Excitation temperature of smart spraying plasmas produced from modulated arc discharge

Plasma spraying preparation of ceramic coatings is strongly affected by the plasma parameters such as excitation temperature. Plasma parameters are the most important subjects for good coating production. In this paper, the excitation temperature of smart spraying plasmas produced from modulated arc discharge was compared with that of conventional steady DC arc spraying plasmas. Two different DC power sources, one of which is a stabilized-current DC arc power supply, the other is also a DC power source that supplies output current with 360 Hz amplitude modulation, were used to sustain the arc discharge plasma spraying system. Although the I-V characteristics of the two kind discharges were similar to each other, the temperature of the modulated discharge was slightly higher than that of the stabilized discharge. The higher temperature was thought to be due to the modulated discharge power. A high-speed CCD camera was used to evaluate the plasma modulation and fluctuation.