Development of ceramic coatingsin the Cr2O3-TiO2 system
Dr.-Ing. Lutz-Michael Berger, Dipl.-Min. Sabine Saaro, Dipl.-Ing. Carl Christoph Stahr, Dipl.-Min. Sven Thiele, Dr. Mathias Woydt
In the present work the preparation and properties of APS- and HVOF-spraye coatings from all regions of the Cr2O3-TiO2 phase diagram were systematically investigated for the first time. For the preparation of experimental feedstock powders on the TiO2-rich side and for the interpretation of the phase compositions of the coatings the Cr2O3-TiO2 phase diagram was analysed in detail. Apart from commercially available feedstock powders on the Cr2O3-rich side, five agglomerated and sintered experimental powders on the TiO2-rich side were used. The desired phase compositions could be obtained in these experimental powders. Both spray processes produced homogeneous and lowporosity coatings. Considerable changes in the phase compositions occurred as a result of the spray processes. For coating hardness, electrical resistivity and resistance in dry sliding wear a dependence of the properties on Cr2O3 content was found. The low resistivity on the TiO2-rich side was found as expected. The coatings have great potential for application as ceramic coatings with excellent high-temperature stability and electrical conductivity.
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