What are the common plasma spraying faults and their solutions?

Plasma spraying is a commonly used surface spraying technique, widely used in fields such as aerospace, automotive manufacturing, electronics, machine tools, and metallurgy. However, due to various factors such as materials, processes, and equipment, some malfunctions may occur during the plasma spraying process. This article will introduce common plasma spraying faults and their solutions.

1. Arcing Lake

Yanhu refers to the arc phenomenon that occurs during the plasma spraying process. Electric arcs can lead to a decrease in spray quality and even cause equipment damage. The main reasons for Yanhu Lake are: excessive electrode spacing, electrode damage, unstable gas flow rate, etc. The solutions include reducing electrode spacing, replacing damaged electrodes, adjusting gas flow rate, etc.

2. Uneven spray coating structure

Uneven spray coating structure may lead to issues such as high surface roughness and uneven thickness. The reasons for this problem include uneven gas flow during spraying, nozzle blockage, and inappropriate spraying distance. The solutions include adjusting the spray gas flow rate, cleaning clogged nozzles, and controlling the spray distance.

3. Spray powder does not adhere

The non adhesion of spray powder may be due to inadequate surface treatment before spraying, or improper settings of spray gun and gas process parameters. The solution is to perform surface treatment such as sandblasting, acid washing, etc., while adjusting the spray gun and gas parameters.

4. Blockage of spray gun

Blockage of the spray gun can lead to unstable gas flow and reduced spraying effect. The main reasons for gun blockage are: high powder humidity, large powder particles, and colloidal particle blockage. The solutions include controlling the humidity of the powder, sieving fine powders, and removing colloidal particles.

5. Poor adhesion

Poor adhesion can cause the sprayed layer to easily peel off, affecting the quality of spraying. The reasons for poor adhesion include: low spraying temperature, improper surface treatment, poor powder quality, etc. The solution is to increase the spraying temperature, perform appropriate surface treatment, and use high-quality powder.

6. Pores

Pores refer to small holes in the spray coating, which can affect the sealing and corrosion resistance of the spray coating. The main reasons for porosity are impurities on the sprayed surface and excessive powder particles. The solution includes: performing appropriate cleaning treatment, screening fine powders, etc.

7. Cracks appear in the spray coating

Cracks in the spray coating may be caused by temperature changes during the spraying process. The solutions include controlling temperature changes during the spraying process, optimizing spraying parameters, etc.

8. Uneven color of spray coating

Uneven color of the spray coating may be caused by uneven distribution of powder color and other reasons. The solutions include: controlling the color distribution of the powder, increasing the thickness of the spray coating, etc.

9. Spray speed too fast

Excessive spraying speed may lead to a decrease in the quality of the sprayed layer. The solution is to improve the spraying quality by adjusting the spraying speed.

10. Explosion occurred during the spraying process

The explosion during the spraying process may occur due to improper control of powder and oxygen. The solutions include adjusting the gas ratio and improving the safety of the spraying equipment.

In summary, common faults in plasma spraying include uneven coating, lack of powder adhesion, nozzle blockage, poor adhesion, porosity, cracks, uneven color, rapid spraying speed, and explosion. By adjusting the spraying parameters reasonably, optimizing the spraying process, and using high-quality materials, these faults can be effectively solved, and the quality and efficiency of plasma spraying can be improved.