高强度碳化硅泡沫陶瓷的制备及其抗压强度研究

选用Al2O3、Y2O3作为烧结助剂,通过有机模板复制法及多次浸渍涂覆工艺制备出高强度碳化硅泡沫陶瓷材料。系统地研究了原料组成、烧结温度等工艺参数对制得的碳化硅泡沫陶瓷物相组成、宏观结构、微观结构的影响,同时对陶瓷的气孔率、力学性能等进行了测试。结果表明:通过选取不同PPI值的有机泡沫模板,泡沫陶瓷宏观孔径可控;随着涂覆次数的增加,陶瓷体孔径减小、孔棱直径增加;随着烧结温度的提高,孔棱致密度增加,抗压强度显著提高;在1700℃下获得了20PPI值,气孔率为77%,抗压强度达2.48MPa的碳化硅泡沫陶瓷。

Preparation of High Strength Silicon Carbide Ceramic Foams and Their Compressive Strength

SiC ceramic foams with high strength were prepared using Al2O3 and Y2O3 as the sintering additives by polymer replica technique after various coating process. The effects of sintering additives, sintering temperature and holding time of the samples on the phase and macro/microstructure were analyzed. The strut density, porosity and mechanical properties of ceramic foams were characterized. The results show that with the increasing coating times, the pore size is decreased and the strut diameter is increased. The macro pore size can be controlled just by choosing different polymer sponge replicas with different PPI values. The strut density and compressive strength are increased significantly with the increasing sintering temperature. SiC ceramic foams with PPI value of 20, porosity of 77% and compressive strength of 2.48 MPa are obtained at 1700oC with the main phase of SiC.