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4864 |
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Spraying of aluminum nitride-alumina-yttria mixtures in nitrogen plasma |
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Mohammed Shahien* / National Institute of Advanced Industrial Science and Technology, Japan Motohiro Yamada/ Toyohashi University of Technology, Japan Masahiro Fukumoto/ Toyohashi University of Technology, Japan |
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The high thermal conductivity and chemical stability of aluminum nitride (AlN) has attracted wide attention in a diverse range of electrical and electronic applications. Generally, aluminum nitride can be fabricated in the form of powder, sintered compacts and films. The AlN films are fabricated by vapor techniques like chemical/physical vapor deposition. Such techniques are suitable for thin film deposition due to its low deposition rates limitations. On the other hand, thermal spray is an industrial developed technology for thick coatings deposition, due to it high deposition rates. However, it was impossible to fabricate the AlN coatings directly in the conventional thermal spray techniques. It is due to the AlN particles decomposition in the high temperature without any stable melting or semi-melting phases, which prevents it deposition. One possible way to fabricate the AlN thermal sprayed coatings is using the reactivity of the plasma. Recently we developed the reactive plasma spray (RPS) process of AlN coatings using the atmospheric plasma spray system. The process depends on the reaction between the active nitrogen plasma species with molten powders like aluminum and/or alumina. It was possible to fabricate several thick AlN based coatings. This study will investigate the feasibility of spraying aluminum nitride-alumina-yttria mixtures in nitrogen ambient and its effect on the coatings properties. |