Self-lubricating nanoscaled metal matrix composites

摩擦和磨损是相对运动的机械零件中普遍存在的现象。机械系统的复杂性日益增加，操作环境要求越来越高，需要新的工程解决方案来确保其正常运行和延长使用寿命。几十年来，减少摩擦和磨损的常用方法一直是使用流体润滑剂。然而，它们的应用一直受到操作期间的环境条件的严格限制，导致它们主要在室温或接近室温的应用中部署，以减少它们的降解。此外，流体润滑剂的另一个挑战是在操作期间的补充，有时会导致影响平稳操作的维护停止。这些缺点的替代方案是在自润滑系统中使用固体润滑剂，因为它以直接的方式克服了最关键的问题。这种方法，虽然已经在文献中探讨，仍然有一个广泛的开放的问题，是其广泛应用的关键。第一个问题涉及最合适的润滑机制类型。目前的固体润滑剂主要有两种润滑方式，这两种润滑方式有着严格的区别。在层状润滑剂中，该机制是基于界面剪切，而在纤维状润滑剂中，该机制是滚动和滑动的混合。第二个未决问题涉及润滑剂与所含技术金属的结合。在这种情况下，必须针对每个特定系统探索两相之间的化学和物理反应性。最后，第三个主要问题是能否找到一个“多面手”，能够在最多样化和极端的条件下运作，该项目旨在通过结合创新的制造技术，（高压扭转）和先进的微观结构和化学表征技术。所选择的基体材料是镍基超合金，其在极端环境中找到了它们的应用领域，例如涡轮机叶片。作为固体润滑剂，将测试传统的层状材料（石墨，MoS2和WS2），并与新型固体润滑剂（碳纳米管和石墨烯）进行对比，后者缺乏在前者中观察到的通常操作限制。制造完成后，复合材料将在不同环境（温度和湿度）下经受滑动条件之前和之后进行广泛表征。该项目的主要目标是获得一种可在广泛条件下发挥作用的自润滑复合材料。该项目的研究团队由Andrea Bachmaier博士（奥地利科学院Erich Schmid研究所）和塞巴斯蒂安苏亚雷斯博士（UniSaarland功能材料主席

Friction and wear are ubiquitous phenomena in mechanical components subjected to relative motion. The increasing complexity of mechanical systems and their progressively demanding operational environments require new engineering solutions for their proper functioning and extended duty life. The usual approach to reduce friction and wear has been for decades the use of fluid lubricants. However, their application has been always severely restricted by the environmental conditions during operation, resulting mainly in their deployment in applications at, or near room temperature, so as to diminish their degradation. Furthermore, another challenge of fluid lubricants is the replenishment during operation, resulting sometimes in maintenance stops that affect the smooth operation. An alternative to these drawbacks is the use of solid lubricants in self-lubricating systems, since it overcomes the most critical issues in a straightforward way. This approach, though already explored in the literature, still has a wide span of open questions that are critical for their extensive application. The first concerns the type of lubrication mechanism that is most suitable. Current solid lubricants present two main lubrication modes, being strictly different from each other. In layered lubricants, the mechanism is based on the interfacial shear and in fibre-like lubricants, the mechanism is a mix of rolling and gliding. The second open question is related to the integration of the lubricant to the containing technical metal. In this case, chemical and physical reactivity between both phases has to be explored for each particular system. Finally, the third main question lays on the possibility of finding an “all-rounder”, which might be able to operate in the most diverse and extreme conditions, without being significantly degraded and maintaining the required lubricity.This project aims at providing a first integral and thorough analysis of self-lubricating composites by combining an innovative manufacturing technology (high pressure torsion) and advanced microstructural and chemical characterization techniques. The chosen matrix materials are Ni-based superalloys, which find their application niche in extreme environments like, for example, turbine blades. As solid lubricants, traditional layered materials will be tested (graphite, MoS2 and WS2) and contrasted to novel solid lubricants (carbon nanotubes and graphene) that lack the usual operational limits observed in the former. After manufacturing, the composites will be extensively characterized before and after being subjected to sliding conditions in diverse environments (temperature and humidity). The main objective of the project is to obtain a self-lubricating composite that may function in a broad set of conditions. The research team of the project consists of Dr. Andrea Bachmaier (Erich Schmid Institute, Austrian Academy of Sciences) and Dr. Sebastian Suarez (Chair of Functional Materials, UniSaarland