The Preparation Of Nano Alumina And Alumina Hollow Spheres

α-Al₂O₃ is a stable phase in thermodynamic and kinetics, the phase transformation temperature of α-Al₂O₃ is so high, which promotes the agglomeration; The uncontrollable and uneven shell thickness are the shortcoming in the preparation of the hollow sphere materials with nanometer-scale shell thickness. In this paper, we focus on exploring the methods for preparing the nano alumina and alumina hollow spheres, the main contents include the following three parts.Firstly, the nano Al₂O₃ powder was prepared by alkoxide hydrolysis via using the α-Al₂O₃ as a seed, adding the glucose and polyvinlptyrrolidone as surfactants. We have explored the effects of seed, glucose and polyvinlptyrrolidone, in this experiment, the γ-Al₂O₃ powder can be obtained after calcining at 800℃ for 2h, the particle size of γ-Al₂O₃ powder was less than 20nm, the α-Al₂O₃ could be obtained after calcining at 1000℃ for 2h, the particle size was 20-50nm.Secondly, the carbon microspheres was prepared by hydrothermal method, the glucose was used as carbon source, when the concentration of glucose was lmol/L, the void fraction was 30%, the carbon microspheres can be obtained by reacting at 180℃ for 8h. the particle size of carbon microspheres was about 600nm.Thirdly, the composite of carbon microspheres/amorphous aluminum hydroxide/carbon-coated layer can be obtained by hydrothermal method, the carbon microspheres was used as template, aluminum nitrate was used as source of aluminum, the tri-block copolymer （F127） was used as surfactant, The alumina hollow spheres can be obtained by calcining the composite at a proper temperature. The obtained alumina hollow spheres have the uniform thickness and good dispersion, the particle size was 700nm, and the thickness was about 100nm.