Synthesis and Tribological Behavior of Metal Diboride-Nitride Coatings: Optimizing the Hard and Compliant Response

该奖项的研究目标是开发机械硬度和耐磨性的摩擦学涂层，以使：(A)涂层过程提供高一致性(即，在凹入形状中到处都是均匀的厚度)；(B)涂层在正常运行条件下提供低摩擦和低磨损；以及(C)在高载荷和高温等极端运行条件下，摩擦学性能稳定且可预测。具体地说，利用低温化学气相沉积技术，使用单一来源、无杂质的前驱体如Hf(BH4)4沉积了过渡金属二硼化物HfB2、CrB2和TiB2的涂层。与氮的合金化提供了具有可变弹性柔度的HfBxNy涂层；与铬的合金化用于提高抗氧化能力；以及多层涂层的合成，以调节硬度和弹性响应之间的关系，这将影响摩擦学行为。如果这项研究成功，这项研究的结果将产生重大影响：它将使先进的设备的开发成为可能，这些设备没有润滑剂，在侵略性的操作条件下具有良好的寿命。这些设备包括但不限于节能无油压缩机和基于微电子机械的传感和执行装置。工程专业的研究生和本科生通过参与研究而受益。学生们在桑迪亚国家实验室度过暑假，并与桑迪亚和艾默生环境优化技术公司直接互动。这些成果通过在国内和国际专业会议上发表演讲、在同行评议的顶级科学期刊上发表文章、在大学和工业实验室举办的研讨会以及讨论这项工作和国家科学基金会的关键作用的新闻报道来广泛传播。

The research objective of this award is to develop mechanically hard and wear-resistant tribological coatings such that: (a) the coating process affords high conformality (i.e., uniform thickness everywhere within reentrant shapes); (b) the coating provides low friction, and low wear under normal operating conditions; and (c) the tribological performance is stable and predictable under extreme operating conditions, such as high load and high temperature. Specifically, low-temperature chemical vapor deposition is used to deposit coatings of the transition metal diborides HfB2, CrB2, and TiB2 using single-source, impurity-free precursors such as Hf(BH4)4. Alloying with nitrogen affords HfBxNy coatings that have a variable elastic compliance; alloying with Cr is used to enhance oxidation resistance; and multilayer coatings are synthesized to engineer the relationship between hardness and elastic response, which affects the tribological behavior.If successful, the results of this research will have a significant impact: it will enable the development of advanced devices that are free of lubricants and which have excellent lifetime under aggressive operating conditions. These include, but are not limited to, energy-efficient and oil-free compressors and microelectromechanical-based sensing and actuating devices. Graduate and undergraduate engineering students benefit through involvement in the research. Students spend summer time at Sandia National Laboratories, as well as have direct interaction with both Sandia and Emerson Climate Technologies. The results are broadly disseminated by presentations at domestic and international professional conferences, by publication in upper-tier peer-reviewed scientific journals, by seminars given at university and industrial laboratories, and by news stories that discuss the work as well as the critical role of the National Science Foundation.