Abstract
The feasibility of fabrication aluminum nitride coating through plasma nitriding of Al2O3 powder in N2/H2 plasma was investigated. Cubic-AlN (c-AlN)/Al2O3 composite coating was fabricated and it contains c-AlN, alpha- Al2O3, Al5O6N and gama- Al2O3. The particles melted, spheroidized and reacted in the plasma and formed aluminum oxynitride (AlON). The particles collide, flatten, and the AlON is easily nitride to c-AlN(same cubic symmetry). The c-AlN was formed by rapid solidification of AlON and plasma irradiation on the substrate. The high quenching rate of the plasma flame prevents AlN crystal growth to form the hexagonal phase. The in-flight reaction enhanced the AlN content.
