Influence of the multiwall carbon nanotubes on the thermal properties of the Fe-Cu nanocomposites

The relative linear expansion (Delta L/L-0), coefficient of linear thermal expansion (CTE), differential scanning calorimetry (DSC), thermal conductivity and thermopower (E-TP) of the Fe-Cu-MWCNT nanocomposites (Fe:Cu ratio was 4:1; MWCNT = multi-wall carbon nanotubes of 0, 0.5, 1.0 and 2.0 vol% concentration) were measured and analyzed. It was found that MWCNTs effect on thermal behaviour on these nanocomposites varies in different temperature range and the magnitude of the effect depends on the MWCNTs content. The MWCNTs effect on temperature behaviour is mainly realized via blocking the access of copper atoms to iron grains by the MWCNTs atoms. These processes as well as effect of MWCNTs on the condition of the alpha-Fe -> gamma-Fe transformation determine temperature behaviour of the nanocomposites in the range 550-700 degrees C. Insignificant dependence of the relative expansion and coefficient of linear thermal expansion on temperature for the nanocomposites with 2.0 vol% of the MWCNTs indicates perceptiveness of this composition for application, particularly in motor vehicle industry. (C) 2019 Elsevier B.V. All rights reserved.