Use of Nano-Indentation and Nano-Scratch Techniques to Investigate Near Surface Material Properties Associated With Scuffing of Engineering Surfaces

摘要

Scuffing is a very complex process, without a clear understanding of the fundamental causes behind itsoccurrence. It is clear that there are many factors that affect this process, but it is only through obtaining an in-depthunderstanding of the actual conditions (i.e. chemical, topographical, mechanical, and microstructural analyses), thata fundamental cause can be determined. Most prior research has focused on examination of subsurface changes atthe micron level. Recent findings suggest that the most significant changes occur in the top 50 ??? 100 nm of thesurface, not at the micron level as previously suggested. The goal of this project is to substantiate this claim that themost significant changes occur in the top 50 ??? 100 nm, and to quantify the changes in material properties at thislevel. Microstructural analysis and nano-mechanical methods of determining thin film material properties are usedto accomplish these goals.The nano-mechanical methods that will be used in this work are nano-indentation and nano-scratchtechniques. These methods are routinely used in such applications as semi-conductors and magnetic storage harddisk drives. Applying these methods to engineering surfaces is anticipated to be somewhat difficult (and thus, thelack of published works in this area), due to significant roughness, non-homogeneous surfaces and inconsistentlayers of unknown and non-uniform thicknesses. Through careful examination and analysis of individual data, it isshown that these methods can in fact be applied to engineering surfaces.