Friction and Contact Ageing on Metal Surfaces

• Applicant: Professor Dr. Roland Bennewitz
• Subject Area: Mechanical Properties of Metallic Materials and their Microstructural Origins ; Experimental Condensed Matter Physics
• Term: from 2013 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 239754128

Friction on metal surfaces is a phenomenon of broadest technical relevance, examples include machining or moving electrical contacts. Friction between metals in contact originates in the formation and shearing of a multitude of microscopic contacts. In this experimental project we develop an understanding of the processes which determine friction of microscopic metallic contacts. Friction force microscopy allows us to measure forces with atomic-scale resolution and thus provides important insight into the relevant atomic glide planes, plastic deformation processes, and energy dissipation. Recent results indicate that neither an engineering model based on bulk deformation properties nor an atomistic model based on interfacial interactions are sufficient to describe the microscopic phenomena of contact formation, ageing, and sliding. By studying the effects of surface diffusion, of the crystallographic orientation, and of surface passivation by molecular films on friction for different metal surfaces we want to contribute to a predictive model for friction between metals in contact, both for the design of micromechanical systems and as input for an understanding of macroscopic friction phenomena.

• DFG Programme: Research Grants