What are the advantages and functions of plasma spraying technology

       

Plasma spraying technology is a relatively new thermal spraying technology. The principle of plasma spraying technology is to change the surface properties of materials. The material is heated to a certain molten or semi-melted state. They are blown into tiny particles. The coating processing method of spraying on the surface of the substrate with island velocity air flow to form various coatings, the size of which is the same as other spraying methods, has the advantages of unlimited part size, wide substrate, and small processing edge. The surface of commonly used substrate parts is sprayed strengthening, etc.

1. The substrate is heated less, the parts are not deformed, and the heat treatment state remains unchanged. Since the parts are not charged during the spraying process and the base metal is not melted, although the temperature of the plasma flame is high, the energy is very concentrated, and the axial temperature gradient of the plasma arc is large. The precision of some thin-walled parts generally does not exceed 200 °C, which is very beneficial to the modification accuracy of the parts. Since the heat treatment properties of the base metal will not change below 200°C, some high-strength steels can be sprayed.



2. The process is stable and the coating quality is high. The plasma spraying process parameters can be quantitatively controlled, the process is stable, and the coating reproducibility is good. During plasma spraying, the velocity of molten particles can reach 180-480m/s or even higher, which is much higher than 45-120m/s during oxyacetylene flame powder spraying. When the molten particles collide with the parts, the deformation is sufficient, the coating is dense, and the bonding strength is high. The normal bonding strength of plasma spray coating and base metal is generally 30-70mpa, while the normal bonding strength of oxyacetylene flame spraying is 5-20mpa. Since the atmosphere can be controlled by changing the gas during plasma spraying, the oxygen or nitrogen content in the coating can be greatly reduced.



3. There are various types of spraying materials and various types of coatings. Due to the high temperature of the plasma flame, various spray materials can be heated to a molten state. Therefore, plasma spraying can use a variety of materials, and can obtain spray coatings with various properties, such as wear-resistant coatings, thermal insulation coatings, high-temperature anti-oxidation coatings, insulating coatings, etc.; in terms of the versatility of coatings , Oxyacetylene flame spraying, arc spraying and other spraying, high frequency induction spraying and explosive spraying are not as good as plasma spraying.