Fabrication of AIN/AI_2O_3 coatings via atmospheric reactive plasma nitriding of Al_2O_3 powders

摘要

Plasma sprayed alumina (Al_2O_3) coatings has showed a great effect in service the life of engineering tools, while its low thermal conductivity limits its application in heat exchange applications. Aluminum nitride (AIN) is a promising material to improve the thermal conductivity of Al_2O_3 coatings. This paper proposed a new way to fabricate AIN/Al_2O_3 coatings through reactive plasma nitriding of Al_2O_3 powders. It was possible to fabricate cubic-AlN/Al_2O_3 coatings by spraying Al_2O_3 powders in atmospheric plasma spray process (APS). During plasma Al_2O_3 powder reacted in high temperature N_2/H_2 plasma to form aluminum oxynitride and it easily nitride to produce the cubic AIN phase.