Abstract: High thermal-stable alumina-substrate materials were prepared by the reverse microemulsion method and characterized by XRD, nitrogen
adsorption at low temperature, TEM and so on. The results indicate that the samples prepared by the reverse microemulsion method have
higher thermal stability. After calcination at 1100℃ for 10h, the surface area of alumina, Ba-doped alumina and Si-doped alumina is
51, 90 and 175m²·g^-1 respectively, which is much higher than that of the same samples prepared by the sol-gel method. Besides this, the phase structures and the pore diameter distribution of the sample
derived from the reverse microemulsion method are also more different to those of the sample derived from the sol-gel method. The former
shows transition alumina structure and uniform nanometer particles even calcined at 1100℃ for 10h. The presence of Ba or Si can
increase the phase transformation temperature of alumina and restrict its grain growth at high temperature.

Key words: reverse microemulsion method, high thermal-stability, nano-alumina, preparation