3.carefully choose pigments and fillers
Anti-rust pigments and fillers are divided into physical anti-rust and chemical anti-rust. The formula adds physical anti-rust pigments and fillers, mica iron oxide and superfine mica powder. The addition of these flaky structure materials can increase the density of the paint film and reduce the corrosion. The permeability of the medium plays a shielding role for the corrosive medium. Chemical anti-rust pigments mainly include lead pigments and chromate and phosphate pigments. Due to environmental protection requirements, the first two are generally not used. The old formula uses zinc phosphate and aluminum tripolyphosphate, and the new formula uses a new type of composite zinc aluminum phosphate as the main anti-rust pigment, supplemented by a certain amount of zinc phosphate and aluminum tripolyphosphate, whose content is about About 25% is appropriate. Phosphate generated by phosphate dissociation can passivate the metal surface and cause anodic polarization, while zinc ions and aluminum ions react at the cathode to generate insoluble substances and cause cathodic polarization, which can greatly improve the coating film. The anti-rust ability.
4.choose the right adhesion promoter
To improve the adhesion of the coating film in dry and wet states, it is necessary to select a suitable resin curing system. Coupling agents can increase the adhesion of organic materials to inorganic substrates. After the adhesion between the coating film and the substrate is increased, it can greatly improve the anti-foaming ability of the coating film, because the foaming is the partial loss of the adhesion of the coating film. It is formed by peeling off the surface of the substrate.
5.Film thickness
The salt spray resistance is also related to the thickness of the coating film. It takes a long time for the water and oxygen molecules of the coating film to penetrate the coating, and the salt spray resistance is directly proportional to the thickness of the coating film. The salt spray resistance of coatings is a very important indicator. It should be considered from many aspects to choose a suitable coating formulation to improve the salt spray resistance while ensuring that the cost of the coating does not increase or increase little.