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5726 |
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Friday, June 09, 2017, Hall 26 12:00 PM Corrosion Protection |
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Tribological properties of high velocity suspension flame sprayed (HVSFS) ceramic coatings |
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Andrea Förg* / University of Stuttgart, Germany Andreas Killinger / Institute for Manufacturing Technologies of Ceramic Components and Composites IFKB, University of Stuttgart, Germany Georg Konrath/ Fraunhofer Institute for Mechanics of Materials IWM, Germany Andreas Kailer/ Fraunhofer Institute for Mechanics of Materials IWM, Germany Rainer Gadow/ Institute for Manufacturing Technologies of Ceramic Components and Composites IFKB, University of Stuttgart, Germany |
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State-of-the-art cermet coatings deposited via thermal spraying feature a high hardness and advantageous wear behavior. They are therefore generally applied as protective layers on diverse components working under severe conditions. However, cermets generally consist of materials with limited resources like tungsten or cobalt and potentially harmful metals like nickel. In addition, these coating systems do not offer a reliable protection for applications that are confronted with both wear and corrosion. Alternatively, ceramic materials are considered to provide a substantial resistance against tribocorrosive loads. Ceramic coatings possess good mechanical properties like high hardness and are chemically inert so that they show high resistance against not only tribological but also corrosive attack. Therefore, they represent a sustainable alternative to current cermet systems. The use of finely dispersed suspensions enables the processing of submicron- or nano-scaled powders. Therefore, a more homogeneous microstructure can be obtained which leads to enhanced mechanical and tribological properties comparing with conventional thermal spray coatings. In the frame of this work the investigated ceramic coatings consisting of oxide and carbide systems are deposited via high velocity suspension flame spray (HVSFS). The process allows for creation of dense and finely structured coatings with thicknesses ranging from a few µm up to about 200 µm. The coating development focusses on mixed oxide-carbide HVSFS-coatings with the aim to provide substantial protection against tribocorrosion for media lubricated components like bearings. The microstructural, chemical and mechanical properties of the obtained coatings will be presented as well as the results of tribological lab-scale tests under exposure of corrosive media. |