Friction and plasticity of amorphous metal coatings

该基金的研究目标是阐明非晶态金属涂层中摩擦和塑性的基本机制。 某些MEMS/NEMS器件在动态模式下工作，长期以来一直受到摩擦学问题的困扰。 设备的按比例缩小导致表面力（包括摩擦力）的大幅增加。 在电沉积纳米晶金属制造的微型齿轮中，磨损成为一个重要问题。 与电沉积硬铬涂层相关的环境问题也需要通过环境友好工艺制造相应的替代品。 高强度的非晶态金属涂层是用于这些目的的有吸引力的候选者，因为与金属基底相比，它具有高硬度、低表面粗糙度以及相容的弹性模量和热膨胀系数。 然而，其摩擦行为知之甚少。 非晶涂层的塑性是一个同样重要的课题，因为它直接影响这些涂层的摩擦学性能。 几个假设将被测试，包括非晶金属涂层可能具有比它们的晶体对应物低得多的摩擦系数，层界面可能在非晶多层膜中诱导独特的摩擦和磨损性能。 为了验证这些假设，PI将把非晶薄膜的纳米纤维与先进的摩擦和纳米机械测试技术相结合。如果成功，该项目可能会显着提高NEMS/MEMS组件，磁性数据存储设备和耐磨涂层的可靠性和功能。 该项目衍生的概念和知识将对金属玻璃、涂层、纳米力学、NEMS/MEMS和摩擦学界产生巨大的科学兴趣。 此外，该项目将提供研究培训，研究生和本科生在得克萨斯州A M大学（TAMU）。 将作出特别努力，通过由TAMU资助的“通往博士学位方案”招收女生和其他少数民族学生。 该项目还将通过在引入先进纳米材料时将相关结果纳入课程，并使相对较新的材料科学与工程研究生课程受益，从而增强材料科学和纳米工程课程。 PI将通过NSF-RET计划和参加国际会议，让高中教师参与研究项目，向更广泛的受众传播研究结果。 与国家实验室的合作将为研究生提供暑期研究经验。

The research objective of this grant is to elucidate the fundamental mechanisms of friction and plasticity in amorphous metal coatings. Certain MEMS/NEMS devices operated in dynamic mode have long been haunted by tribological issues. The scale-down of devices leads to large increases in surface force, including friction. In miniaturized gears manufactured by electrodeposited nanocrystalline metal, wear becomes an important issue. Environmental issues associated with electrodeposition of hard Cr coatings also call for commensurate replacement that can be fabricated by environment benign process. High-strength, amorphous metal coating is an appealing candidate for these purposes as it has high hardness, low surface roughness, and compatible elastic modulus and thermal expansion coefficient in comparison to metal substrates. However its friction behavior is poorly understood. Plasticity in amorphous coatings is an equally important subject, as it directly impacts tribological properties of these coatings. Several hypotheses will be tested, including amorphous metal coatings may have much lower friction coefficient than their crystalline counterparts, layer interface may induce unique friction and wear properties in amorphous multilayers. To examine these hypotheses, the PI will combine nanofabrication of amorphous films with advanced friction and nanomechanical testing techniques.If successful, the project may significantly improve the reliability and functionality of NEMS/MEMS components, magnetic data storage devices and wear resistant coatings. The concept and knowledge derived from this project will be of great scientific interest to metallic glass, coatings, nanomechanics, NEMS/MEMS, and the tribology community. Additionally this project will offer research training to graduate and undergraduate students at Texas A & M University (TAMU). Special effort will be made to recruit female and other minority students through the "Pathway to Ph.D program" funded by TAMU. The project will also enhance the materials science and nanoengineering curricula by incorporating the relevant results into classes when introducing advanced nanomaterials and benefit the relatively new Materials Science and Engineering graduate program. The PI will disseminate results to a much broader audience by involving high school teachers in the research project through NSF-RET program and through participation in international conferences. Collaborations with national laboratories will offer graduate students summer research experiences.