Melting Studies of Core-forming Alloys

成芯合金的熔化研究

• 批准号: 1651017
• 负责人: Andrew Campbell
• 金额: $ 41.51万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1651017&HistoricalAwards=false
• 关键词: Melting; Studies; Core; forming; Alloys

The results expected from this project will improve our understanding of the temperature and chemical composition of Earth's core. Earth's core is known to be an iron-rich alloy, mostly molten but with a solid inner core. In addition to iron, it contains approximately 5% nickel and approximately 10% of a lighter element, whose identity is uncertain but is likely a combination of oxygen, sulfur, silicon, and/or carbon. A more precise understanding of the composition of Earth's core is important to deduce better the chemical and physical processes that led to the formation of our planet. An underutilized constraint on this problem is the density contrast at the solid inner core to liquid outer core boundary, where solidification has taken place over time. This density difference, determined by seismological studies to be approximately 7%, implies a subtantial compositional difference between the solid and liquid, and is not easily satisfied by existing phase diagrams of the relevant iron-rich systems. These phase diagrams are poorly known, however, and accordingly, the aims of this project are to obtain them by measuring the compositions of coexisting solid and liquid iron alloys under the extreme pressure, temperature conditions that exist in Earth's core. The experimental results will be applied to place more precise bounds on the composition of Earth's core. This research project will also serve as a platform for the training of graduate and undergraduate students in advanced laboratory research and scientific pursuit.The specific experimental research goals of this project are to measure the solid/melt phase relations in the Fe-O-S system up to pressures and temperatures comparable to those in Earth's deep interior (i.e. exceeding 200 GPa and 4000 K), using laser heated diamond anvil cell technology. The experiments will be performed in the Laboratory for Mineral Physics at the University of Chicago. Sample extraction and microanalysis will be performed using focused ion beam (FIB) and scanning electron microscopy (SEM). Selected samples may also be examined by transmission electron microscopy (TEM) as needed. The measured compositions of coexisting liquid and solid phases will be used to construct phase diagrams for the Fe-rich alloy systems. To augment the experiments, the results will be used to guide a thermodynamic description of the alloy systems; this will minimize the number of experiments needed as well as provide a framework for extrapolating / interpolating the results to pressure-temperature-composition points that are not directly studied by experiment.

该项目的预期结果将提高我们对地球核心温度和化学成分的理解。众所周知，地球的核心是铁富合金，主要是熔融，但具有固体内核。除铁外，它还包含约5％的镍和大约10％的较轻元素​​，其身份不确定，但可能是氧，硫，硅和/或碳的组合。对地球核心组成的更精确理解对于更好地推断导致地球形成的化学和物理过程很重要。对此问题的限制不足的约束是固体内核与液体外核边界的密度对比度，在液体外核边界中，随着时间的推移发生了凝固。通过地震学研究确定的这种密度差异约为7％，这意味着固体和液体之间的底部组成差异，并且不容易通过相关富铁的系统的现有相图来满足。但是，这些相图是鲜为人知的，因此，该项目的目的是通过测量在极端压力，地球核心中存在的温度条件下共存的固体和液态铁合金的组成来获得它们。实验结果将用于将更精确的边界放在地球核心的组成上。 This research project will also serve as a platform for the training of graduate and undergraduate students in advanced laboratory research and scientific pursuit.The specific experimental research goals of this project are to measure the solid/melt phase relations in the Fe-O-S system up to pressures and temperatures comparable to those in Earth's deep interior (i.e. exceeding 200 GPa and 4000 K), using laser heated diamond anvil cell technology.该实验将在芝加哥大学的矿产物理实验室中进行。样品提取和微分析将使用聚焦离子束（FIB）和扫描电子显微镜（SEM）进行。也可以根据需要通过透射电子显微镜（TEM）检查选定的样品。共存液相和固相的测得的组成将用于构建Fe丰富合金系统的相图。为了增加实验，结果将用于指导合金系统的热力学描述。这将最大程度地减少所需的实验数量，并提供一个框架，以推断 /插值结果到未直接通过实验直接研究的压力温度组成点。

项目成果

High-Pressure Geophysical Properties of Fcc Phase FeH X

Fcc相FeH X的高压地球物理性质

• DOI: 10.1002/2017gc007168
• 发表时间: 2018
• 期刊: Geosystems
• 作者: Thompson, E. C.;Davis, A. H.;Bi, W.;Zhao, J.;Alp, E. E.;Zhang, D.;Greenberg, E.;Prakapenka, V. B.;Campbell, A. J.
• 通讯作者: Campbell, A. J.

Phase transitions in ε-FeOOH at high pressure and ambient temperature

高压和环境温度下 ε-FeOOH 的相变

• DOI: 10.2138/am-2020-7468
• 发表时间: 2020
• 期刊: American Mineralogist
• 影响因子: 3.1
• 作者: Thompson, Elizabeth C.;Davis, Anne H.;Brauser, Nigel M.;Liu, Zhenxian;Prakapenka, Vitali B.;Campbell, Andrew J.
• 通讯作者: Campbell, Andrew J.

Elastic Properties of the Pyrite‐Type FeOOH‐AlOOH System From First‐Principles Calculations

根据第一原理计算黄铁矿型 FeOOH-AlOOH 体系的弹性性质

• DOI: 10.1029/2021gc009703
• 发表时间: 2021
• 期刊: Geosystems
• 作者: Thompson, Elizabeth C.;Campbell, Andrew J.;Tsuchiya, Jun
• 通讯作者: Tsuchiya, Jun