Microstructure and Electrical Properties of Coating of the Cr2O3 – TiO2 System

Thermally sprayed coatings from the system TiO₂–Cr₂O₃ are sofar not systematically investigated, but are promising materials for practical applications. On titania-rich side of the phase diagram so called Magneli-phases are formed, which excel by their electrical conductivity. In this paper microstructures and phase compositions of coatings sprayed by APS and HVOF are studied. For preparation of the coatings of chromia-rich compositions commercial powders were used, while for those of the titania-rich side special experimental agglomerated and sintered powders were prepared and used. Pure titania and chromia coatings were studied for comparison. Changes of the phase compositions, induced by the spray processes were studied by X-ray diffraction analyses. Special attention was paid to the measurements of the electrical resistivity of the coatings and its change with composition.