Sol-gel工艺制备氧化铝超微细粉及其机理的研究

Studies on the Mechanism and the Preparation of Ultrafine Powder Al_2O_3 by Sol-gel Processing

本文采用Sol-gel工艺制备了不同晶型的氧化铝超微细粉,γ—Al_2O_3、θ—Al_2O_3粒度可达100～200A,呈针状,α—Al_2O_3的平均粒度为500A左右,呈卵圆形。并用FT—IR、XRD、DTA/TG和TEM等手段研究了氧化铝凝胶在煅烧过程中的物相和显微结构的变化。发现氧化铝凝胶在低于300℃时干燥是稳定的,其物相变化过程为γ—AlO(OH)、β—Al(OH)_3(少量)→γ—AlO(OH)(100℃)→γ—Al_2O_3(400℃)→θ—Al_2O_3(1000℃)→α—Al_2O_3(1200℃)。

In this paper, different kinds of phase alumina ultrafine powder were prepared by Sol-gel processing. For example, particle size of γ-Al_2O_3 and θ-Al_2O_3 is needle particle of about 100～200A, Particle size of α-Al_2O_3 is spherical particle of about 500A. Phase and microstructure changes of alumina gels in sintering were studied with FT-IR, XRD, DTA/TG and TEMetc. It has been discovered that the solid structure of the dried gel is stable up to at least 300℃,and phase transformation within the solid is bayerite→boehmite→γ- alumina (400℃)→θ-alumina(1000℃)→α-alumina (1200℃).