ã€China Aluminum Network】 The surface treatment of the workpiece prior to painting is an important part of the electrophoretic coating. It mainly involves processes such as oil removal, rust removal, surface adjustment, phosphating, and passivation. The treatment is good or bad, not only affects the appearance of the membrane, reduces the corrosion resistance, but also can destroy the stability of the paint. Therefore, for the surface of the workpiece before painting, it is required that there be no oil stains, rust marks, no pre-treatment chemicals, phosphating precipitates, etc., and the phosphating film crystallizes densely and uniformly.
For the pre-processing of various processes, will not be discussed, only to pay attention to some points:
(1) If the removal of oil rust is not clean, it will not only hinder the formation of the phosphating film, but also affect the coating adhesion, decorative properties and corrosion resistance. The film is prone to shrink holes, pinholes, "flower face" and other ills.
(2) Phosphorization: The purpose is to improve the adhesion and corrosion resistance of the electrophoretic membrane. Its role is as follows:
A. Due to physical and chemical effects, the adhesion of the organic coating to the substrate is enhanced.
B. Phosphating film makes the metal surface from a good conductor to a bad conductor, thereby inhibiting the formation of microbatteries on the metal surface, effectively impeding the corrosion of the coating, and multiplying the corrosion resistance and water resistance of the coating.
In addition, a satisfactory phosphating film can only be formed on a clean, uniform, grease-free surface on the basis of thorough degreasing. In this respect, the phosphate film itself is a more intuitive and reliable self-test for the effect of the pretreatment process.
(3) Passivation: It refers to the protective film layer formed by the pigment in the coating on the metal surface, such as chromate rust-proof pigment.
(4) Washing: The pre-treatment of each stage of washing will have a great impact on the quality of the entire pre-treatment and paint film. A deionized water rinse is required before painting to ensure that the dripping conductivity of the coated object is not greater than 30 μs/cm. Cleaning is not clean, such as the workpiece: A. Residual residual acid, phosphating liquid, the resin in the paint liquid flocculation, stability deterioration; B. Residual foreign matter (oil, dust), film shrinkage, particles and other ills; C. Residual electrolytes, salts, resulting in increased electrolysis reactions, pinholes and other ills.
Bathroom Floor Drain,Bathroom Long Stainless Steel Floor Drain,Stainless Steel Black Floor Drain,Stainless Steel Bathroom Floor Drain
Kaiping City Jinqiang Hardware Products Co.,Ltd , https://www.kimpowerdrain.com