Surface Chemical Effects on the Mechancial Properties of Solids: Combined Experimental and Large Scale Massively Parallel Atomic Level Simulations

9900278 Corcoran这个研究项目的目标是量化特定电化学环境下金属表面纳米级机械性能的变化，在这种环境中，表面能量、表面应力、化学成分和多余的表面电荷可以得到精确的控制。具体地说，将在金属表面上进行原位纳米压痕测量(硬度、弹性模数、附着力和压痕蠕变)，其结果是(1)通过电化学控制表面电荷来系统地改变表面应力，(2)通过电化学沉积应变金属单层以及表面氧化物的生长来改变表面能量和应力，以及(3)通过使用不同的探头-样品组合来改变表面和表面探针之间的附着力。这些结果将有助于更好地理解表面化学改变表面纳米机械性能的基本机制。这些结果有望对润滑剂的开发和对摩擦过程的基本理解产生影响。***

9900278CorcoranThe objective of this research project is to quantify the changes in nanoscale mechanical properties of metal surfaces under specific electrochemical environments where the surface energy, surface stress, chemical composition and excess surface charge can be precisely controlled. Specifically, in-situ nanoindentation measurements (hardness, elastic modulus, adhesion and indentation creep) will be performed on metallic surfaces as a function of (1) systematically varying the surface stress through electrochemical control of the surface charge, (2) varying the surface energy and stress through the electrochemical deposition of strained metal monolayers as well as the growth of surface oxides, and (3) varying the adhesion between the surface and the surface probe through the use of different probe-sample combinations. These results will lead to a better understanding of the basic mechanisms by which surface chemistry can alter the nanomechanical properties of surfaces. These results are expected to have implications in lubricant development and a basic understanding of friction processes. ***