The Preparation And Characterization Of Inorganic Micropores Substrate Membrane

The arm of this research is to prepare inorganic micropores substrate membrane, we will mainly study the principle of fonnation and process as well as characterization methods about pore structure, transfer, fractals, statistical models of inorganic membranes.The micropores membranes prepared by the solid state sintering technology belongs to quadratic pores membrane, so it obeys the formation law of quadratic pores. The quadratic pores fonnation is influenced by two main factors: one is the particle-size of powders, another is the particle packing of powders. The powders can be graded by sieving and hydroelectric subsidence in some size distribution, sieving just apply to above 30pm powders and hydroelectric subsidence may for 1³0μm powders, for making more fine powders, the ultrafine powders preparing technology is required, for example, less than 1μm Al₂O₃ ultrafine powders can be made by pyrotysis of ammonium aluminum sulfate. There are four type important particle packing pattern of powders: concentrated packing, bridge packing, vacant packing and growth packing, they can be controlled by different process, they also can influence the formation of quadratic pore in some way, so particle-size and particle packing patterns of powders become two important method to control the performance of micropores membrane.Experiment shows that the pore size, porosity and permeation of membrane will decrease as the powders becoming small, but the porosity is influenced more by the particle packing pattern of powders. Fonning process of substrate membrane mainly include dried pressing, slip-casting and extrusion etc. Forming process can control the particle-packing of powders, for example, in dried pressing and extrusion process, concentrated packing will appear because the powders are extruded by mechanical power, and bridge packing will also appear in slip-casting process, so for growth packing appear in Sol-Gel process and vacant packing appear by adding pore-forming material. Different forming process will have different influence on the performance of membrane.Temperature is a very important factor to influence the quadratic pore membrane, mainly because the particle-packing pattern of powders will change under high temperature. Sintering process in only way to let membrane have mechanical strength, the choice of sintering temperature must assure the neck...