Characterization of interfaces in ZrO2–carbon nanofiber composite

Zirconia–carbon nanofiber (CNF) composite was prepared with the aim of improving the electrical conductivity of the zirconia. Transmission electron microscopy was used to characterize the interfaces in the composite and to explain the significantly improved conductivity compared with monolithic zirconia. Three different interfaces have been found: clear ZrO2/ZrO2 boundaries, ZrO2/ZrO2 boundaries with CNF and ZrO2/ZrO2 boundaries with disordered graphite (which results from the destruction of CNFs during processing). The modified grain boundaries together with the presence of CNFs are the reason for the improved conductivity.