An improved gel-casting procedure was successfully exploited to produce porous ceramic bodies having controlled porosity features in terms of mean pore size, total pore volume as well as pore geometry. The gel-casting process in which a natural gelatine for food industry is used as gelling agent was firstly set-up to prepare dense alumina and zirconia components, by using two commercial powders, precisely TM-DAR Taimicron alumina and TOSOH TZ-3YS zirconia. To prepare porous components, commercial polyethylene (PE) spheres, sieved to select proper dimensional ranges, were added to the ceramic slurries as pore-forming agent. In the case of zirconia, components having 50 vol. percent porosity were prepared by using PE spheres in the size range 125-300 mu m. For alumina porous materials, three different porosity percentages were investigated, precisely 40, 50 and 60 vol. percent, using PE spheres in the range 224-300 mu m. A suitable thermal treatment was set-up for burning-out the organic phases (PE and gelatine) and subsequent densification of the ceramic network. The fired components presented spherical pores surrounded by highly dense ceramic walls and struts, having a homogeneous and fine microstructure. The mean pore size was directly dependent on the adopted sieved fraction of PE spheres. Hg porosimetry was coupled to image analyses performed on SEM micrographs for a full characterization of the porosity features.
展开▼
机译：成功地利用改善的凝胶铸造程序，以产生具有受控孔隙率特征的多孔陶瓷体，其平均孔径，总孔体积以及孔隙几何形状。凝胶铸造方法，其中用于食品工业的天然明胶作为胶凝剂，首先通过使用两种商用粉末制备致密的氧化铝和氧化锆组分，精确地TM-DAR Taimicron氧化铝和陶富特TZ-3MY氧化锆。为了制备多孔组分，将用于选择适当尺寸范围的商业聚乙烯（PE）球体作为孔形成剂加入陶瓷浆料中。在氧化锆的情况下，具有50体积的组分。通过使用尺寸范围为125-300μm的PE球体来制备孔隙率百分比。对于氧化铝多孔材料，研究了三种不同的孔隙率百分比，精确为40,50和60体积。百分比，使用224-300 mu m范围内的pe球体。设置合适的热处理，用于燃烧有机相（PE和明胶）和随后的陶瓷网络的致密化。烧制的部件呈现由高度密集的陶瓷壁和支柱围绕的球形孔，具有均匀和精细的微观结构。平均孔径直接依赖于所采用的PE球体的筛分分数。 Hg孔隙辛法与在SEM显微照片上进行的图像分析偶联，以满足孔隙率特征。
展开▼
