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5281 |
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Thursday, June 08, 2017, Hall 27 12:00 PM HVAF Spraying |
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Nanostructural WC-Co coatings by utilizing novel powder manufacturing route using water soluble raw materials |
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Marjaana Karhu* / VTT Technical Research Centre of Finland Ltd., Finland Juha Lagerbom/ VTT Technical Research Centre of Finland Ltd, Finland Kimmo Kaunisto/ VTT Technical Research Centre of Finland Ltd, Finland Tomi Suhonen/ VTT Technical Research Centre of Finland Ltd, Finland Tomi Lindroos/ VTT Technical Research Centre of Finland Ltd, Finland Erja Turunen/ VTT Technical Research Centre of Finland Ltd, Finland |
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Tungsten carbide -based hard metal coatings are extensively used in demanding industrial applications like for wear protection purposes. Continuously increasing demands set new limits and need for materials with enhanced features. One solution is to improve hard metal properties by nanostructures. Presented study is part of a research where novel and safe route to manufacture WC-Co powders starting from water soluble raw materials was developed. In this study powders workability in thermal spray coatings is studied. WC-Co powders were manufactured using water soluble raw materials: ammonium metatungstate as a tungsten source, glycine as a carbon source and cobalt acetate as a cobalt source. Grain growth inhibitors (VC, Cr3C2) were used for controlling grain size of the carbides. The powders were manufactured via optimized spray drying and heat treatment method producing correct phase structure and chemical composition. Experimental powders were sprayed by HVAF-spraying to study their workability and functionality. Morphology, microstructure and properties were analyzed from the produced powders and the HVAF-coatings |