Thermal plasma spheroidization of aluminum oxide and characterization of the spheroidized alumina powder

Spheroidization of aluminum oxide powder was done by thermal plasma processing. The powder was injected into the plasma jet issuing out of a DC plasma torch. Trajectories of the particles in the plasma jet were seen using a high speed camera and then in-flight velocity and temperature of alumina particles were determined using a ‘Spray Watch’ system. Characterization of the spheroidized powder was done by Scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The results showed that increase of the plasma torch power leads to increase in the extent of spheroidization and conversion to γ-alumina. Results obtained showed that the process can be extended to synthesize free flowing alumina powder for thermal spray applications.