Synthesis of aluminum nitride ultrafine powder via carbon thermal reduction nitridation process based on non-hydrolytic sol-gel method

The alumina xerogel was prepared by non-hydrolytic sol-gel method using anhydrous aluminium trichloride with isopropyl ether as raw materials. After the xerogel was calcined at 800°C, the phase of γ-Al2O3 began to crystallize from the amorphous phase, and then converted to α-Al2O3 near 1200°C. The smaple kept a high specific surface area of 145 m2/g to about 900°C, and possessed the mesoporous structure. Using the alumina xerogel as the aluminum source, aluminum nitride ultrafine powder was synthesized by the carbon thermal reduction nitridation process. The resluts showed that when the alumina xerogel was pre-calcinated at 300°C, the C/Al molar ratio amount of the carbon was 7.8, the flow rate of nitrogen was 80 mL/min, the synthesis temperture was 1450°C and the soaking time was 2 h, the high purity hexagonal phase aluminum nitride powder with the average size of about 400 nm could be obtained.