Title: Mechanical properties of bi-layer and dispersion coatings composed of several nanostructures

Abstract

For use in biomedical applications the mechanical properties of the composite coatings were evaluated. Six coatings electrophoretically deposited on Ti13Nb13Zr alloy and Ti Grade II substrate were studied: the coating composed of multi-wall carbon nanotubes (MWCNTs),the dispersion coating consisting of MWCNTs and nanocopper and the bi-layer coating comprised of titanium dioxide, electrophoretically deposited on MWCNTs layer. Optic microscopy, scanning electron microscopy, X-ray electron diffraction spectroscopy and nanoindentation were applied to study the chemical and phase composition, roughness, wear resistance, plastic and elastic properties. The best mechanical, plastic, and elastic properties in terms of biomedical application were achieved for the MWCNTs coating with titania layer deposited on Ti Grade II substrate, while the coating composed of MWCNTs and copper turned out to be more brittle when deposited on Ti alloy than on Ti grade II. Generally, both the addition of nanocopper and titania improved the mechanical properties of the base MWCNTs coating deposited on Ti grade II, but for Ti alloy, which served as a substrate for MWCNTs coatings the additions just improved the capability of the MWCNTs coating to accommodate substrate deflection under applied load. This could be explained by the fact that more homogenous coatings generally form on pure metals than on its alloys, which chemical and phase composition is more complex.