水合氧化铝的热处理及纳米氧化铝的颗粒特性

The Heat Treatment Process of Hydrous Alumina and Caracteristics of Nanometer Al_2O_3

利用IR、XRD、TG-DTA和TEM等测试技术研究了醇铝的水解产物——水合氧化铝的特性及水合氧化铝的热处理过程,探讨了热处理工艺对纳米氧化铝颗粒特性的影响规律。结果表明,醇铝的水解产物水合氧化铝为富含吸附水和结构水的非晶态一水铝石,300℃煅烧后出现部分非晶态γ-Al2O3;煅烧温度、保温时间和冷却方式均能影响纳米氧化铝粒子的晶型、大小和形貌,其中煅烧温度影响最大,冷却方式影响次之,保温时间影响最弱;在750℃/3h、800℃/4h、900℃/4h、950℃/4h和1000℃/4h随炉冷却工艺条件下,分别得到粒径为3￣5nm、3￣5nm、5￣10nm、10￣15nm和50￣100nm的纤维状或球状、α相或γ相的纳米氧化铝粒子。

By means of IR, XRD, TG-DTA and TEM, the characteristics and the thermal treatment processes of hydrous alumina as the hydrolysate of aluminium alkoxide were examined, and the influence of various thermal treatment processes on the granular characteristics of nano-Al2O3 particles was also investigated. The results showed that hydrous alumina was amorphous diaspore [AlO（OH）] retaining abundant adsorptive and structural crystal water. Parts of AIO（OH） were converted into amorphous T-Al2O3 after calcination at 300 ℃. Calcination temperature, holding time and cooling mode exerted effects on the crystal shape, size and morphology of the alumina particles. The influence of the calcination temperature is the most significant, followed by cooling mode. In contrast, the influence of holding time was the lowest. Spheric or fibrillar α- or γ-Al2O3 with the size of 3-5 nm, 3-5 nm, 5-10 nm, 10-15 nm and 50-100 nm might be produced under the thermal treatment conditions of 750 ℃ for 3 h, 800 ℃ for 4 h, 900 ℃ for 4 h, 950 ℃ for 4 h and 1 000 ℃ for 4 h, respectively.