Structure And Property Characterization Of Zirconium Diboride - Silicon Carbide Porous Ceramic Prepared By Freeze-casting

As a new type of inorganic material, porous ceramic receive increasing attention and has become the hot spots of ceramic materials research field. With low density , high temperature and corrosion resistance,high specific surface area, moderate strength, low thermal conductivity and other properties, porous ceramic is widely used in many fields, such as insulation, filtration and absorption ,acoustic noise ,biomedical materials and environmentally friendly building materials and other fields , for its high utility value and good prospects.In this paper, high purity zirconium diboride and silicon carbide ceramic powder are used as raw materials, camphene as forming medium, Texaphor963 as additives, after the thermostat milling process to get zirconium diboride - silicon carbide ceramic slurry, using the Freeze-Casting method to get ceramic body, after drying at room temperature to obtain a zirconium diboride - porous silicon carbide ceramics sintered with three-dimensional network structure. In the experiment, scanning electron microscopy, mercury intrusion method and compression strength testing and other methods were adopted to test the internal microstructure, pore morphology , mechanical properties and other characteristics of porous silicon carbide ceramics.In order to research the influence of the different initial solid content, the cooling mechanism, sintering schedule on the porous ceramic microstructures, a series of validation experiments were designed to research in this paper.The experiment results show that there are three parts of structure in the porous ceramic prepared by Freeze-Casting method, namely,a dense surface layer,transition regions and the central structure, and the difference of the structure are the result of crystallization morphology diversity of camphene at different solid content and cooling mechanisms.The condensation crystallization process of camphene are major in the growth of dendritic extension.The characteristics and mechanical properties of porous zirconium diboride- silicon carbide ceramics are studied, and analyzes the main influencing factors are also analyzed. The final conclusion confirm the pore size and porosity of zirconium diboride- silicon carbide porous ceramic are inverse relation with solid content and heat preservation time;compressive strength improves with the increase of solid content and sintering preservation time.