Abstract
In-flight measurement of the surface temperature of plasma-sprayed particles is important for the correlation of particle characteristics to coating structure and properties. However, the use of optical pyrometry for particle surface temperature measurement has inherent uncertainties due to nonthermal emission signals in the plasma/particle plume. This nonthermal signal is especially bothersome near the torch exit and in regions of the plume where there are few particles. This work presents measurements of the nonthermal signals present when making temperature measurements of plasma-sprayed molybdenum particles. Changes in the nonthermal emission signals were found to be caused by particle vapor, the spectral plasma loading effect, and particle reflection of plasma light. Care must be taken to avoid particle temperature errors due to these effects.
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Hollis, K., Neiser, R. Analysis of the nonthermal emission signal present in a molybdenum particle-laden plasma-spray plume. J Therm Spray Tech 7, 383–391 (1998). https://doi.org/10.1361/105996398770350864
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DOI: https://doi.org/10.1361/105996398770350864