Efficiency of particle acceleration,heating, and melting in high-enthalpy plasma jets

Local and average values across the cross section of a plasma jet of the velocity and temperature of Al₂O₃, Ti, and Mo particles heated by plasma are determined as a result of data processing on high-speed registration of particle tracks; the velocity changes of these particles along the axis of a plasma jet at different modes of operation of the experimental setup of plasma spraying are also determined. These data made it possible to choose the optimal spraying mode, wherein the particles collide with the surface of the substrate in a molten state, where the fields of velocities and temperature are homogeneous. Calculation of all the parameters of particles mentioned is carried out with regard to their dynamic and thermal delay relative to carrying flow, nonisothermality of particles of low-heat-conducting oxides, as well as matter evaporation from the particles’ surfaces. Calculation results are in satisfactory agreement with the experimental data.