What is Water Stabilized Plasma Spraying? What are its characteristics compared with gas-stabilized plasma spraying?

       Water-stabilized plasma spraying is a high-power and high-speed plasma spraying method. It is a spraying method of plasma working gas of O2 and H2 formed by water vapor decomposition in an ion arc generated in a tunnel formed by high-speed rotating water. Compared with the gas plasma spraying method, the flame flow temperature is higher, the volume is larger and the volume is longer, especially the energy is higher, so it is especially suitable for the large-scale spraying of high melting point oxide ceramics. Its main advantages are as follows:



    1) Using water as the working medium, the operating cost is lower than that of gas-stabilized plasma spraying. To prepare the same ceramic coating, the total cost of water-stabilized plasma spraying is only 1/30~1/40 of that of gas-stabilized plasma spraying.

    2) The plasma jet has high temperature and wide high temperature area.

     ①Maximum temperature. The water-stabilized plasma arc is 30000K, and the gas-stabilized plasma arc is 15000K.

     ②The high temperature area is wide. The temperature of the water-stabilized plasma arc jet 20mm away from the nozzle outlet is 23500°C, and the temperature at 90mm away from the nozzle outlet is above 10000°C. The length of the flame is about 3 times that of the gas-stable plasma jet, and the high-temperature region in the diameter direction is correspondingly enlarged, and the volume of the high-temperature region is 10 times larger than that of the gas-stable plasma jet.

    3) High output power. The power of water-stabilized plasma arc can reach 160kW ~ 200kW, and the power of gas-stabilized plasma arc is generally 80kW (generally 50kW ~60kW).

    4) High production efficiency. Taking Al2O3 spraying as an example, the water-stabilized plasma spraying is 30kg/h~30kg/h, and the gas-stabilized plasma spraying is 2kg/h~5kg/h.

5) The coating quality is good.

6) The original ceramic coating can be prepared. Coating thickness can be greater than 2mm, up to 10mm.

7) Coarse-grained powder can be sprayed.

Water stable plasma spraying: 60μm~80μm, gas stable plasma spraying: <40μm.

However, the water-stabilized plasma also has shortcomings, mainly including: the water-stabilized plasma arc is oxidizing and is not suitable for spraying metal powder; the complete equipment system is huge, the spray gun has a complex and heavy structure (about 37kg), and the price is expensive.