Development of Giant Diamonds from Chemical Vapor Deposition for High-Pressure Research

用于高压研究的化学气相沉积巨型钻石的开发

• 批准号: 0550040
• 负责人: Russell Hemley
• 金额: $ 95.85万
• 依托单位: Carnegie Institution of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0550040&HistoricalAwards=false
• 关键词: Development; Giant; Diamonds; Chemical; Vapor

0550040HemleyThis grant provides support for a three year development program aimed at fabrication of large (up to 250 carat) single crystal diamonds by novel chemical vapor deposition (CVD) techniques, the development of "designer" diamond anvils for high pressure/high temperature experimentation in the diamond anvil cell (DAC), and the development of new gaskets and presses for use in large volume DAC experiments at the Geophyscial Lab, Carnegie Institution of Washington. Characterization of the physical, chemical, electrical and mechanical properties of deep earth (lower mantle and core) materials, and properties of gases found within the interiors the giant gas planets (e.g. Jupiter and Saturn) can only be carried out in situ at extreme pressures ( 100-350 GPa) that have been demonstrated in successful DAC experiments. Diamond anvils offer extreme hardness, allowing for megabar pressures to be obtained in pressed cell experiments, high thermal diffusivity that allows for extreme temperature conditions with laser heating, and optical transparency that is ideal for x-ray diffraction and spectroscopic interrogation of high P/T phases in situ. Currently DAC experiments are limited to analysis of the properties of miniscule sample sizes that can be accommodates within flawless natural diamond anvils of limited size (e.g., 0.25 - 2.5 ct). Flawless natural diamonds are very expensive (ca. $1,000 for a 0.25 ct diamond up to $100K for a 2.5 ct diamond) and larger flawless diamond costs increase quadratically with carat weight. Natural flawless diamonds in excess of 25 carats have not been demonstrated to exist in nature. A recently acquired a next generation 6 kW microwave CVD plasma system chamber at CIW-GL is anticvpated to make possible the rapid growth of large ( 10 - 100 ct), flawless, single crystal diamond that could open a new frontier in the study of materials at extremes of pressures and temperatures. Affordable and structurally and optically optimized larger diamonds would afford experimentation with new anvil culet shapes and novel gasket designs. Also, CVD grown diamonds can be manufactured with embedded sensors to make available "designer" anvils for specialized experiments (e.g., magnetic, electrical, and elastic properties characterization of lower mantle and core phases). The goal of this projects is to develop new classes of high-pressure devices that will allow an increase in sample volumes up to 100 to 1000 times that currently available in conventional diamond cells at megabar pressures. The developments will facilitate numerous x-ray based analytical techniques currently unavailable for ultrahigh-pressure research, including those required for the successful utilization of major new neutron (SNS at Oak Ridge) and existing 2nd and 3rd generation synchrotron radiation facilities worldwide (e.g., APS/ANL, BNL, ESRF, SPring-8). Successful development of these new classes of high-pressure cells will allow for novel experiments in high pressure geoscience, planetary and materials science. The project will engage two graduate students in novel instrument design and mineral physics research applications and will prepare them for a diverse range of possible careers in academia, national laboratories, and industry. Beyond geoscience, the study of the electrical, optical and physical properties of materials at extremes of pressure promises novel technological spin offs with profound societal impact (e.g., new classes of CPU chip materials with thermal and electromagnetic properties that can accommodate continued advances in micro-circuitry). ***

0550040赫姆利这笔赠款为一项为期三年的开发计划提供支持，该计划旨在制造大型（最高250克拉）单晶金刚石，“设计师”金刚石砧的开发，用于金刚石砧室（DAC）中的高压/高温实验，以及华盛顿卡内基研究所地球物理实验室用于大体积DAC实验的新垫圈和压力机的开发。 对地球深部（下地幔和地核）物质的物理、化学、电学和机械特性以及在巨型气体行星（如木星和土星）内部发现的气体特性的表征只能在极端压力（100-350 GPa）下就地进行，这已在成功的DAC实验中得到证明。 金刚石砧提供极高的硬度，允许在压室实验中获得兆巴压力，高热扩散率，允许在激光加热的极端温度条件下使用，以及光学透明度，非常适合X射线衍射和原位高P/T相的光谱询问。 目前，DAC实验仅限于分析可容纳在有限尺寸的无瑕疵天然金刚石砧内的微小样品尺寸的性质（例如，0.25-2.5ct）。 完美无瑕的天然钻石是非常昂贵的（CA。0.25克拉的钻石为1,000美元，2.5克拉的钻石为10万美元），而更大的无瑕钻石的成本随着克拉重量的平方增加。 超过25克拉的天然无瑕钻石尚未被证明存在于自然界中。 CIW-GL最近收购的下一代6 kW微波CVD等离子体系统腔室使大（10 - 100 ct），无瑕疵，单晶金刚石的快速生长成为可能，这可能在极端压力和温度下开辟材料研究的新前沿。 负担得起的和结构和光学优化的较大的钻石将提供实验与新的砧底脚形状和新颖的垫圈设计。 此外，CVD生长的金刚石可以用嵌入式传感器制造，以使“设计师”砧可用于专门的实验（例如，下地幔和地核相的磁、电和弹性特性表征）。 该项目的目标是开发新型高压装置，使样品体积增加到目前在兆巴压力下传统金刚石细胞中可用的100至1000倍。 这些发展将促进目前无法用于超高压研究的许多基于X射线的分析技术，包括成功利用主要新中子（橡树岭的SNS）和全球现有的第二代和第三代同步辐射设施（例如，APS/ANL、BNL、ESRF、SPring-8）。 这些新型高压电池的成功开发将允许在高压地球科学，行星和材料科学中进行新的实验。该项目将让两名研究生从事新型仪器设计和矿物物理研究应用，并为他们在学术界，国家实验室和工业界的各种可能的职业生涯做好准备。 除了地球科学之外，对极端压力下材料的电学、光学和物理特性的研究有望带来具有深远社会影响的新技术衍生产品（例如，具有热和电磁特性的新型CPU芯片材料，可以适应微电路的持续发展）。 ***