硅溶胶分散氧化铝浆料的免脱气注凝成型工艺  

GELCASTING OF ALUMINA SLURRY DISPERSED IN SILICA SOL WITHOUT DE-AIRING PROCESS

作　　者：孔德玉[1] 杨辉[1] 韦苏[2] 李冬云[1] 

机构地区：[1]浙江大学材料与化工学院,杭州310027 [2]浙江工业大学建筑工程学院,杭州310014

出　　处：《硅酸盐学报》2005年第9期1070-1074,共5页Journal of The Chinese Ceramic Society

摘　　要：基于气泡的稳定性理论,发展了一种免脱气注凝成型技术制备莫来石陶瓷素坯。利用pH约为9.5的硅溶胶对氧化铝颗粒的分散作用,制备了固相体积分数为50%,浆料粘度为953 mPa.s的符合莫来石计量组成的硅溶胶分散氧化铝浆料。采用NH4Cl作为电解质,直接利用硅溶胶凝胶化实现浆料的原位凝固成型。研究发现:由于在浆料中不引入任何表面活性物质,浆料脱气处理时间对成型素坯气孔率影响不大,浆料无须经过脱气处理,即可成型得到抗折强度达4.83 MPa、显微结构致密均匀的莫来石素坯。A novel gelcasting technique without a de-airing step was developed to prepare mullite green body based on the mechanism of stabilization of bubbles entrapped in the slurry. Utilizing the scattering action of alumina particles in a silica sol at a pH value of about 9.5, an alumina slurry dispersed in the silica sol with a chemical composition of stoichiometric pure mullite, with a solid volume loading of 50 % and with viscosity as low as 953 mPa ·s was prepared. In situ consolidation of the slurry was accomplished by adjusting the concentration of NH4Cl to control the gelation time of the slurry. The results show that the de-airing time of the slurry has little effect on the porosity of the green body, because no surfactant is introduced into the slurry. A defect-free dried green body with a bending strength of 4.83 MPa can be obtained by this gelcasting technique without deairing.

关 键 词：注凝 硅溶胶 氧化铝 莫来石 

分 类 号：TQ174[化学工程—陶瓷工业]