The so-called phosphating refers to the method of forming a stable insoluble phosphate film on the surface of metal workpiece by chemical reaction after treatment with acid solution containing phosphate dihydrogen salt. The resulting film is called phosphating film. The main purpose of phosphating film is to increase the adhesion and corrosion resistance of the coating. There are many methods of phosphating. According to the temperature of phosphating, they can be divided into high temperature phosphating (90-98 C), medium temperature phosphating (60-75 C), low temperature phosphating (35-55 C) and room temperature phosphating.

In order to provide a good coating substrate, the phosphating film thickness is suitable, and the crystallization is compact and fine. Although the phosphating process at medium and high temperature is fast and corrosion resistance of phosphating film is good, the crystallization of phosphating film is coarse, the weight of hanging ash is heavy, the liquid level volatilizes quickly, the bath liquid is unstable and there are many sediments. The phosphating film formed by low and normal temperature phosphating process has fine crystallization, suitable thickness, little sediment inclusion between the films, less paint absorption and gloss of the coating. Good degree can greatly improve the adhesion, flexibility and impact resistance of the coating, and can better meet the requirements of the coating for phosphating film. It is worth noting that in the past, it has been considered that the phosphating film is thick and the corrosion resistance of the coating after coating is high. The phosphating film itself does not bear much corrosion resistance in the whole coating system. It mainly plays a role in making the paint film have strong adhesion, while the corrosion resistance of the whole coating system mainly depends on the corrosion resistance of the paint film and the film and the coating. The strong adhesion of phosphating film is formed by the excellent combination of phosphating film and phosphating film.

Conductor automatic vulcanization line

Phosphating solution is generally composed of main salt, accelerator and neutralizer. In the past, sodium nitrite (NaNO2) was mostly used as accelerator for powder coating line, but NaNO2 has great harm in the phosphating solution. First, it affects the stability of phosphating solution. NaNO2 is very unstable under acidic conditions and decomposes in a very short time. Therefore, it has to be added frequently. This characteristic of NaNO2 often leads to unstable main salt of phosphating solution, more precipitation of phosphating solution, serious ash hanging of phosphating film, difficult control of tank fluid and unstable phosphating quality. Secondly, NaNO2 is recognized as a carcinogen in the world, which is harmful to human health for a long time and causes serious environmental pollution. The solution is to reduce the dosage of NaNO2 and to find alternatives.

Formula: XH-1B 4%+H_2O