Comparative measurements and analysis of the mechanical and electrical properties of Ti-Zr-C nanocomposite: Role of stoichiometry

Abstract

Nanocomposites based on hard compounds are currently on the stage of active research and development. Hence the analysis of a relation between nanostructure and functional properties are of great importance. The main purpose of the study was to assess the stoichiometry effect on the finite characteristics of TiZrC nanocomposite coatings. This paper presents the analysis of the Ti1-xZrxC (x = 0, 0.25, 0.5, 0.75 and 1.0) hard coatings sputtered onto Si substrates by a two-target DC magnetron. It has been found that the increase of carbon content in the bulk of the coatings contributes to the structural changes, namely, lead to the formation of the nc-Ti1-xZrxCy/a-C nanocomposite structure with (Ti,Zr)C solid-solution phase which is in a good agreement to theoretical predictions. Electrical properties measurements have shown infrequent results concerning intrinsic conductivity, which can prosper this system application for a new generation of nano and microsystems. The analysis reveals the nature of tunnelling conductance between the nanoparticles. On the computer simulation of the frequency dependence of the frequency coefficient, three maxima were discovered. Two of them were attributed to dominant phases (Ti1-xZrx)C and amorphous carbon (a-C). The third one is related to the content of another type of nanophase that, due to low content, could not be determined by structural methods. Mechanical tests showed promising results in suitability to micromechanical devices, in particular: sensors, actuators, power-producing devices. These findings establish an understanding of microstructural regularities and enlarge the potential application space for TiZrC-based systems.