Effect of carbon nanofibers content on thermal properties of ceramic nanocomposites

Abstract

The thermal properties of carbon nanofibers (CNFs)-alumina and CNFs-zirconia nanocomposites densified by spark plasma sintering technique were evaluated. The influence of CNFs content and type of ceramic matrix on thermal conductivity of ceramic-CNFs materials, measured by the laser-flash method, was studied. The effect of CNFs depends noticeably on the ceramic component and thus, an increase of 83% and a decrease of 97% in thermal conductivity at room temperature is observed when 80 vol% of CNFs is added to ZrO2 and Al2O3, respectively. However, even if the thermal conductivity is lower, the efficiency of heat transfer to the environment in CNFs/Al2O3 nanocomposites is better than that corresponding to monolithic alumina. This behavior is due to CNFs arrangement in dense materials. Considering the low electrical resistivity for CNFs/ Al2O3 and CNFs/ ZrO2 materials (10−1–10−2 Ω·cm), these nanocomposites are promising candidates as thermoelectric materials that require low thermal conductivity, but high electrical conductivity.