Abstract No.:	2836
Title:	Main bonding mechanisms of CGS sprayed aluminium on Al2O3 substrates as a function of deposition conditions
Authors:	Thomas Grund / Institute of Materials Science and Engineering, IWW, Chemnitz University of Technology, Deutschland Bernhard Wielage / Institute of Materials Science and Technology, IWW, Germany Sabine Kümmel*/ Institute of Materials Science and Technology, IWW, Germany Philipp Löschner/ Institute of Materials Science and Technology, IWW, Germany
Abstract:	In contradiction to metal substrates, adhesion mechanisms of cold-sprayed coatings on ce-ramics and other brittle materials are not fully revealed. The state of the art of science and technology merely discusses physical and chemical phenomena observed without system-atic and statistic variation of substrate and process parameters that would lead to correla-tions between process and coating performance. Due to the resulting gap of knowledge be-tween cause and effect, which avoids narrowly reproducible coating properties, the cold-spray metallisation of e.g. alumina substrates has not yet been transferred into industrial mass production, although it shows a high application potential. In this work a systematic variation of the properties of ceramic substrates is presented. Using the example of coating Al2O3-substrates with pure aluminium via cold-gas spraying the varia-tion includes substrate (surface) properties as well as spray process parameters. So, correla-tions could be made between process parameters like spray transition velocity, powder tem-perature or substrate temperature and coating properties like tensile bond strength or mor-phology of fraction surface. The microstructure investigations are complemented by scanning electron microscopy and electron backscatter diffraction (EBSD) within the coating/substrate interfaces to describe the crystallographic state within that zone. The accomplished investigations hence allow the description of the main bonding mecha-nisms of cold-gas-sprayed aluminium on alumina substrates as a function of the specific deposition conditions.

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