Mechanochemical Processes dictating Calcite's Frictional Characteristics

决定方解石摩擦特性的机械化学过程

基本信息

批准号：
1856525
负责人：
Rosa Espinosa-Marzal
金额：
$ 32.39万
依托单位：
University of Illinois at Urbana-Champaign
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-15 至 2025-06-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1856525&HistoricalAwards=false
关键词：
Mechanochemical Processes dictating Calcite Frictional

项目摘要

Earthquakes are recurring and devastating events. To predict accurately their occurrence and magnitude remains, however, difficult. This is because the mechanisms underlying the rupture of earthquake-generating faults are not fully understood. Water plays an important role in fault dynamics; yet, the complexity of fault interfaces has hindered identifying the specific mechanisms influencing fault behaviors. Here, the researchers investigate the frictional strength of calcite - a mineral found in fault gouges - in aqueous environment. To study the effects of water-rich fluids, they use an idealized grain interface consisting of two 1-mm single crystals sliding against each other, with or without fluids in between them. The interface contains asperity contacts characterized at the microscale by atomic force microscopy. The study is relevant to natural faults because the stresses and slip rates applied to the interface are comparable to those of geological settings. Frictional characteristics are quantified using a new technique which measures displacements with an accuracy of 1 angstrom (0.1 millionth of a mm). This allows investigating the involved mechanisms, such as crystal dissolution/recrystallization on contacts. The project's results improve models of fault friction, which contributes improving the assessment of seismic hazards in the presence of reactive fluids. This project promotes support for a graduate student, training for undergraduate students and outreach to K-12 students, notably from groups underrepresented in Science. The team follows two main lines of research. At the experimental level, the project advances the knowledge of mechano-chemical interfacial reactions and their influence on calcite's frictional characteristics. It informs the mechanisms underlying pressure-solution at grain boundaries. The influence of different factors is evaluated: fluid chemistry, surface electric potential, the presence of phyllosilicates or confined fluid films. The effects of sliding velocity, stress, temperature, contact time and topography, on friction and adhesion are also quantified. Essential to this work is a modification of the Surface Forces Apparatus. The new development allows measuring creep deformation at wet calcite contacts with a precision of 0.1 nm, as well as interfacial forces (disjoining pressure, adhesion and friction). This provides insight on the relationship between pressure-solution creep and static and dynamic friction over a wide range of conditions. The simple geometry of the experiments allows to investigate the microscopic mechanisms responsible for macroscopic friction, and to test the theories that describe them. At the theoretical level, friction at single- and multi-asperity contacts are modeled based on the shear-assisted thermally activated slip theory, accounting for contact aging due to pressure-solution creep. The new model parameters are compared to and tested against the rate-and-state friction constitutive equations and their empirical parameters. The project, thus, fills the gap between the microscopic and the macroscopic scales in the understanding of fault friction in aqueous environment.This award is co-funded by the Prediction of and Resilience against Extreme Events (PREEVENTS) program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

地震是反复发生的破坏性事件。然而，准确预测它们的发生和程度仍然很困难。这是因为地震断层破裂的机制尚不完全清楚。水在断层动力学中起着重要作用；然而，故障接口的复杂性阻碍了识别影响故障行为的具体机制。在这里，研究人员研究了方解石（一种在断层泥中发现的矿物）在水环境中的摩擦强度。为了研究富含水的流体的影响，他们使用了理想化的颗粒界面，该界面由两个相互滑动的 1 毫米单晶组成，它们之间有或没有流体。该界面包含通过原子力显微镜在微观尺度上表征的粗糙接触。这项研究与自然断层相关，因为施加到界面上的应力和滑移率与地质环境下的应力和滑移率相当。使用新技术对摩擦特性进行量化，该技术测量位移的精度为 1 埃（百万分之 0.1 毫米）。这允许研究所涉及的机制，例如接触上的晶体溶解/重结晶。该项目的结果改进了断层摩擦模型，这有助于改进对存在反应流体的地震灾害的评估。该项目促进对研究生的支持、对本科生的培训以及对 K-12 学生的宣传，特别是来自科学领域代表性不足的群体的学生。该团队遵循两条主要研究路线。在实验层面，该项目推进了机械化学界面反应及其对方解石摩擦特性影响的认识。它揭示了晶界处压力溶解的潜在机制。评估不同因素的影响：流体化学、表面电势、页硅酸盐或受限流体膜的存在。滑动速度、应力、温度、接触时间和地形对摩擦和粘附的影响也被量化。这项工作的关键是对表面力装置的修改。新的开发成果能够以 0.1 nm 的精度测量湿方解石接触处的蠕变变形以及界面力（分离压力、粘附力和摩擦力）。这提供了对各种条件下压力溶液蠕变与静摩擦和动摩擦之间关系的深入了解。实验的简单几何结构允许研究导致宏观摩擦的微观机制，并测试描述它们的理论。在理论层面上，基于剪切辅助热激活滑移理论对单粗糙体接触和多粗糙体接触处的摩擦进行建模，并考虑了压力溶液蠕变导致的接触老化。新模型参数与速率和状态摩擦本构方程及其经验参数进行了比较和测试。因此，该项目填补了对水环境中断层摩擦理解的微观和宏观尺度之间的空白。该奖项由极端事件预测和恢复力 (PREEVENTS) 计划共同资助。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Nanoscale Insight into the Relation between Pressure Solution of Calcite and Interfacial Friction

方解石压溶与界面摩擦关系的纳米尺度洞察

DOI：
10.1016/j.jcis.2021.04.145
发表时间：
2021-05
期刊：
Journal of Colloid and Interface Science
影响因子：
9.9
作者：
Fu, Binxin;Diao, Yijue;Espinosa
通讯作者：
Espinosa

Ion specific effects on the pressure solution of calcite single crystals

离子对方解石单晶压溶的特定影响

DOI：
10.1016/j.gca.2020.04.010
发表时间：
2020-07
期刊：
Geochimica et Cosmochimica Acta
影响因子：
5
作者：
Diao, Yijue;Li, Anqi;Espinosa
通讯作者：
Espinosa

Limits to Crystallization Pressure

结晶压力的限制

DOI：
10.1021/acs.langmuir.2c01325
发表时间：
2022-09
期刊：
Langmuir
影响因子：
3.9
作者：
Li, Lei;Kohler, Feli;Dziadkowiec, Joanna;Røyne, Anja;Espinosa Marzal, Rosa M.;Bresme, Fernando;Jettestuen, Espen;Dysthe, Dag Kristian
通讯作者：
Dysthe, Dag Kristian

Velocity-weakening and -strengthening friction at single and multiasperity contacts with calcite single crystals

方解石单晶单凹凸体和多凹凸体接触处的速度减弱和增强摩擦