竹炭及SiC陶瓷材料的结构与性能

The micro-structure and properties of charcoal and SiC ceramics derived from bamboo

以毛竹、印度莿竹为原料,在氮气氛中炭化制得竹炭,然后于1450℃下采用熔融Si渗透技术制得SiC陶瓷材料。借助SEM、XRD、X射线能谱仪、TGA和万能力学试验机等测试手段对竹炭和SiC陶瓷材料的微观构造、物相构成、材料的微区成分、力学特性及竹材的热失重行为进行了分析。结果表明:竹炭及其SiC陶瓷材料都继承了竹材的各向异性和微观构造特征;竹基SiC陶瓷是一种包含单质Si、C和SiC多相成分的复合材料;由两种竹材制备的竹炭及其SiC材料在微观构造、相组成和抗压力学性能上表现出一定的差异性。

Two types of bamboo, i.e. Phyllostachys heterocycla, Bambusa arundinaeea, were selected as the raw materials to produce charcoal and SiC ceramics. First, biological carbon preforms were derived from bamboo by pyrolysis under N2 atmosphere, and then used as templates for molten silicon infiltration at 1450℃ in an argon atmosphere to form SiC ceramics. The pyrolysis process was studied by TGA, SEM, energy dispersive analysis of X-rays and XRD was used to characterize the microstructure, phases and physico-chemical structure changes during the wood -to-ceramic conversion. The compressive mechanical behavior of the bamboo-derived SiC materials was measured by a universal testing machine. Results show that the carbon preforms and the final SiC ceramics both inherit the anisotropic microstructure of bamboo. The SiC ceramics prepared by this technique are multi-phase solids composed of SiC, free-silicon and C. The SiC ceramic materials produced from these two bamboo species show differences in fracture, phase-composition and compressive strength.