导电蒙脱石基陶瓷/碳复合材料的制备与性能

Preparation and properties of conductive montmorillonite-based ceramic/carbon composites

针对陶瓷材料结构-功能一体化,提出先以蒙脱石为模板,葡萄糖为碳源,采用溶液吸附的方法制备蒙脱石-葡萄糖;然后调控葡萄糖溶液的浓度,热压烧结蒙脱石-葡萄糖得到蒙脱石基陶瓷/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蒙脱石中葡萄糖的含量对陶瓷/碳复合材料的气孔率、力学性能和导电性能的影响。结果表明:蒙脱石吸附的葡萄糖在热压过程中原位碳化,增加了陶瓷/碳复合材料的显气孔率,导致弯曲强度和断裂韧性降低,但显著提高了陶瓷/碳复合材料的电导率。当葡萄糖溶液的质量分数为10%时,陶瓷/碳复合材料的碳质量分数为7.62%,电导率达到0.523S·m^(-1)。蒙脱石表面和层间的葡萄糖原位碳化,形成导电网络,促进了载流子的有效传递。在26.5~40 GHz频率范围内,获得的陶瓷/碳(碳质量分数为7.62%)最佳反射损耗为-41.35 dB,具有良好的吸波性能。

Montmorillonite based ceramic/carbon composites with good mechanical and conductive properties were prepared by hot pressing of glucose adsorbed montmorillonite. The adsorption contents of glucose was adjusted to control carbon contents in the ceramic composites. Effects of carbon content on apparent porosity,mechanical properties and electrical conductivity of ceramic/carbon were characterized by Archimedes drainage method, three-point bending test and SEM. The results show that the apparent porosity of the ceramic/carbon composites increases with the increase of carbon content, while the flexural strength and fracture toughness decrease. The electrical conductivity of the ceramic/carbon composite was highly improved. When the mass fraction of glucose solution was 10%, the carbon mass fraction of the ceramic/carbon composite was 7.62%, and the conductivity value was 0.523 S·m^(-1). In situ carbonization of glucose on the surface and between layers of montmorillonite results in the formation of conductive network, which promotes effective carrier transfer. For ceramic/carbon with carbon mass fraction of 7.62 %, the best reflection loss is-41.35 dB under 26.5-40 GHz frequency, which indicates its good wave adsorption performance.