Phosphating, passivation and spraying of metal surface treatment

Metal surface treatment - phosphating, passivation, spraying and other chemical processes are used to treat the metal surface in order to achieve coloring, rust prevention and other desired application effects

phosphating

Phosphorization is a process of chemical and electrochemical reaction to form phosphate chemical conversion film, which is called phosphating film. The purpose of phosphating is to provide protection for the base metal and prevent the metal from being corroded to a certain extent. Used as a primer before painting to improve the adhesion and corrosion resistance of the paint film; It can be used for friction reduction and lubrication in metal cold working process.

passivation

Metal or alloy affected by a number of factors, the phenomenon of chemical stability significantly enhanced, known as passivation. The phenomenon of metal passivation caused by some passivating agents (chemicals) is called chemical passivation. Such as concentrated HNO3, concentrated H2SO4, HClO3, K2Cr2O7, KMnO4 and other oxidants can make the metal passivation. After the metal is passivated, its electrode potential moves in the positive direction, making it lose its original characteristics, such as the passivated iron in the copper salt can not be changed out of the copper. In addition, electrochemical methods can also make the metal passivated, such as the Fe in H2SO4 solution as an anode, with an applied current to make the anode polarized, using a certain instrument to increase the iron potential to a certain extent, Fe passivated. Metal passivation caused by anode polarization is called anode passivation or electrochemical passivation.

The mechanism of passivation can be explained by the theory of thin film, that is, the passivation is due to the interaction of metal and oxidation properties, which generates a very thin, dense, good covering performance and firmly adsorbed passivation film on the metal surface. This film exists as a separate phase, usually metal oxide compounds. It plays the role of separating the metal from the corrosive medium completely, preventing the metal from contacting with the corrosive medium, so that the metal basically stops dissolving and forms a blunt state to achieve the role of corrosion prevention.

Advantages of passivation

1. Compared with the traditional physical sealing method, the passivation treatment has the characteristics of absolutely not increasing the thickness of the workpiece and changing the color, improving the precision and added value of the product, making the operation more convenient;

2, because the passivation process belongs to the state of no reaction, passivation agent can be repeatedly added to use, so the life is longer, the cost is more economical.

3, passivation promotes the formation of oxygen molecular structure passivation film on the metal surface, the film layer is dense, stable performance, and has a self-repair effect in the air at the same time, so compared with the traditional method of coating anti-rust oil, the passivation film formed by passivation is more stable, more corrosion resistance.

spraying

Pressure or electrostatic force will be used to attach paint or powder to the surface of the workpiece, so that the workpiece has anti-corrosion and decorative appearance.

injection

Spray paint on the surface of the product and dry it naturally.

The lacquer that bake

On the base material on primer, finish, every time the paint, are sent to the dust-free baking room, baking.

impregnation

It is a kind of microporous (fine seam) infiltration sealing process. The sealing medium (usually low viscosity liquid) through natural penetration (that is, micro hole self-priming), vacuum and pressure methods into the micro hole (slit), the gap is filled, and then through natural (room temperature), cooling or heating methods will be sealed in the gap of the sealing medium curing, to seal the gap.