How to solve the problem of particle splashing during plasma spraying?

The problem of particle splashing during plasma spraying is a common challenge, which may affect the uniformity, adhesion, and overall quality of the coating. Here are some suggestions to help solve this problem:

At first, optimizing spray parameters was the key to solving the problem of spray particle splashing. Electric power is an important factor affecting the spraying effect. Insufficient electrical power may lead to insufficient melting of powder particles, resulting in a decrease in deposition rate due to excessive elasticity when in contact with the substrate; Excessive electrical power can lead to severe oxidation and erosion of powder particles, accompanied by a large amount of splashing of liquid-phase particles. Therefore, it is necessary to adjust the electrical power to an appropriate range based on the characteristics of the powder material and matrix to ensure that the powder particles are fully melted and deposited smoothly.

Secondly, the selection and control of the main gas for plasma spraying also have a significant impact on the spraying effect. Usually, the main gas is Ar gas, and its flow rate directly affects the state of the plasma flame and the melting of powder particles. Excessive airflow may cause the plasma flame to carry away more powder particles, resulting in insufficient heat to melt all particles; However, a low gas flow rate may prevent the plasma arc from reaching the desired temperature, affecting the melting of particles. Therefore, it is necessary to finely adjust the gas flow rate to balance the strength of the plasma flame and the melting requirements of the powder particles.

In addition, the spraying distance is also a factor that needs to be carefully considered. Excessive spraying distance may cause a decrease in the velocity and temperature of particles when they reach the surface of the substrate, while insufficient distance may result in insufficient melting of particles in a short period of time, while being strongly affected by the plasma flame. Therefore, it is necessary to find a suitable spraying distance to ensure that the particles have appropriate velocity and temperature when reaching the substrate, thereby achieving high-quality coating deposition.

In addition to adjusting the above parameters, the movement speed of the spray gun is also a factor that affects the spraying effect. Although the movement speed of the spray gun has a relatively small impact on the spraying process compared to other parameters, a too fast movement speed may result in uneven coating, while a too slow movement speed may increase spraying time and cost. Therefore, it is necessary to choose an appropriate spray gun movement speed based on the actual situation.

In addition, regular maintenance and inspection of spraying equipment are also important measures to solve the problem of spray particle splashing. Equipment aging or wear may lead to unstable spraying and increase the risk of particle splashing. Therefore, it is necessary to regularly maintain and inspect the equipment to ensure that it is in good working condition.

In summary, solving the problem of particle splashing during plasma spraying requires multiple approaches, including optimizing spraying parameters, selecting appropriate spraying gases and flow rates, adjusting spraying distance, controlling spray gun movement speed, and regularly maintaining spraying equipment. By comprehensively applying these measures, the problem of spray particle splashing can be effectively reduced, and the uniformity, adhesion, and overall quality of the coating can be improved.

Please note that the above suggestions are based on general experience and may need to be adjusted and optimized according to specific powder materials, matrix materials, and coating requirements in practical applications. Therefore, in practical operation, it is recommended to conduct sufficient experiments and verification to find suitable spraying process parameters and conditions.