Influence of long-term aqueous exposure on surface properties of plasma-sprayed oxides Cr2O3 and Cr2O3-25 wt% TiO2

The influence of water exposure on the surface properties of plasma-sprayed Cr2O3 and Cr2O3-25 wt% TiO2 was studied. It was shown that both plasma-sprayed materials contained Cr(VI) hydrous oxide phases, which dissolved rapidly at the beginning of water exposure. The dissolution continued slowly during the whole water exposure time. The Cr(VI) dissolution was accompanied by a rapid increase in surface IEP value. Both Cr2O3 and Cr2O3-25 wt% TiO2 showed similar dissolution, zeta potential, and surface oxidation states. Thus the addition of TiO2 did not influence the surface properties of the plasma-sprayed Cr2O3. © 2008 Elsevier Inc. All rights reserved.