非晶态SiCN陶瓷的高温电导率

HIGH TEMPERATURE CONDUCTIVITY OF AMORPHOUS SiCN CERAMICS

采用直流电流电压测试方法,测定了热裂解前驱体方法制得的SiCN非晶态陶瓷在室温至1373K范围内的直流电导率。结果表明:电导率从室温时的9.6×10-9(Ω·cm)-1增加到1373K时的1.62×10-3(Ω·cm)-1。用Mott模型和Arrhenius法则对实验数据进行分析表明:扩展态、带尾局域态、缺陷局域态、Mott模型中的变程跃迁都对样品的电导率有影响。X射线衍射结果表明:1473K热处理的样品为非晶结构。红外吸收谱表明:样品中主要键合方式为Si—C,Si—N和C—N键,仅有少量的C—H、Si—H和C—O键出现。

Temperature dependence of direct conductivity in amorphous SiCN ceramics obtained by pyrolysis of the polymer precursor was investigated in the temperature range of room temperature to 1373 K. The results indicate that the conductivity increases from 9.6×10-9 (Ω&middotcm)-1 at an ambient temperature to 1.62×10-3 (Ω&middotcm)-1 at 1373 K. The experimental data were analyzed by Mott model and Arrhenius law. Distinct electrical conduction mechanisms are contributed to the conductivity in experimental temperature range including variable range hopping, hopping near the Feimi energy, hopping in the band tail state and the conduction in the extended band. X-ray diffraction pattern indicates that the structure of the samples annealed at 1473 K is amorphous. Infrared spectroscopy analysis indicates that Si-C, Si-N and C-N bonds are the dominant chemical bonds, and fewer C-H, Si-H and C-O bands are found.