Self-lubricating nanoscaled metal matrix composites

摩擦磨损是机械零件受相对运动时普遍存在的现象。机械系统的日益复杂及其日益苛刻的运行环境需要新的工程解决方案，以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运行过程中环境条件的严格限制，导致它们主要部署在室温或接近室温的应用中，以减少它们的退化。此外，流体润滑剂的另一个挑战是在运行过程中进行补充，有时会导致维护停止，从而影响平稳运行。这些缺点的一个替代方案是在自润滑系统中使用固体润滑剂，因为它以一种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进行了探索，但仍然有许多悬而未决的问题，这些问题对于它们的广泛应用至关重要。第一个是关于最适合的润滑机制的类型。目前的固体润滑剂主要有两种不同的润滑方式。在层状润滑剂中，机理是基于界面剪切，而在纤维状润滑剂中，机理是滚动和滑动的混合。第二个悬而未决的问题与润滑剂与所含技术金属的整合有关。在这种情况下，必须为每个特定的体系探索两个相之间的化学反应和物理反应。最后，第三个主要问题在于是否有可能找到一种“全能”，它可能能够在最多样化和极端的条件下运行，而不会显著退化并保持所需的润滑性。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，对自润滑复合材料进行首次完整和彻底的分析。所选择的基质材料是镍基高温合金，这种合金在极端环境中找到了应用的利基，例如涡轮叶片。作为固体润滑剂，将测试传统的层状材料(石墨、MoS2和WS2)，并与缺乏前者常见操作限制的新型固体润滑剂(碳纳米管和石墨烯)进行对比。制造后，复合材料将在不同环境(温度和湿度)下滑动之前和之后进行广泛的表征。该项目的主要目标是获得一种可以在多种条件下发挥作用的自润滑复合材料。该项目的研究团队由奥地利科学院埃里希·施密德研究所的Andrea Bachmaier博士和UniSaarland的功能材料主席Sebastian Suarez博士组成

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