Atomic Wear

原子磨损

基本信息

批准号：
351709183
负责人：
Professor Dr. André Schirmeisen
金额：
--
依托单位：
Institut für Angewandte Physik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/351709183?language=en
关键词：
Atomic Wear

项目摘要

The wear of mechanical components like bearings or gears limits the life time of machines and results in increased costs of operation and raw materials as well as down times of factories. Avoiding wear and abrasion in various applications is of enormous economical as well as ecological interest. The classic theory of surface wear distinguishes between adhesive and abrasive wear. The former describes the detachment of parts of the surface, while the latter process is characterized by the plowing of the softer surface by the asperities of the harder counter surface. A general microscopic understanding of the underlying atomic wear processes does not exist. A useful approach for the analysis of those processes is to analyze the wear of individual asperities. In particular the atomic force microscope has proven to be a valuable tool, since its geometry closely resembles the ideal single asperity contact.New wear models have in recent years been motivated by experimental results from friction force microscopy studies. The atomic wear for nanoscale contacts has extremely low values of only one atom per millimeter sliding distance. As a consequence recent approaches to describe the process model it as the detachment of individual atoms from the surface, where the rate of overcoming the energy barrier is modelled with the rate equation. Despite the first successful applications of the rate theory, it is only one of several possible descriptions.The key experiment to verify the rate model for atomic wear would be the systematic measurement of the wear of nanoscale contacts as a function of temperature. Such an experimental has not been conducted so far, and is the main focus of this proposal. One central question is: Up to which temperatures is atomic wear dominated by thermal activation? At very low temperatures one would expect a transition to athermal wear, obeying the principles of mechano-chemistry, i.e. the formation/breaking of chemical bonds by force interactions. The measurements will be conducted with three model material systems, to focus on different aspects of atomic wear. Using a friction force microscope in ultrahigh vacuum conditions the atomic wear mechanisms will be studied on ionic crystals, polymers as well as diamond surfaces. For the direct verification of the rate model the wear will be quantified as a function of sample temperature. A sample cooling/heating stage allows assessing a large temperature range from 30 K to 700 K. Our central project goal is to find and understand the anticipated transition from thermal activated to athermal atomic wear processes.

机械组件（例如轴承或齿轮）的磨损限制了机器的寿命，并导致操作和原材料成本增加以及工厂的停机时间。在各种应用中避免磨损和磨损具有巨大的经济性和生态兴趣。表面磨损的经典理论区分了粘合剂和磨料磨损。前者描述了表面部分的脱离，而后一个过程的特征是较柔和的表面耕作，而较硬的柜台表面的凹陷。对潜在的原子磨损过程的一般微观理解不存在。分析这些过程的一种有用的方法是分析个体悬垂性的磨损。特别是，原子力显微镜已被证明是一种有价值的工具，因为它的几何形状与理想的单肌接触非常相似。近年来，新的磨损模型是由摩擦力显微镜研究的实验结果激励的。纳米级触点的原子磨损极低的值仅为每毫米滑动距离一个原子。结果，将过程模型描述为从表面脱离的过程模型的最新方法，其中克服能量屏障的速率是用速率方程式建模的。尽管速率理论的首次成功应用，但它只是几个可能的描述之一。验证原子磨损速率模型的关键实验将是对纳米级接触的磨损的系统测量。到目前为止，此类实验尚未进行，并且是该提案的主要重点。一个中心问题是：在哪种温度以热激活为主的原子磨损？在非常低的温度下，人们会期望过渡到易磨损，遵守机械化学原理，即通过力相互作用对化学键的形成/破裂。测量将使用三个模型材料系统进行，以关注原子磨损的不同方面。在超高真空条件下，使用摩擦力显微镜将原子磨损机制研究在离子晶体，聚合物和钻石表面上。为了直接验证速率模型，将磨损作为样品温度的函数。样品冷却/加热阶段允许评估30 K到700 K的较大温度范围。我们的中心项目目标是找到并了解从被激活的热量到静脉原子磨损过程的预期过渡。