Abstract

Reactivity of nanosized objects is a hot topic in modern solid-state chemistry and materials science. The present work is focused on the interaction between multi-walled carbon nanotubes (MWCNTs) and metallic titanium during high-energy ball milling and thermal explosion, a rapid temperature rise in a mixture caused by an exothermic reaction ignited by external heating and occurring throughout the sample volume. A fundamental property of the nanocomposite mixture—the ability of its components to react in the combustion mode—is explained; an analysis of the dependence of the combustion characteristics of the nanocomposites on the milling duration of powder mixtures is provided. The phase and structural transformations of the Ti-MWCNT mixtures have been analyzed using X-ray diffraction and transmission electron microscopy. It was found that the ball-milled powders contain nanostructured titanium, nanotube fragments, amorphous carbon and nanosized carbon-deficient titanium carbide TiCx. Within the nanocomposite powder particles, TiCx nanoparticles are covered with layers of amorphous carbon. Thermal explosion was observed in Ti-4mass%MWCNT mixtures milled for 1.5–7 min. Shorter milling times were apparently not sufficient for establishing a proper interfacial contact, while longer milling times led to the extensive formation of titanium carbide TiCx, which acted as a barrier lowering the heat release by the mixture upon ignition. Both the ignition temperature of Ti-4mass%MWCNT and the maximum temperature developed during thermal explosion decrease with the milling time. A comparison of the behavior of MWCNT with that of carbon black under conditions of thermal explosion in the mixtures with titanium is also presented.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call