Nano- to microscale wear and mechanical characterization using scanning probe microscopy

Abstract

Scanning probe microscopy (SPM) techniques, specifically so-called atomic force/friction force microscopy (AFM/FFM) are increasingly used for tribological studies of engineering surfaces at scales ranging from atomic and molecular to microscales. AFMs with suitable tips are being used to study microscratching, microwear and nanowear and nano/picoindentation behavior of solid surfaces and thin films. AFMs have also been used for nanofabrication/nanomachining purposes. Scratch and wear properties of a variety of materials have been measured. Mechanisms of material removal on the microscale are studied. Wear precursors can be detected at early stages of wear using localized surface potential measurements. Localized surface elasticity maps of composite materials with penetration depths of less than 100 nm can be obtained. Nanoindentation hardness and Young’s modulus of elasticity can be measured with a depth of indentation as low as 1 nm. Scratching and indentation on the nanoscale are powerful ways to screen for adhesion and resistance to deformation of ultrathin coatings. These studies provide insight into failure mechanisms of materials and thin coatings. Finally, in situ surface characterization of local deformation of materials and thin coatings helps to develop better understanding of failure mechanisms.