水热-热压耦合法制备陶瓷/碳复合材料及其性能研究

Preparation of halloysite-based ceramic/carbon composites by hydrothermal-hot pressing coupling method and study on properties

以埃洛石为模板、壳聚糖为碳源,通过水热制备埃洛石/碳;调控两者的质量比,热压得到陶瓷/碳复合材料。采用阿基米德排水法、三点弯曲测试和扫描电镜等研究埃洛石表面碳质量分数对复合材料的致密度、力学和导电性能的影响。结果表明,碳在热压中进一步碳化,埃洛石转变为莫来石,复合材料中碳均匀分布;随着埃洛石表面碳质量分数的增加,复合材料内部微裂纹增多,弯曲强度逐渐降低,但少量碳的添加增加了陶瓷的断裂韧性;当m(埃洛石)∶m(壳聚糖)为8时,复合材料的断裂韧性最高,比不添加碳的陶瓷提高了12.93%;当m(埃洛石)∶m(壳聚糖)为2时,复合材料的电导率最高,达到23.15 S/m。

Halloysite/carbon are prepared by hydrothermal method using halloysite as template and chitosan as carbon source.By adjusting the mass ratio of halloysite to chitosan,ceramic/carbon composites are prepared by hot pressing sintering.The effects of carbon content on the density,mechanical property and electrical conductivity of composites are probed by Archimedes drainage method,three-point bending test and SEM.The results show that further carbonization occurs for the deposited carbon on halloysite surface,and halloysite transfers to mullite during hot pressing.Carbon is uniformly distributed in ceramic.With the increase of carbon content on the surface of halloysite,the generation of internal microcracks in composites increases and the flexural strength of the composites decreases gradually.Adding a small amount of carbon can improve the fracture toughness of ceramic.When the mass ratio of halloysite to chitosan is 8,the fracture toughness of the composite reaches the highest,which is 12.93%higher than that of the ceramic without carbon.When the mass ratio of halloysite to chitosan is 2,the electrical conductivity of composite achieves the highest,being 23.15 S·m^(-1).