Abstract: AlN ultrafine powders were synthesized at low temperature by Carbothermal Reduction Nitride (CRN) route from a sol-gel precursor by using aluminum nitrate, glucose and calcium nitrate as raw materials. The influence of Ca-compound on the phase transformation behavior of the precursors, as well as the particle size and morphology of synthesized AlN powders, were investigated. X-ray diffraction patterns showed that Ca-compound reacted with alumina powder and resulted in aluminate phase of CaAl4O7, Ca3Al10O18, CaAl2O4 and Ca12Al14O33. Those aluminate phases formed liquid during the nitradation process, which promoted the transformation of Al2O3 to AlN and vaporized at high temperature. Compared to the approach without additive, the use of Ca-compound addition reduced the synthesis temperature of AlN from 1500 ℃ to 1400 ℃. SEM photographs showed that AlN powders synthesized with Ca-compound addition were larger than those without Ca addition, and high doping of Ca-compound lead to the growth of AlN powders. With [Ca]/[Al] of 0.0262, the particle sizes of AlN powders synthesized at 1350 ℃ were 60-80 nm. When the nitradation temperature was increased to 1400 ℃, the single AlN with the particle sizes of 100-180 nm was obtained.

Key words: AlN, ultrafine powder, Cacompound, solgel, low temperature synthesis

摘要： 以硝酸铝、葡萄糖和硝酸钙为原料，通过溶胶-凝胶工艺获得了组分均匀的Al2O3、C和CaO前驱体，进而利用碳热还原反应合成超细氮化铝粉体，探讨了钙助剂对氮化铝合成温度及粉体颗粒生长的影响规律。结果表明：钙助剂的添加，通过与前驱体中氧化铝在较低温度下发生反应，先后生成CaAl4O7、Ca3Al10O18、CaAl2O4和Ca12Al14O33等铝酸钙相；上述铝酸钙相能在较低温度下形成液相，可有效促进氮化铝的合成和粉体颗粒的生长，从而在1400 ℃合成纯相氮化铝。当原料中钙铝摩尔比为0.0262时，在1350 ℃氮化得到了粒径60-80 nm的氮化铝粉体，仅有少量铝酸钙相存在；当氮化温度上升至1400 ℃时，铝酸钙相因挥发而消失，得到粒径100-180 nm的单相氮化铝粉体。

关键词: 氮化铝, 超细粉体, 钙助剂, 溶胶凝胶, 低温合成