Aluminum nitride (AlN) was synthesized by carbothermal reduction and nitridation method from a mixture of various transition alumina powders and carbon black using 2.45 GHz microwave irradiation in N2 atmosphere. We achieved the synthesis of AlN at 1300–1400°C using 2.45 GHz microwave irradiation for 60 min. Our results suggest that θ‐Al2O3 is more easily nitrided than γ‐, δ‐, and α‐Al2O3. On the other hand, nitridation ratio of samples synthesized in a conventional furnace under nitrogen atmosphere were zero or very low. These results show that 2.45 GHz microwave irradiation enhanced the reduction and nitridation reaction of alumina.

Aluminum nitride (AlN) was synthesized at 1000‐1400°C from a mixture of alumina and carbon powders using 2.45 GHz microwaves in a N2 atmosphere. High nitridation ratios (>0.90) were obtained in the temperature range 1200‐1400°C. The apparent activation energy of the carbothermal reduction and nitridation (CRN) reaction using 2.45 GHz microwave irradiation was calculated from the nitridation ratio. The value obtained, 79.9 kJ/mol, is 11% of the energy reported for conventional synthesis using α‐Al2O3 as the raw material. This result indicates that 2.45 GHz microwave irradiation could promote the kinetics of the CRN reaction, and AlN could be effectively synthesized at low temperature.