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3840 |
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Deposition mechanisms of Al2O3 coatings in suspension plasma spraying (SPS) and high velocity suspension flame spraying (HVSFS) |
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Giovanni Bolelli* / Department of Engineering "Enzo Ferrari", University of Modena and Reggio Emilia, Italy Vincenzo Barbaro / Dipartimento di Ingegneria Enzo Ferrari , University of Modena and Reggio Emilia, Italy Valeria Cannillo/ Dipartimento di Ingegneria Enzo Ferrari , University of Modena and Reggio Emilia, Italy Rainer Gadow/ Institute for Manufacturing Technologies of Ceramic Components and Composites (IMTCCC), Germany Andreas Killinger/ Institute for Manufacturing Technologies of Ceramic Components and Composites (IMTCCC), Germany Luca Lusvarghi/ Dipartimento di Ingegneria Enzo Ferrari , University of Modena and Reggio Emilia, Italy Philipp Müller/ Institute for Manufacturing Technologies of Ceramic Components and Composites (IMTCCC), Germany |
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Suspension thermal spray processes hold significant promise for the deposition of finely structured ceramic oxide coatings, as they enable the processing of very fine feedstock powders (micrometric, sub-micrometric or even nanometric), resulting in smaller splat size than conventional processes. Suspension plasma spraying (SPS) and high velocity suspension flame spraying (HVSFS) are two of the most important emerging technologies in the field of suspension spraying. The characteristics of these processes differ significantly. The present work therefore aims to perform a comparative investigation on the deposition mechanisms of ceramic oxide coatings in the SPS and HVSFS processes, using a well known and industrially widespread material, Al2O3, as a case study. Different feedstock powders having micrometric and submicrometric particle size were dispersed in various liquid media (including water, isopropanol and a 50/50 mixture of them) and sprayed by HVSFS and SPS. The characteristics of molten particles produced in-flight were investigated by collecting them in water. The morphology of the resulting single splats were studied by depositing them onto smooth glass and steel surfaces. The microstructure and micromechanical properties of corresponding complete coatings, sprayed onto stainless steel plates, were characterised by SEM, XRD and micro-indentation techniques. |