Why do surface conditioner need to be used for treatment before phosphating?

By using surface conditioner to adjust the metal surface, the unevenness of the surface state caused by alkaline degreasing or acid pickling rust removal can be eliminated, which make it form a large number of extremely fine crystal centers on the surface of metal,  thereby accelerate the phosphating reaction rate and facilitate the formation of the phosphating film. Surface adjustment is particularly important for  zinc phosphate solutions.

Nowadays, cathodic electrophoretic primers with excellent corrosion resistance are widely used in automotive coatings. Therefore, it is required that the resistance of the phosphating film be small and uniform in all parts. During the electrophoretic process, the phosphating film has good acid and alkali resistance and is not easily soluble. This means that low zinc phosphating with thin layer, fine, uniform, dense, and good acid resistance is required. Therefore, for high-quality automotive coatings, surface adjustment before phosphating has become an indispensable process.

Now, a more effective Colloidal titanium salt surface conditioner is used for phosphating treatment. Due to the high surface energy of the colloid particles, they have a strong adsorption effect on the surface of the object. The colloid particles adsorb on the surface of the workpiece to form a uniform adsorption layer. During phosphating, this extremely thin adsorption layer is a layer of evenly distributed and numerous phosphate crystal nuclei, which promotes the uniform and rapid formation of crystals, limits the growth of large crystals, and promotes the refinement and density of the phosphating film, improves film-forming properties, shortens phosphating time, reduces film thickness, and also eliminates the influence of differences in surface state of steel on the quality of phosphating.