High resolution observations of friction-induced oxide and its interaction with the worn surface

• Published in: Tribology international 2002-11, Vol.35 (11), p.731-748
• Main Authors: Rainforth, W.M., Leonard, A.J., Perrin, C., Bedolla-Jacuinde, A., Wang, Y., Jones, H., Luo, Q.
• Format: Article
• Language: English
• Subjects: Nanostructures; Oxidational wear; Transmission electron microscopy
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/S0301-679X(02)00040-3

A detailed transmission electron microscopy study of oxide and oxygen-containing phase formation during the sliding wear of metals, composites and coatings is provided. A wide range of different materials types are reported in order to compare and contrast their oxidational wear behaviour: a low carbon stainless steel, a H21 tool steel containing 7%TiC particles, a 17%Cr white iron, an Al–Si/30%SiC composite, an Al–alloy (6092)–15%Ni 3Al composite and finally a 3rd generation TiAlN/CrN ‘superhard’ multilayer coating. For the ferrous alloys, nanoscale oxides and oxygen-containing phases were formed that exhibited excellent adhesion to the substrate. In all cases, an increase in oxide coverage of the surface was associated with a decrease in Lancaster wear coefficient. The oxide at the surface of the 316L and H21+7%TiC was found to deform with the substrate, forming a mechanically mixed layer that enhanced surface wear resistance. Evidence of oxidational wear is presented for the wear of the Al–Si–30%SiC composite, but this did not give a beneficial effect in wear, a result of the brittle nature of the oxide that resulted in detachment of fine (∼150nm) thick fragments. The worn surface of the Al–alloy (6092)–15%Ni 3Al and TiAlN/CrN coating was characterized by reaction with the counterface and subsequent oxidation, the product of which enhanced wear resistance. The observations are related to the classical theory of oxidational wear.