Microstructure, mechanical properties and tribological behavior of Cu-nano TiO2-MWCNTs composite sintered materials

The paper presents the results of microstructure, mechanical and tribological tests of copper matrix sinters with the addition of nano-TiO2 and copper-decorated multi-walled carbon nanotubes. A powder metallurgy was used for the production of composite materials. The aim of the work was to determine the properties and wear mechanism of the produced sinters with single additives and to investigate the synergistic interaction of titanium dioxide and carbon nanotubes. Wear tests were carried out using the pin-on-disc method at room temperature and 600 degrees C. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Raman Microscopy, Thermogravimetric Analysis (TGA), Dilatometry (DIL), X-Ray Diffrac-tion (XRD), and profilometer were used for the research. Moreover, the stiffness and hardness of the sinters were examined. The main wear mechanisms of the friction pairs tested at room temperature and 600 degrees C were adhesive, abrasive, and oxidation wear. Furthermore, at the test temperature of 600 degrees C, the formation of a tribofilm was observed on the surface of the friction pairs, which reduced friction wear. The introduced additions to the copper matrix increased its hardness, stiffness, work of axial deformation, and wear resistance. Moreover, additions decreased the relative value of the thermal expansion coefficient of the sintered copper. The friction pair no. 2 (Cu + 1 wt % MWCNTs - Inconel (R) 625) was characterized by the lowest coefficient of friction at room tem-perature and 600 degrees C, of approximately 0.62 and 0.56, respectively. The sintered composite material of Cu - 10 wt % nano TiO2 - 1 wt%. MWCNTs was characterized by the highest mechanical properties and the lowest wear.

Automated summary

This paper investigates the properties and wear mechanism of copper matrix sinters with the addition of nano-TiO2 and copper-decorated multi-walled carbon nanotubes. The study examines the synergistic interaction between titanium dioxide and carbon nanotubes and analyzes the wear mechanisms of the sinters at different temperatures. The results show that the introduced additions improve the hardness, stiffness, work of axial deformation, and wear resistance of the copper matrix.