Compressibility and Structure of Silicate Melts at High Pressure

高压硅酸盐熔体的压缩性和结构

• 批准号: 0538884
• 负责人: Murli Manghnani
• 金额: $ 30万
• 依托单位: University of Hawaii
• 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: 2006-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0538884&HistoricalAwards=false
• 关键词: Compressibility; Structure; Silicate; Melts; Pressure

This project involves a laboratory investigation of the elastic properties and structure of hydrated and anhydrous alkali silicate melts under in-situ high pressure and temperature conditions in the externally heated diamond anvil cell (DAC) by Brillouin light scattering (BLS) technique. This technique allows measurements of both VP and nVP (where VP is compressional velocity and n is refractive index) simultaneously by a "modified" Brillouin platelet scattering geometry in diamond anvil cell,In conjunction with the Brillouin measurements, the investigators are also carrying out Raman scattering studies in order to correlate the measured elastic properties with the structure of the melt. These studies are conducted on hydrated and anhydrous alkali silicates with a range of cation sizes and different degrees of melt polymerization. As such, these data are enabling to constrain the structural systematics of melt elasticity at pressure, providing insight into the role of pressure-induced changes as well as water inmelt structure in altering melt compressibility. One major goal is to compare the possible structural and elastic changes occurring in both silicic (silica-rich) and mafic (iron-rich) melts under compression. The other major scientific goal is to carry out the in situ high P-T DAC experiments, involving both Brillouin and synchrotron x-ray microtomography simultaneously, at the GSECARS beam line of the Advanced Photon Source, Argonne National Laboratory, for determining the elastic properties (compressibility and densification) of silicate melts more precisely,Pursuing technically challenging and intellectually stimulating questions are expected to sufficiently sharpen scientific acumen of students and post-doctoral researchers involved, so they will become the next generation of scientists. The success of this study has potential value in future high P-T light scattering experiments in the DAC, and is expected to impact Earth and materials sciences and engineering, providing useful implications for society, industry, and defense needs.

本项目采用布里渊光散射（Brillouin light scattering，BLS）技术，在外加热金刚石对顶砧装置（DAC）中，对水合和无水碱金属硅酸盐熔体在高温高压条件下的弹性性质和结构进行了实验室研究。这种技术允许测量VP和nVP（其中VP是压缩速度和n是折射率），同时通过“修改”布里渊血小板散射几何形状在金刚石砧室，结合布里渊测量，研究人员还进行了拉曼散射研究，以关联测量的弹性性能与熔体的结构。这些研究是在具有一系列阳离子尺寸和不同熔融聚合度的水合和无水碱金属硅酸盐上进行的。因此，这些数据能够约束熔体弹性在压力下的结构系统学，提供洞察力的作用，压力引起的变化，以及水inmelt结构在改变熔体的可压缩性。一个主要的目标是比较可能的结构和弹性的变化发生在两个镁铁质（富硅）和镁铁质（富铁）熔体压缩。另一个主要的科学目标是在阿贡国家实验室先进光子源的GSECARS光束线上进行现场高P-T DAC实验，同时涉及布里渊和同步X射线显微层析成像，以确定弹性性质（可压缩性和致密化）更精确地，追求技术上具有挑战性和智力刺激的问题，预计将充分提高学生和博士后研究人员的科学敏锐性，他们将成为下一代科学家。这项研究的成功对DAC未来的高P-T光散射实验具有潜在价值，预计将影响地球和材料科学与工程，为社会，工业和国防需求提供有用的启示。