A thermodynamical calculation shows that AlN powders were synthesized in the process by the overall reaction Al2O3(s)S+3C(s)+N-2(g)=2AlN(s)+3CO(g) and its minimum reaction temperature T-0=1852 K, if all reactants and ...A thermodynamical calculation shows that AlN powders were synthesized in the process by the overall reaction Al2O3(s)S+3C(s)+N-2(g)=2AlN(s)+3CO(g) and its minimum reaction temperature T-0=1852 K, if all reactants and products were in standard states. In the practical experiments, AlN phase appeared obviously at only 1300 degrees C, the major reasons are related to the partial pressure of its gaseous product p(co) and the mixed free energy. The synthesis temperature could be towered by either increasing N-2 flow rate or elevating N-2 pressure. On the other hand, as the temperature decreases, the equilibrium constant K-m also reduces, and the reducing rate strongly depends on the temperature: the lower the temperature, the higher the rate.展开更多
文摘A thermodynamical calculation shows that AlN powders were synthesized in the process by the overall reaction Al2O3(s)S+3C(s)+N-2(g)=2AlN(s)+3CO(g) and its minimum reaction temperature T-0=1852 K, if all reactants and products were in standard states. In the practical experiments, AlN phase appeared obviously at only 1300 degrees C, the major reasons are related to the partial pressure of its gaseous product p(co) and the mixed free energy. The synthesis temperature could be towered by either increasing N-2 flow rate or elevating N-2 pressure. On the other hand, as the temperature decreases, the equilibrium constant K-m also reduces, and the reducing rate strongly depends on the temperature: the lower the temperature, the higher the rate.
