Manganese-containing low-zinc light-iron phosphating solution

Abstract

The invention discloses a normal-temperature manganese-containing low-zinc light-iron type phosphating liquid. The phosphating liquid comprising of phosphoric acid, nitric acid, fluorine ion, zinc ion, ammonia ion, sodium nitrate, sodium tungstate, copper nitrate, manganese dihydrogen phosphate, etc., complexing agent, and a plurality of composite oxidizing-reducing agents as well as buffer adjusting agent and so on, wherein, the mass fractions (expressed as g / L) of the compositions are respectively: phosphoric acid( 85 percent) of 8.0 to 29.0, nitric acid( 31 percent) of 2.5 to 6.6, fluorine ion: 0.55 to 3.35, zinc ion: 0.08 to 1.7), ammonia ion: 1.5 to 8.0, sodium tungstate : 0.6 to 4.5, sodium nitrate: 15 to 35, copper nitrate: 0.02 to 0.15, manganese dihydrogen phosphate: 6.0 to 16.5, tartaric acid: 1.5 to 7.22, and methenamine: 0.65 to 1.22. The normal-temperature manganese-containing low-zinc light-iron type phosphating liquid of the invention is used in various large, medium and small sized enterprises in recent years, and has the advantages of mature flow operation, wide process range, less pollution, low comprehensive cost, easy bath solution control, no need of promoters and so on.

Description

technical field [0001] The invention belongs to the metal surface treatment industry before low-carbon copper coating, and is suitable for aerospace, household appliances, electrical switches, instruments and meters, mechanical electronics, automobiles, etc. in order to improve the corrosion resistance, coating adhesion, and enhancement of the metal surface before coating. The field developed for coating gloss. Background technique [0002] The normal temperature phosphating technology is currently the most active in research, the fastest in technological progress, and has broad prospects for development. It overcomes the shortcomings of high and medium temperature phosphating technology, such as high energy consumption, high cost, and low efficiency. The present invention contains manganese at room temperature. The low-zinc light iron type phosphating solution is produced and used by various large, medium and small enterprises in recent years. Therefore, it is generally re...

AI Technical Summary

Problems solved by technology

Among them, iron-based phosphating has the advantages of easy control of the solution, stable bath solution, fast phosphating speed, low solution temperature, less sediment, long service life of the solution, no harmful environmental pollutants, and lower cost than other types of phosphating solutions. Much cheaper, but unsatisfactory corrosion resistance

Zinc phosphating is widely used by most enterprises because of its uniform and fine film layer, good decorative performance, strong adhesion to the coating, relatively stable phosphating film layer, and good corrosion resistance. However, the operators of the factory are often at a loss. In addition, the steel surface conditions in the domestic steel market are different (the rolling oil used and its material are very different), and because the phosphating solution market currently has no unified management, the technical operation standardization is lacking. Due to the limited production conditions of enterprises, it is inevitable to cause a series of disadvantages such as inconsistent process specifications. Therefore, it is necessary to propose a more standardized phosphating operation process, production process, and select a phosphating solution with better performance. the basis of

Because in the past, people only emphasized the corrosion resistance of the phosphating film itself, while ignoring the supporting performance of the phosphating film and the coating, so that the thickness of the phosphating film layer was required one-sidedly. In fact, the phosphating film itself does not bear too much corrosion resistance. Corrosion effect, whether the matching performance between him and the coating is good is the key to affect the entire coating system. The medium and high temperature phosphating film is coarse and brittle, with high porosity and high resistance, which is not conducive to the uniform distribution of the electric field on the workpiece, so it is not suitable for For electrophoretic coating and electrostatic plastic spraying, in order to enhance the conductivity, the phosphating film is required to be thin and dense, with low porosity, film weight of 1-4g / m, and film thickness of 1-2μm. The process is a new type of phosphating solution developed to overcome the shortcomings of other types of phosphating solutions. It overcomes the shortcomings of the above phosphating solutions, so it has great prospects for development