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Abstract: Effect of He addition to Ar as the discharge gas on the substrate surface temperature during thermal plasma jet (TPJ) annealing is investigated. The maximum surface temperature (T max) increases from 1370 to 1470 K with increasing He fraction (R He) from 0 to 28%, then decreases to 1040 K with increasing R He to 86%. It has been confirmed that the TPJ is efficiently concentrated when He addition is around 30%, which suggests that the increase in T max is due to the increase in the power density induced by thermal pinch effect. By adding 30% He and increasing the total gas flow rate to 15.4 L/min, T max is increased to 1580 K. [Copyright &y& Elsevier]

Abstract: Temporal variations of substrate surface temperature in scanning Ar thermal plasma jet has been investigated based on an analysis of transient changes in optical reflectivity. The accuracy of the temperature measurement has been evaluated to be 30 K at temperature around 1760 K. The maximum surface temperature (T max) is controlled in the range from ∼960 to ∼1780 K with keeping the annealing duration (t a) around ∼3 ms by changing the Ar gas flow rate (f) and distance between the plasma jet and the substrate (d) under a constant scanning speed (ν) of 500 mm/s. [Copyright &y& Elsevier]