Synthesis of porous silicon nitride with unidirectionally aligned channels using freeze-drying process
Synthesis of porous silicon nitride with unidirectionally aligned channels using freeze-drying process
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DOI：
10.1111/j.1151-2916.2002.tb00426.x
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发表时间：
2002-09-01
影响因子：
3.9
通讯作者：
Kanzaki, S
中科院分区：
文献类型：
--
作者：
Fukasawa, T;Deng, ZY;Kanzaki, S
采用冷冻干燥法制备了具有宏观取向通道的多孔氮化硅。在单向控制冰的生长方向的同时，冻结了氮化硅的水基浆料。在冷冻干燥过程中，柱状冰的升华会产生气孔。通过该坯体的烧结，获得了孔隙率较高(50%以上)的多孔氮化硅，其孔隙率可通过浆料浓度控制。多孔的Si3N4具有独特的微观结构，宏观上排列的开放气孔包含从Si3N4基质内壁突出的纤维颗粒。推测气/固相反应对纤维状颗粒的形成机制具有重要作用。
Porous silicon nitride with macroscopically aligned channels was synthesized using a freeze-drying process. Freezing of a water-based slurry of silicon nitride was done while unidirectionally controlling the growth direction of the ice. Pores were generated subsequently by sublimation of the columnar ice during freeze-drying. By sintering this green body, a porous silicon nitride with high porosity (over 50%) was obtained and its porosity was controllable by the slurry concentration. The porous Si3N4 had a unique microstructure, where macroscopically aligned open pores contained fibrous grains protruding from the internal walls of the Si3N4 matrix. It is hypothesized that vapor/solid phase reactions were important to the formation mechanism of the fibrous grains.