STURCTURAL CHARACTERISTICS AND QUANTUM CHEMISTRY CALCULATION OF AI-DOPED BORON CARBIDES

作     者：安继明 

作者机构：Wuhan University of Technology China Natl. Key Lab. Adv. Technol. Mat. S. Wuhan University of Technology Wuhan 430070 China 

出 版 物：《Journal of Wuhan University of Technology(Materials Science)》 (武汉理工大学学报（材料科学英文版）)

年 卷 期：2000年第15卷第3期

页      面：27-32,46页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：Funded by the National Science Foundation of China Through Outstanding Youth Scientist Foundation (No. 59825102) and Science Foundation of Hubei Province(No. 98J028) 

主　　题：quantum chemistry structural characteristics boron carbides 

摘      要：Structural characteristics, chemical bonds and thermoelectric properties of Al-doped boron carbides are studied through calculations of various structural unit models by using a self-consistent-field discrete variation X. method. The calculations show that Al atom doped in boron carbide is in preference to substituting B or C atoms on the end of boron carbide chain, and then may occupy interstitial sites, but it is difficult for Al to substitute B or C atom in the centers of the chain or in the icosahedra. A representative structural unit containing an Al atom is [C - B -Al]-[B11C]-,while the structural unit without Al is [C-B-B(C)]- - [B11C]C+, and the coexistence of these two different structural units makes the electrical conductivity increased. As the covalent bond of Al-B or Al-C is weaker than that of B-B or B-C, the thermal conductivity decreases when Al is added into boron carbides. With the electrical conductivity increasing and the thermal conductivity decreases, Al doping has significant effect on thermoelectric properties of baron carbides.