The in-flight particle parameters of velocity, size, and temperature were measured for nickel powder injected into an Ar/H2 DC plasma jet, by using the Light Pulse Analysis method, which has been recently developed and verified in the induction plasma mode. Measurements were carried out under several plasma power levels from 18 to 32kW, as well as at different axial positions of 75 to 125mm from the nozzle exit of plasma torch. Although the particle velocity shows almost constant value of 100-120m/s through axial distance, the particle surface temperature has a maximum value at around Z=125mm under the plasma power condition of 21 to 24kW. The heating property of nickel paricle with a low melting point 1, 728K is found to be affected significantly by the plasma power, as expected. The cross-correlation between the particle parameters and hardness of coating was investigated. The results showed that the abrasion weight of the coating formed at the lower power of 21kW is small compared to that formed at high power condition of 32kW. Thus, for the nickel powders with relatively lower melting point, an excessive plasma power is not necessary for forming the appropriate spray coating.
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