A kind of highly corrosion-resistant trivalent chromium blue-white passivation concentrated solution and preparation method thereof

Abstract

The invention discloses high-corrosion-resistance trivalent chromium blue white passivation concentrated solution. The passivation solution comprises the following raw materials and contents: 100-350 g / L of chromic salt, 50-250 g / L of cobalt salt, 50-200 g / L of complexing agent, 50-200 g / L of oxidizing agent, and 10-120 g / L of pH conditioning agent; and solvent is water. The passivation concentrated solution adopts the most advanced international trivalent chromium, contains no hexavalent chromium, belongs to the new generation of environment-friendly product, and is simple in process operation, easy to operate and control, excellent in stability, uniform and bright in blue of a passivation membrane, compact and firm in film formation, higher in corrosion and collision resistance and meanwhile, longer in service life.

Description

technical field [0001] The invention belongs to the technical field of metal surface treatment and protection, in particular to a highly corrosion-resistant trivalent chromium blue-white passivation concentrate and a preparation method thereof. Background technique [0002] With the development of industrial technology, higher and higher requirements are put forward for the performance of material surface. As a protective coating, zinc-nickel alloy has excellent properties such as low hydrogen embrittlement, good weldability and machinability, and is widely used in industrial fields such as automobiles, motorcycles, and daily hardware. However, in the natural state, the zinc-nickel alloy is difficult to resist the harm of common corrosion, which seriously affects the performance of the product. In order to improve the quality and service life of zinc-nickel alloys, surface passivation treatment is usually carried out, and chromate passivation treatment is a common method to...

AI Technical Summary

Problems solved by technology

[0004] At present, there are some defects in the blue-white passivation process of zinc-nickel alloy trivalent chromium, such as uneven blue color after passivation treatment, easy yellowing or purplish red, and unstable appearance; the working pH value of the passivation solution is low, generally Maintained at about 2.5, the lower pH value makes the zinc and iron impurities in the passivation solution rise faster, thereby reducing the service life of the passivation solution; the neutral salt spray test of the passivation layer is not long, as in the patent No. The trivalent chromium blue-white passivation technology mentioned in CN 103866309A, the white rust resistance time of the passivation layer is about 96h, and the passivation process is not easy to control, etc.