L. M. Berger, C. C. Stahr, S. Saaro, Fraunhofer Institute for Material and Beam Technology, Dresden, Germany; S. Thiele, Fraunhofer Institute of Ceramic Technologies and Systems (FhG-IKTS), Dresden, Germany
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.
Summary: 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.
