What is pickling phosphating?

Pickling and phosphating treatment is a process of forming phosphate chemical conversion film through chemical and electrochemical reactions, which is called phosphating film.

Phosphating is a common pretreatment process, which belongs to chemical conversion film treatment in principle. It is mainly used for phosphating steel surface, and non-ferrous metals (such as aluminum and zinc) can also be used for phosphating. The main purpose of phosphating is to provide protection for the base metal and prevent the metal from being corroded to a certain extent; Used for priming before painting to improve the adhesion and corrosion resistance of paint film; It plays an anti-friction and lubrication role in the cold working process of metal.

Extended data:

Phosphating treatment requires that the surface of the workpiece should be a clean metal surface (except for two-in-one, three-in-one and four-in-one). Before phosphating, the workpiece must be degreased, derusted, derusted and surface adjusted. Especially, before painting, the primer is phosphatized, and surface adjustment is needed to make the metal surface have certain "activity" to obtain a uniform, detailed and dense phosphating film, which meets the requirements of improving the adhesion and corrosion resistance of the film. Therefore, phosphating pretreatment is the basis of obtaining high quality phosphating film.

The purpose of surface adjustment is to promote the formation of fine phosphating film and improve the phosphating speed. There are two main types of surface conditioners, one is acidic surfactant, such as oxalic acid. The other is colloidal titanium. Both of them are widely used. The former has the function of removing light rust (water rust and wind rust formed in the process of workpiece operation). In the pretreatment process of phosphating, whether to choose the surface conditioning process and which surface conditioner to choose depends on the requirements of the process and phosphating film.

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