Micromechanical Properties of Nanometer-Thick Layers of Implanted Alumina

Abstract

In the presented work we examined two methods of friction reduction of alumina samples; (i) formation of thin surface layer of reduced hardness (to take advantage of Tabor and Bowden concept of adhesive friction in layered materials) and (ii) introduction of nanometer-sized precipitates of solid lubricants to the surface layer of material. The samples were implanted with various doses of inert ions (Ar) or with soft metal ions (In). Both methods lead to significant friction reduction, the best results being obtained for alumina implanted with In ions when the friction coefficient was reduced more than three times. The measurements of nanohardness revealed substantially lower hardness of the irradiated layers. The sample surface was inspected by Scanning Electron Microscopy (SEM) technique supplemented with the elemental analysis. The results obtained are discussed taking into account the level of radiation damage caused by ion implantation and the presence of impurity atoms. The analysis of the experimental data allowed us to explain the obtained results within the frames of the adhesive friction theory.