LTE and non-LTE gas temperatures in loaded and unloaded plasmas during spraying of NiAl powders.

摘要

The purpose of this research is to contribute to the science of the complex particle plasma interaction in the plasma spray process. The relationship between the chaotic torch, the nonequilibrium plasma, the accelerating vaporizing particle, and the particle substrate interaction must be understood to relate coating characteristics to process parameters. This will lead to improved models, scalability, and appropriate monitoring and control of the process. This work focuses on the nonequilibrium plasma plume through which the particles must pass. Present models are based on the best knowledge available, but do not predict particle size, velocity, and surface temperatures that are consistent with experiments. Plasmas at pressures at and below atmospheric have been shown to deviate from local thermodynamic equilibrium (LTE). 15 refs., 5 figs.