Tow-Step Synthesis of Aluminum Oxynitride (AlON) via Carbothermal and Nitridation Route

The aim of this research was to study synthesize gamma aluminum oxynitride powder with cubic spinel structure. In order to carry out this process, carbothermal reduction and nitridation of α-alumina as starting powder was used. This process was carried out in two steps, that in the first step at 1550˚C, a portion of α-alumina was reacted with carbon and aluminum nitride (AlN) was formed, then in the second step at 1750°C, the residual alumina reacted with aluminum nitride, and aluminum oxynitride was formed. In order to achieve the dominant phase of aluminum oxynitride, different amounts of carbon (5, 10, 15 and 20 wt%) were used and the weight percentages of the middle phases at 1550°C, 1600°C and 1650°C were investigated for optimal sample. The results indicate that the highest percentage of aluminum oxynitride is present in 10 wt% of carbon.