凝胶注模工艺制备莫来石泡沫陶瓷

Preparation of Mullite Foam Ceramics by Gelcasting

采用凝胶注模工艺，在陶瓷浆料发泡的基础上，通过有机单体的原位聚合固化制备莫来石泡沫陶瓷．研究了工艺条件对纯单体溶液、发泡和未发泡悬浮浆料等不同体系聚合反应的影响．聚合反应过程的温度变化曲线分析表明，单体溶液或浆料的pH值、初始温度和组成对其聚合反应有显著影响．制备的泡沫陶瓷为开孔贯通泡沫体，体积密度为理论密度的8%-40％，气孔率可达到90％以上，平均孔径范围和孔径分布范围分别为50-300μm和30-800μm显微结构分析表明，泡沫陶瓷平均孔径和孔径分布取决于聚合反应引发时间和泡沫陶瓷体积密度．

Gelcasting process, based on the foaming of aqueous ceramic suspension and subsequent solidification of the structure by in-situ polymerization of organic monomers, was introduced in the research for the preparation ofmullite foam ceramics. Parameters affecting the kinetics of different polymerization systems were investigated in systems containing the separate components of a ceramic solution, formed or unformed. Analysis of the temperature curves reveals that the onset of polymeric reactions is apparently affected by pH value, initial temperature and composition. The resulting foam ceramics consisted of a highly interconnected network of spherical cells with density 8%-40% of theoretical value and porosity above 90%. The mean pore size and its distribution of sintered foam ceramics were dependent both on the induction time of polymerisation and the bulk density of the specimen, and ranged from approximately 50 to 300 μm and 30 to 800 μm respectively.