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1217 |
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Wednesday, June 04, 2008, Room 04 3:40 PM Nanomaterials 2 Most coating materials gain superior coating performance when applied as nanostructured coating, new designed materials and optimized processes show promising results for this |
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Influence of the HVOF gas composition on the thermal spraying of WC-Co submicron powders (- 8 + 1 µm) to produce superfine structures hard material coatings
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Wolfgang Tillmann* / Institute of Materials Engineering, Germany Evelina Vogli / Institute of Materials Engineering, University of Dortmund, Faculty of Mechanical Engineering, Germany Ingor Baumann/ Institute of Materials Engineering, University of Dortmund, Faculty of Mechanical Engineering, Germany Goetz Matthäus/ Thermico GmbH and Co. KG, Germany Timo Ostrowski/ Thermico GmbH and Co. KG, Germany |
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Thermally sprayed hard material coatings offer a practical, economical solution to protect tool surfaces in various industrial applications against wear and fretting, material adhesions or tribochemical corrosion. In recent years, however, there is an increasing demand for coatings with improved durability and performance. Beside enhanced physical and mechanical properties of the coating material a major focus is placed on high contour profile accuracy and improved surface quality even at a high geometrical complexity of the substrate material. Due to an inappropriate roughness profile or surface deviations caused by irregular layer thicknesses this aim could not be accomplished by currently applied coatings and engineering materials with conventional (coarse-grained) microstructure. A subsequent surface finishing, for example by grinding, is often necessary to obtain a smooth and near-net-shape surface. This collaborative research work between the Institute of Materials Engineering at the University of Dortmund (Germany) and Thermico GmbH & Co. KG, Dortmund (Germany) aims at the development of new thermally sprayed wear resistant surfaces based on superfine- and nanostructured hard material coatings with enhanced functional and structural (tailor-made) properties by employing finest powder fractions. For the powder feeding and thermal spraying process (HVOF) special equipment designed by Thermico has been employed and further optimized to achieve a high density and high adhesion of the coatings on the substrate material. Novel 3D-offline programming software has been developed and applied in the coating process to manufacture near-net-shape coatings. Correlations related to the thermal spraying of finest powder and the coating characteristics have been established. |