Control of the Substrate Temperature during Plasma Spray Deposition

Thermocouple temperature measurements with the Al2O3 covered probe during vacuum plasma spray process were performed. The voltage of arc discharge during plasma spray was constant (31 V) and the arc discharge current varied from 420 A to 800 A. Temperature measurements were done for different distances between the probe and the nozzle of plasma gun (0.17 – 0.23 m). The gray body radiation model was used to describe the experimental results of temperature – time dependencies. The proposed model describes the kinetics of the sample heating in the plasma and the sample cooling after plasma spray had been turned off. The absorbtion factor of a probe surface was evaluated analyzing kinetics of the sample cooling