基于烧绿石晶格的非谐振性及独特性提高其高温隔热性能及热膨胀匹配性的机理研究

项目名称： 基于烧绿石晶格的非谐振性及独特性提高其高温隔热性能及热膨胀匹配性的机理研究

项目编号： No.51502342

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 王衍飞

作者单位： 中国人民解放军国防科技大学

项目金额： 20万元

中文摘要： 航空发动机的发展迫切地需要开发有更高高温隔热性能、更高可靠性的下一代高温热障涂层。本项目基于具有优异高温稳定性的A2B2O7烧绿石陶瓷，围绕提高晶格的非谐振性，研究热障涂层材料的成分设计、制备工艺、微观结构、传热及热膨胀机理。利用烧绿石晶格的开放性和独特性，在晶格中引入氧空位、间隙离子以及共振子，分别通过高温拉曼光谱法、红外光谱法研究它们对晶格非谐振性、材料的吸收或散射系数等与辐射传热密切相关的光学性能的影响。另外，烧绿石晶格中与A紧密相连的二配位氧(O’)的横向振动造成了晶格收缩,拟引入与O’结合较弱的阳离子、间隙离子等，来改善烧绿石晶格的热膨胀行为。本项目的研究将进一步揭示陶瓷材料在高温下的传热机理，特别是晶格非谐振性对高温传热的影响；揭示陶瓷材料的逆向热膨胀现象及相应的抑制方法，为开发下一代高性能的高温热障涂层提供理论指导。

中文关键词： 烧绿石；热障涂层；晶格非谐振性；热膨胀；共振子

英文摘要： The development of aero-plane engines urgently needs the developments of the next-generation thermal barrier coatings (TBCs) with a more superior high-temperature insulating property as well as higher reliability. Based on A2B2O7 -type pyrochlore ceramics that have an excellent high-temperature stability, this project studies the composition design, fabrication methods, the microstructure and the fundamentals of thermally insulative and expansive properties of pyrochlores, with the aim to improve their lattice anharmonicity. By exploiting the openness and uniqueness of the pyrochlore lattice, oxygen vacancies, interstitials and rattlers are respectively introduced to the lattice. Their effects on lattice anharmonicity and the optical properties (such as absorption coefficient, scattering coefficient) that are closely related to the high-temperature radiative heat transfer are evaluated by the high-temperature Raman spectroscopy and infrared spectroscopy respectively. In addition, the transverse vibration of double-coordinated oxygen (O’) that are tightly connected to A leads to the lattice shrinkage. This negative thermal expansion coefficient is proposed to be relieved by connecting O’ with a weaker bond, or introducing interstitials near O’. The study of this project will further unveil the heat conduction mechanism of ceramics at high temperatures, particularly the effect of lattice anharmonicity on high-temperature heat transfer, as well as the negative thermal expansion in ceramics and the corresponding strategy to relieve its impact, and will provide theoretical guidance to the developing of next-generation high-temperature thermal barrier coatings with superior properties.

英文关键词： pyrochlore;thermal barrier coatings;lattice anharmonicity;thermal expansion;rattler