Phosphorus-free film forming agent and preparation method thereof

Abstract

The invention relates to a phosphorus-free film forming agent comprising the following components by weight percent: 0.5-4 percent of silane coupling agent, 0.5-2 percent of titanate coupling agent, 1-10 percent of fluozirconate or zircon salt, 3-5 percent of alcohol solvent, 0.5-2 percent of hydrofluoric acid or fluorid, 1-5 percent of hydrogen peroxide, 0.5-2 percent of notric acid or nitrate and the balance of deionized water or tap water. The phosphorus-free film forming agent is environment-friendly and can increase adhesive force and corrosion resistance.

Description

technical field [0001] The invention relates to a phosphorus-free film-forming agent and a preparation method thereof, belonging to the technical field of metal coating pretreatment. Background technique [0002] Traditional metals, especially steel, cast iron and their alloys, include three parts before painting: oil removal, rust removal, and phosphating, among which phosphating is the central link. Phosphating is the process of chemical and electrochemical reactions to form a phosphate chemical conversion film. The formed phosphate conversion film is called a phosphating film. The purpose of metal phosphating is mainly to provide protection for the base metal, to a certain extent prevent the metal from being Corrosion: Used for pre-painting treatment to improve the adhesion and anti-corrosion ability of the paint film layer. However, the phosphating treatment solution is composed of phosphoric acid, phosphate, nitrate, heavy metal ions and oxidants, which pollute the env...

AI Technical Summary

Problems solved by technology

However, since the film layer formed by the Si-O-Me covalent bond between the metal substrate and the organic silicon is a single organic component, it cannot electrochemically protect the metal surface, so the anti-corrosion performance of the treated film layer needs to be improved.

Secondly, due to the influence of the higher surface of the metal oxide and the polycondensation reaction after the hydrolysis of the metal silane coupling agent, it will reduce the number of Si-O-Me covalent bonds formed between the treatment liquid and the metal surface, and cannot form high-quality Therefore, the adhesion of the metal treatment layer, especially the continuous adhesion, is not good enough, so the adhesion and anti-corrosion ability of this treatment method cannot completely replace the traditional phosphating method.