Microstructure and mechanical properties of plasma sprayed alumina-based coatings

TitleMicrostructure and mechanical properties of plasma sprayed alumina-based coatings
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2014
AuthorsDi Girolamo, G., Brentari A., Blasi C., and Serra Emanuele
JournalCeramics International
KeywordsAfter-heat treatment, Alumina, Alumina-titania coatings, Aluminum, Aluminum coatings, Atmospheric plasma spraying, Coatings, Energy dispersive spectroscopies (EDS), Energy dispersive spectroscopy, High temperature, Industrial applications, Mechanical properties, Metastable phases, Microstructure, Microstructure and mechanical properties, Plasma jets, Plasma spraying, Porous microstructure, Powder coatings, Powder particles, Scanning electron microscopy, Titanium dioxide, X ray diffraction

Alumina-based coatings are employed in many industrial applications, in order to protect the surface of metal components against high temperature, wear, corrosion and erosion. In this work two different alumina-based coatings were fabricated by atmospheric plasma spraying (APS), starting from powder particles composed of pure Al2O3 and Al2O3-3 wt% TiO2, respectively. Their phase composition was investigated by X-Ray Diffraction (XRD) and revealed that both the as-sprayed coatings were mainly composed of metastable γ- and α-Al2O3 phases. The γ phase recrystallized to α phase after heat treatment. The porous microstructure was analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Thin TiO2-rich splats were observed within the microstructure of alumina-titania coatings. The pure alumina coatings exhibited similar porosity and higher microhardness than the alumina-titania ones (12.8 against 9.9 GPa). Both the coatings herein analyzed are particularly promising for high-temperature anti-wear applications, because of their enhanced mechanical properties. © 2014 Elsevier Ltd and Techna Group S.r.l.


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