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3779 |
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Thursday, May 22, 2014, Hall H3 2:40 PM Cold Gas Spraying 3 |
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Interface characterization and bonding mechanisms of cold gas sprayed Al coatings on ceramic substrates |
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Rico Drehmann* / Chemnitz University of Technology, Germany Thomas Grund / Institute of Materials Science and Engineering (IWW), Chemnitz University of Technology, Germany Thomas Lampke/ Institute of Materials Science and Engineering (IWW), Chemnitz University of Technology, Germany Bernhard Wielage/ Institute of Materials Science and Engineering (IWW), Chemnitz University of Technology, Germany Kevin Manygoats/ Institute of Materials Science (IWW), Freiberg University of Technology and Mining, Germany Torsten Schucknecht/ Institute of Materials Science (IWW), Freiberg University of Technology and Mining, Germany David Rafaja/ Institute of Materials Science (IWW), Freiberg University of Technology and Mining, Germany |
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The aim of the present work is to contribute to the understanding of the adhesion mechanisms which take effect at the interface of cold gas sprayed metallic coatings on ceramic substrates. Former investigations revealed that it is possible to deposit well-adhering metallic coatings on atomically smooth ceramics, leading to the conclusion that mechanical interlocking is not always a necessary precondition for bonding. A combination of recrystallisation processes induced by adiabatic shear processes and heteroepitaxial growth might be an explanation for the high observed adhesion strengths. In order to verify this assumption, the present work focuses on the examination of the interface area of cold gas sprayed aluminum on various ceramic substrates by means of scanning electron and high resolution transmission electron microscopy. Besides sintered corundum plates, coatings were applied on monocrystalline sapphire substrates with different lattice orientations. In addition to Al2O3, aluminum coatings were also deposited on AlN, Si3N4, SiC and MgF2 in order to investigate if the differing portions of ionic bonding in these substrate materials do have an influence on interface formation. Furthermore, cold gas sprayed coatings were compared to coatings produced by means of physical vapour deposition. |