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6584 |
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High temperature behavior of layered thermal barrier coatings deposited by hybrid water-stabilized plasma |
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Radek Musalek / Institute of Plasma Physics of the Czech Academy of Sciences, Czech Republic Tomas Tesar / Institute of Plasma Physics CAS, Czechia Jan Medricky/ Institute of Plasma Physics CAS, Czechia Frantisek Lukac/ Institute of Plasma Physics CAS, Czechia Rogerio Lima/ National Research Council of Canada, Canada |
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Hybrid water-stabilized plasma (WSP-H) torch may be used for efficient deposition of multiphase coatings from various feedstocks. In this study, WSP-H torch was used to deposit experimental thermal barrier coating with layered top coat. NiCrAlY was used as bond coat and was deposited on nickel-based superalloy. Top coat consisted of three sublayers: i) yttria-stabilized zirconia (YSZ) deposited from solution, ii) gadolinium zirconate (GZO) deposited from suspension, and iii) optional yttrium aluminum garnet (YAG) overlayer deposited from suspension. Each of the sublayers was intended to provide different functionality, namely improved fracture toughness, low thermal conductivity and erosion resistance, respectively. High temperature capability of the deposited coating was tested by isothermal annealing, thermal cycling fatigue test and laser-rig test, exposing samples to isothermal and gradient thermal conditions, respectively. Failure analysis enabled identification of the dominant failure mechanisms for each of the different loading modes. |