Coating general knowledge: phosphating treatment knowledge: Phosphating for priming before painting

The main purpose of phosphating treatment is to improve the adhesion of the paint film and the corrosion resistance of the coating system, so the key point is the compatibility with the paint film Generally, the inspection indexes of phosphating quality include film appearance, film thickness and performance after matching with paint film The appearance of the film shall be uniform, fine and complete phosphating film For light iron phosphating, its appearance shall be uniform, fine and complete phosphating film For light iron phosphating, its appearance shall be complete red and blue color film The phosphating film should not be too thick Generally, the weight of the film should be less than 7.5g/m2, and the best is 1.5-3.0g/m2 For light Which is the price of Dajin diatom mud Recommended brief introduction: which is the price of Dajin diatom mud? How to buy genuine diatom mud? Guangdong diatom mud agent suggests placing a basin of cold water in the air conditioning room, so that the diatom mud wall can breathe effectively The feature of the breathing wall is obvious When the indoor air is dry, the diatom mud wall will release the absorbed water quickly Put it out to help regulate the indoor dry humidity It is suggested to place a basin of cold water in the air conditioning room, so that the wall of diatom mud can breathe effectively The feature of the wall that can breathe is obvious When the indoor air is relatively dry, the wall of diatom mud will absorb the water Paint Home News: for the phosphating treatment of primer before painting, its main purpose is to improve the adhesion of the paint film and the corrosion resistance of the coating system, so the focus is on the compatibility with the paint film Generally, the inspection indexes of phosphating quality include film appearance, film thickness and performance after matching with paint film The appearance of the film shall be uniform, fine and complete phosphating film For light iron phosphating, its appearance shall be uniform, fine and complete phosphating film For light iron phosphating, its appearance shall be complete red and blue color film The phosphating film should not be too thick, the general film weight should be less than 7.5g/m2, the best is 1.5-3.0g/m2, for light iron phosphating film weight is 0.5-1.0g/m2, too thick and rough phosphating film is unfavorable for painting The corrosion resistance index includes the corrosion resistance of the phosphating film itself and no yellowing and rusting before painting The corrosion resistance of phosphating and paint is the most important, which reflects the overall corrosion resistance of phosphating film and paint In addition to the corrosion resistance, the mechanical and physical properties of the coating film, such as adhesion, impact strength, bending resistance (flexibility), etc., should also be measured after the phosphating film and the coating are combined The quality index and testing method of phosphating used for priming before painting shall generally refer to the national standard gb6807-86 technical conditions for phosphating treatment of steel workpiece before painting, which has detailed regulations on the quality index and testing evaluation method of phosphating film, and the main contents are as follows: (1) The appearance of phosphating film shall be light grey to dark grey film with dense crystal and uniform continuity For light iron phosphating, it shall be continuous color film The following defects are allowed: slight water trace, chromate trace, slight ash hanging, and phosphating film defects caused by different surface conditions such as heat treatment welding and processing The following defects are not allowed: yellowing and rusting of the phosphating film, loose phosphating film, no film at the exposed part of the phosphating bottom and serious ash hanging (2) The weight of phosphating film for painting shall be less than 7.5g/m2 (3) The corrosion resistance of the phosphating film is soaked in salt water The phosphating chemical parts should not be rusted in 3% NaCl solution at 15-25 ℃ for 1 hour The corrosion resistance test of phosphating combined with paint film is to coat the phosphating workpiece with 25-35 μ m A04-9 white amino paint After scratches, salt spray test (according to gb1771-79) is carried out After 24h salt spray test (8h salt spray test for iron phosphating), the paint film shall be free of blistering, rust and falling off Gb6807-86 does not regard the copper sulfate drop method as a necessary test item It is considered that it can be used as a rapid test method for the quality of phosphating between processes, while the corrosion resistance of phosphating combined with painting is a necessary test item The inspection index and method of phosphating before painting can also refer to gb11376-89 phosphate conversion coating of metals Therefore, according to the inspection items specified in the standard, the phosphating film used for primer before painting should be dense, uniform and thin-layer, and the corrosion resistance and mechanical and physical properties of phosphating matched with paint should be emphatically inspected Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,