Structure and Interface Evolution in Self-Lubricating Coatings and Nanocomposites for Moving Mechanical Assemblies

用于移动机械组件的自润滑涂层和纳米复合材料的结构和界面演变

• 批准号: 0700828
• 负责人: Thomas Scharf
• 金额: $ 21万
• 依托单位: University of North Texas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0700828&HistoricalAwards=false
• 关键词: Structure; Interface; Evolution; Self; Lubricating

Moving mechanical assemblies (MMA), such as miniature rolling element bearings, gears and other precision components, must function reliably and predictably in device operation. Advancements in MMA products have required a reduction in the dimensions of these devices, thereby increasing the influence of dynamic tribological surface interactions on performance and reliability. Presently, there are several shortcomings and challenges, including nanoscale conformality and uniformity of coatings on buried surfaces/interfaces, application of new routes to coating synthesis on fully assembled MMA, accurate characterization of complex coating microstructures and tribochemically-modified interfaces under shearing loads, and site-selective deposition of coating on critical tribological surfaces. UNT and Timken propose a two-fold research strategy to address these issues. First, novel coating synthesis techniques will be developed utilizing atomic layer deposition (ALD), with the goal of depositing nanocomposite and nanolaminate solid lubricants, especially lubricious oxides and metal nitrides/sulphides, on fully assembled MMA devices. In addition, the fundamental structure and properties of nanocomposite tribological films deposited with plasma-discharge vapor deposition systems will be examined, including films containing nanoscale metal carbides in mixed sp3/sp2 carbon matrices. Second, the research will address the composition/structure dependence of tribological thin films on performance and explore the mechanisms of film modification by tribo-chemical reactions in MMA applications. Desired outcomes include correlations of film initial nanostructure and properties to macro-scale friction and wear performance, increasing scientific understanding of these phenomena and supporting the development of predictive models. To accomplish these goals, new diagnostic tools and methods at UNT will be utilized to study interfacial composition, periodicity, and morphological changes occurring at the surface and in the subsurface regions, as well as tribochemical reactivity under varying contact stress and environments with focused ion beam cross-sectional SEM, analytical high resolution TEM, and local electrode 3-D atom probe (LEAP) tomography.This proposal will address educational activities with integration of Materials Science and Engineering between UNT and Timken. During the tenure of this program, one undergraduate and one graduate student will be provided a thorough background in the processing, structure and property interrelationships of tribological coatings applicable to current surface engineering issues. This will provide the students the opportunity to externally collaborate on issues critical to future industry needs. A number of the PI's current and future students include minorities and women, and they will participate in the collaborative external interaction. This cooperative venture will help bridge the gap in transferring technology from research to commercial application. Outreach programs to local K-12 levels will also be implemented in the summer with educational and hands-on 'Materials Camp' programs.

移动机械组件（MMA），如微型滚动轴承、齿轮和其他精密部件，必须在设备运行中可靠且可预测地运行。 MMA产品的进步需要减小这些装置的尺寸，从而增加动态摩擦表面相互作用对性能和可靠性的影响。 目前，有几个缺点和挑战，包括纳米级的保形性和均匀性的涂层上埋的表面/接口，应用新的路线完全组装的MMA上的涂层合成，精确表征复杂的涂层微观结构和摩擦化学改性界面下的剪切载荷，和位点选择性沉积的涂层上的关键摩擦表面。 UNT和铁姆肯公司提出了一个双重研究策略来解决这些问题。 首先，将利用原子层沉积（ALD）开发新型涂层合成技术，目标是在完全组装的MMA设备上沉积纳米复合材料和纳米层压固体润滑剂，特别是润滑氧化物和金属氮化物/硫化物。 此外，将检查与等离子体放电气相沉积系统沉积的纳米复合材料摩擦膜的基本结构和性能，包括在混合sp3/sp2碳基质中含有纳米级金属碳化物的膜。 其次，研究将解决摩擦学薄膜的组成/结构对性能的依赖性，并探索在MMA应用中通过摩擦化学反应进行膜改性的机制。 期望的结果包括膜初始纳米结构和性质与宏观尺度摩擦和磨损性能的相关性，增加对这些现象的科学理解并支持预测模型的开发。 为了实现这些目标，UNT将利用新的诊断工具和方法来研究表面和次表面区域发生的界面组成、周期性和形态变化，以及在不同接触应力和环境下的摩擦化学反应，使用聚焦离子束横截面SEM、分析高分辨率TEM、和局部电极三维原子探针（LEAP）断层扫描。该提案将涉及联合NT和铁姆肯公司之间材料科学与工程整合的教育活动。 在该计划的任期内，一名本科生和一名研究生将提供适用于当前表面工程问题的摩擦涂层的加工，结构和性能相互关系的全面背景。 这将为学生提供机会，就未来行业需求的关键问题进行外部合作。 一些PI的当前和未来的学生包括少数民族和妇女，他们将参与合作的外部互动。 这一合作企业将有助于弥合技术从研究向商业应用转移的差距。 对当地K-12水平的推广计划也将在夏季实施教育和实践“材料营”计划。