Electrical behaviors of plasma-sprayed Al2O3-TiO2 coatings have been investigated in terms of their TiO2 content. On increasing the TiO2 content from 6 to 30 wt%, the DC electrical conductivity increased by several orders of magnitude. From impedance spectroscopy analysis, the total conductivity of the grains and grain boundaries and their respective activation energies were determined without the electrode effects that could impede ionic transfer. An electron transference number was also estimated, ranging between 6.5% and 7.3% for 13 wt% TiO2 and between 0.4% and 0.7% for 30 wt% TiO2 in the coating. Because of the high electronic contribution to the total conductivity, the Al2O3-TiO2 coating could be a new candidate material to obtain superior electrical conductivity as well as corrosion and wear resistances.
