Influence of the Carbon Allotropes on Dilatometric Properties of the Fe–Cu Nanocomposites

Abstract

AbstractA brief overview of the state-of-art regarding properties of the Fe–Cu composite materials and the impact on them of some forms of carbon is given in the work. Besides, the relative expansion (ΔL/L0), coefficient of linear thermal expansion (CTE), and thermal flow (calorimetric data) were measured for the Fe–Cu-MWCNT composite materials made by mechanical alloying (Fe:Cu ratio was 4:1; MWCNT = multi-wall carbon nanotubes of 0, 0.5, 1.0, and 2.0 vol. % concentration). Effect of the MWCNTs on noted thermal characteristics was discussed using the data on the composition, structure, and morphology of the samples obtained by the X-ray diffraction, Raman spectroscopy, IR absorption, optical and electron microscopy for the study of the noted samples. Several temperature ranges were distinguished for the Fe–Cu-MWCNT composites by the character of the ΔL/L0(T) and CTE temperature dependences. Effect of the MWCNTs on the ΔL/L0 and CTE temperature dependences is different for different temperature ranges, and the magnitude of the effect depends on the MWCNTs content. The mechanisms of temperature and concentration influence were related to the change in composition and structure of composites and they were divided into two groups, such as “oxidation” and “carbidization.” The conclusion was made that carbon atoms of nanotubes play an important role both for “oxidation” and “carbidization” and for their cumulative effect too.