Plasma spraying of thermal spraying series

There are many methods for thermal spraying, among which flame spraying, arc spraying, plasma spraying (APS), explosive spraying are widely used. In recent years, supersonic spraying (HVOF) technology has also been developed. Plasma is a broad concept. In addition to the three forms of solid, liquid, and gas in nature, there is also the fourth state of matter - plasma. The plasma described in plasma spraying technology refers to the high-temperature plasma formed by the compressed arc of gas, also known as thermal plasma.

Atmospheric plasma spraying is a method of using argon, nitrogen, and hydrogen as ion gases to ionize and generate a plasma high-temperature jet, which melts or sprays the input material onto the working surface to form a coating. Mainly used for preparing metal ceramics, metal and ceramic coatings.

Controllable atmosphere plasma spraying involves placing the plasma spray gun in a sealed compartment and operating it by a robotic arm. Pumping the cabin to a vacuum state is called Vacuum Plasma Spraying (VPS). When the cabin is in a low-pressure state, it is called Low Pressure Vacuum Plasma Spraying (LPPS). The atmosphere of the cabin can also be an inert atmosphere or other protective atmosphere. This process expands the application of thermal spraying in the deposition of diamond films and superconductor oxide coatings.

The liquid stable plasma spraying method uses water, ethanol, and methanol as stable liquids in the spray gun, which generates oxidizing, neutral, or reducing plasma accordingly. Due to the high power of this spraying method, it is particularly suitable for spraying high melting point ceramic materials. The water stable plasma technology has been put into large-scale industrial production and has been widely applied in the United States, Japan, France, Germany, the Czech Republic, and Russia.

Reactive plasma spraying process is a unique coating method that utilizes the chemical process of plasma to manufacture composite materials, ceramics, intermetallic compounds, and other materials, such as TiAl and MoSi2-SiC. The research on this method has just begun and will soon be used for production.

In summary, the coating quality of plasma spraying not only depends on the quality of spraying equipment and materials, but more importantly, on the spraying process used. Reasonable selection of plasma spraying process is one of the important measures to ensure coating quality.