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3656 |
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Effect of spraying distance on the microstructure and properties of suspension plasma sprayed alumina-based coatings |
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Emilie Bannier / Instituto de Tecnología Cerámica (ITC). Universitat Jaume I (UJI)., Spain Mónica Vicent* / Instituto de Tecnología Cerámica (ITC). Universitat Jaume I (UJI)., Spain Emilio Rayón/ Instituto de Tecnología de Materiales (ITM). Universidad Politécnica de Valencia (UPV), Spain Rut Benavente/ Instituto de Tecnología de Materiales (ITM). Universidad Politécnica de Valencia (UPV), Spain Mª Dolores Salvador/ Instituto de Tecnología de Materiales (ITM). Universidad Politécnica de Valencia (UPV), Spain Enrique Sánchez/ Instituto de Tecnología Cerámica (ITC). Universitat Jaume I (UJI)., Spain |
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Todays industry needs high performance ceramic coatings and nanostructured materials have the potential of providing several industries with novel layers with improved properties and extended lifetime. Such nanostructured coatings can be deposited by plasma spraying using a powder feedstock made of micrometric agglomerates of nanoparticles or a liquid feedstock formed by a suspension of nanometric particles. This last technique method is known as Suspension Plasma Spraying (SPS) and presents the main advantage of simplifying the nanostructured feedstock preparation. Alumina-titania coatings are widely used in industry for wear, abrasion or corrosion protection components. Such layers are commonly deposited by atmospheric plasma spraying (APS), using powder as feedstock. Moreover, nanostructured Al2O3-%TiO2 have been deposited from agglomerated nanostructured powders showing better properties than their conventional counterparts. However, the research on suspension plasma sprayed Al2O3-TiO2 is still incipient and very few studies have been published on such layers. Consequently, it is still necessary to study the effect of the addition of TiO2 on the characteristics of alumina SPS coatings. In this work, Al2O3 and Al2O3-13wt%TiO2 coatings were successfully deposited by suspension plasma spraying from two commercial nanoparticles suspensions (an alumina one and a titania one), using 3 spraying distances. The coatings microstructure and phase composition were characterised using FEG-SEM and XRD techniques. Finally, nanoindentation technique was used to determine the coatings mechanical properties. The influence of the spraying distance on the final coating quality was analysed showing differences in both crystalline phase composition and properties. Shorter spraying distances lead to higher corundum amount in the final coating and thus to better mechanical properties. Moreover, the addition of titania to the initial feed suspension permits a higher melting rate of the initial particles leading to higher mechanical performances. This work has been supported by the Spanish Ministry of Economy and Competitiveness (MAT2012-38364-C03). |