation. widespread concern of researchers