Search and Characterization of Noval Superhard Phases in the B-C-N System Under Extreme Conditions

极端条件下B-C-N体系中新型超硬相的搜索与表征

• 批准号: 0102215
• 负责人: Li Chung Ming
• 金额: $ 34.76万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0102215&HistoricalAwards=false
• 关键词: Search; Characterization; Noval; Superhard; Phases

0102215MingIn the proposed research, formation of the theoretically predicted new dense phases in the B-C-N composition triangle will be systematically examined over a wide pressure and temperature range using laser heated diamond anvil cell (up to 1x 106 atm or 14.7 x 106 psi and 2500oC) as well as large-volume high P-T apparatus (up to 3x 105 atm or 44.1 x 105 psi and 2000oC). The structures and properties of quenched samples will be analyzed by powder x-ray diffraction, electron microscopy, hardness measurements, and optical and acoustical methods. The overall scientific goals of the project are: (1) synthesis of novel superhard phases in the B-C-N system at high pressures and high temperatures by direct conversion of layered B-C-N phases, (2) investigation of physico-chemical and structural properties of the end-products at ambient conditions, and (3) characterization of elastic and vibrational properties of novel phase(s) at high pressures up to 1x 106 atm (14.7 x 106 psi) and at room temperature. %%%The proposed research will provide valuable data that will be used to identify main features of the phase transformations observed in the B-C-N system at high pressures and temperatures, and the factors responsible for formation of superhard B-C-N phases. These results will enhance our understanding of the fundamental problem in development of new superhard materials and will provide a sound basis of developing and producing new super-abrasives that are thermally and chemically more stable than diamond, and harder than cubic BN, enabling major advances in the cutting and polishing industries.

0102215明在所提出的研究中，我们将利用激光加热金刚石对顶砧，在较宽的压力和温度范围内，系统地研究理论预测的B-C-N组成三角形中新致密相的形成（高达1x 106 atm或14.7 x 106 psi和2500 oC）以及大容量高P-T装置（高达3x 105 atm或44.1 x 105 psi和2000 oC）。淬火样品的结构和性能将通过粉末X射线衍射、电子显微镜、硬度测量以及光学和声学方法进行分析。 该项目的总体科学目标是：（1）通过层状B-C-N相的直接转化，在高压和高温下在B-C-N系统中合成新型超硬相，（2）在环境条件下研究最终产物的物理化学和结构性质，和（3）在高达1 × 106 atm（14.7 × 106 psi）的高压和室温下表征新相的弹性和振动性质。 这项研究将提供有价值的数据，用于确定在高压和高温下观察到的B-C-N系统相变的主要特征，以及形成超硬B-C-N相的因素。这些结果将增强我们对开发新超硬材料的基本问题的理解，并将为开发和生产新的超硬磨料提供良好的基础，这些磨料的热稳定性和化学稳定性比金刚石更好，比立方氮化硼更硬，从而使切削和抛光行业取得重大进展。