Plasma spraying is a mature coating process that has received widespread attention due to its deposition structure performance.

The plasma gas generated by an arc is composed of free electrons, ionized atoms, some neutral atoms, and undissociated diatomic molecules. The temperature of the plasma jet core may exceed 30000K. Through convergent divergent nozzle, the gas velocity in the plasma spray can change from subsonic to supersonic. The heat transfer in the plasma jet of diatomic gas on the surface of powder is mainly due to the recombination of ions and atoms and the absorption of radiation. With the advantages of plasma column atmosphere, plasma spray can be used for surface modification and treatment,

In the process of plasma spraying, the material (raw material) to be deposited is usually powder, sometimes liquid, suspension or wire. The plasma jet generated by the plasma spray gun is introduced, and the melted droplets flatten there, rapidly solidify and form deposits. Generally, sediment adheres to the substrate as a coating. It has been widely used in various industrial fields such as metal alloys, carbides, mixtures, metal ceramic abrasives, and oxide ceramics for wear and corrosion protection, insulation, repair, and restoration materials.

High temperature plasma spraying makes it particularly suitable for spraying refractory metal and ceramic coatings. Plasma spraying is an advanced technology that can produce high-density, oxide free, and very pure high-end coatings.

What are the advantages of plasma spraying?

1. The main advantage of this process is its high deposition rate, which is suitable for various metal and oxide coatings.

2. The advantages of plasma spraying: There are various types of coating materials that can meet various needs, and almost all materials are provided in appropriate powder form. High quality coatings, such as flame spraying or arc spraying, can be applied to various substrate materials including metals, ceramics, plastics, glass, and composite materials using plasma spraying coatings.

3. Efficient spraying: Plasma spraying uses instantaneous high-temperature plasma reaction for spraying, resulting in high total energy input speed and power density, and significant improvement in spraying efficiency.

4. High temperature working environment: The working temperature can reach thousands of degrees, and spraying can be carried out in high temperature environments, resulting in better coating quality at high temperatures.

5. High energy density: Plasma spraying technology provides a high energy density during the spraying process, ensuring the molten state of the spray and maintaining the high density of the coating.

6. Good treatment effect: This technology does not require the use of solvents or other chemicals for surface cleaning during surface treatment, and there is no damage or erosion, resulting in a good treatment effect.

What are the drawbacks of plasma spraying?

High cost: Plasma spraying technology has a high cost, unstable spraying effect, and low spraying efficiency, requiring long-term operation and consuming more energy.

Low spraying efficiency: Plasma spraying technology cannot perform large-scale coating spraying and requires a certain level of technical expertise to operate, which limits the spraying efficiency.

Material loss: In plasma spraying technology, the material utilization rate is low, and spraying processing also generates emissions.

Usually, the purchase and use of air plasma spraying equipment are very expensive. Similar to all other thermal spraying processes, it is a linear spraying process, making it difficult to cover inner holes with smaller diameters or limited contact surfaces. Plasma jet guns will experience rapid deterioration of internal gun electrodes and other internal components, resulting in frequent replacement of gun electrodes and requiring quality control to maintain coating consistency. Plasma equipment is not suitable for manual operation and requires the use of automatic firearm operators.