The synthesis of alumina membrane with interconnected uniform pores from inactive spheres

In this work, the interlayer and top-layer of alumina membrane are synthesized on substrate by one-step sintering process, and the microstructure evolution and mass transfer characterization of top-layer synthesized from sub-micrometer spheres is fully investigated. It shows that the pores in top-layer of membrane are interconnected and uniform and their microstructure evolution can be controlled by adjusting the sintering temperature in a wide range. Kinetics analysis of the sintering behavior shows that the superior thermostability of spheres can eliminate the rapid uneven shrinkage of membrane and result in the uniform microstructures. In addition, it is found that the mass transfer among spheres with polycrystalline phases of and cannot occur unless these metastable phases transform to stable -Al2O3, which is favorable to sinter at the same temperature range with the interlayer. Moreover, the effect of phase composition on mass transfer is further put forward. Finally, solid/water mixture has been processed by the synthesized membrane and the excellent filter performance confirms the uniform pores.