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Improvement of Mechanical Properties of Plasma Sprayed Al2O3–ZrO2–SiO2 Amorphous Coatings by Surface Crystallization

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    0517498 - ÚFP 2020 RIV CH eng J - Journal Article
    Medřický, Jan - Lukáč, František - Csáki, Štefan - Houdková, Š. - Barbosa, M. - Tesař, Tomáš - Čížek, Jan - Mušálek, Radek - Kovařík, O. - Chráska, Tomáš
    Improvement of Mechanical Properties of Plasma Sprayed Al2O3–ZrO2–SiO2 Amorphous Coatings by Surface Crystallization.
    Materials. Roč. 12, č. 19 (2019), č. článku 3232. E-ISSN 1996-1944
    R&D Projects: GA MPO(CZ) FV30058
    Institutional support: RVO:61389021
    Keywords : Amorphous * Nanocrystalline * Plasma spraying * Vickers microhardness * Wear resistant
    OECD category: Materials engineering
    Impact factor: 3.057, year: 2019
    Method of publishing: Open access
    https://www.mdpi.com/1996-1944/12/19/3232

    Ceramic Al2O3-ZrO2-SiO2 coatings with near eutectic composition were plasma sprayed using hybrid water stabilized plasma torch (WSP-H). The as-sprayed coatings possessed fully amorphous microstructure which can be transformed to nanocrystalline by further heat treatment. The amorphous/crystalline content ratio and the crystallite sizes can be controlled by a specific choice of heat treatment conditions, subsequently leading to significant changes in the microstructure and mechanical properties of the coatings, such as hardness or wear resistance. In this study, two advanced methods of surface heat treatment were realized by plasma jet or by high energy laser heating. As opposed to the traditional furnace treatments, inducing homogeneous changes throughout the material, both approaches lead to a formation of gradient microstructure within the coatings, from dominantly amorphous at the substrate-coating interface vicinity to fully nanocrystalline near its surface. The processes can also be applied for large-scale applications and do not induce detrimental changes to the underlying substrate materials. The respective mechanical response was evaluated by measuring coating hardness profile and wear resistance. For some of the heat treatment conditions, an increase in the coating microhardness by factor up to 1.8 was observed, as well as improvement of wear resistance behaviour up to 6.5 times. The phase composition changes were analysed by X-ray diffraction and the microstructure was investigated by scanning electron microscopy.
    Permanent Link: http://hdl.handle.net/11104/0302835

     
     
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