富硼过渡金属化合物TMBn的化学键特性和性能调控方法

项目名称： 富硼过渡金属化合物TMBn的化学键特性和性能调控方法

项目编号： No.U1435206

项目类型： 联合基金项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 周延春

作者单位： 航天材料及工艺研究所

项目金额： 500万元

中文摘要： 富硼过渡金属化合物TMBn(TM是过渡金属、n=2、4、6或12)，具有低密度、高熔点、高强度、结构和化学稳定性好、导热、导电、抗烧蚀和抗冲刷等优异性能，是高超声速飞行器热防护、太阳能有效吸收、热工设备高发射率辐射涂层的关键候选材料。但目前对这类化合物的电子结构、化学键特性及其对宏观性能的影响尚不清楚，使得在高超声速飞行器应用中面临的抗热冲击性差、热导率不高等问题难以解决，作为高发射率辐射涂层材料的机理和选材原则也不清楚。由于电子结构和化学键特性是决定其宏观性能的本质，d电子的轨道多样性和B价电子的特殊性使得化学键特性复杂多样并直接影响宏观性能，深入认识结构和性能关系，可实现对它们的抗热冲击性、吸收、辐射等性能的裁剪和调控。本项目拟在化学键特性研究和性能预测基础上，结合有选择的材料制备和性能验证，为这类材料在高超声速飞行器热防护、太阳能吸收和高发射率热辐射涂层等方面的应用提供理论依据。

中文关键词： 超高温陶瓷；力学性能；抗热震性；致密化；热导率

英文摘要： Boron rich transition metal borides TMBn, where TM is a transition metal, n=2,4,6 or 12, process a uinique combination of low desnsity, high melting point, high strength, good structural and chemical stability, good thermal and electrical conductivity,excellent ablation and erosion resistance, and are considered as candidate materials for thermal protection of hypersonic vehiecles, solar absorbtion, high efficiency thermal emition coating in high temperature furnaces. However，the electronic structure, chemical bonding nature and their effects on the macroscopic properties are not well understood. Due to the lack of knowledge on electronic structure,chimical bonding and properties , the poor thermal shock resistance, unsatisfied thermal conductivity are difficult to solve during applications as thermal protection materials in hypersonic vehiecales. The mechanism and material selection criteria are also not clear for thermal emission applications. It is well kownn that the macroscopic properties are underpined by the electronci structure and chemical bonding nature. The divise shapes of d orbitals in transition metals and charateristics of valence electron configuration of boron atoms make the electronic structure and chemical bonding more complex and divise, thus detailed invistigation on the structure-property relationships is helpful in tailoring the thermal shock resistance, absorption and emission properties of TMBn. The popurse of this work is to investigate the electronic structure and chemical bonding of TMBn, predict the mechanical, thermal and electrical properties combined with the material synthesis and property testing of selected materials, and provide theoretical basis for the applications of TMBn in hypersonic vehiecles, solar absorption and theral emission.

英文关键词： ultrahigh temperature ceramics;mechanical properties;thermal shock resistance;densification;thermal conductivity