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2100 |
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Tuesday, May 04, 2010, Hullet Room 9:20 AM Cold Spraying 3 |
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Defined metallization of thin ceramic substrates via cold spray process |
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Christian Rupprecht* / Chemnitz University of Technology, Germany Bernhard Wielage / Institute of Composite Materials, Germany Thomas Grund/ Institute of composite Materials, Germany Sabine Kümmel/ Institute of Composite Materials, Germany Jürgen Wilde/ Albert-Ludwig-University, Germany Eugen Rastjagajev/ Albert-Ludwig-University, Germany |
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Power electronic components usually consist of ceramic base materials that are coated with geometrically defined copper circuits. The most commonly used state-of-the-art process for the application of these electric circuits is the so called DCB (direct copper bonding), a technology containing several manufacturing steps including reactive furnace coating and physical as well as chemical structuring. Main attributes of these coatings are electrical and thermal conductivities in the range of copper bulk material and a good heat transfer from the circuit into the ceramic substrates. However, production and use of DCB substrates are cost intensive. Therefore simple, flexible and cost-effective solutions are increasingly demanded for integrated power electronic devices, which often do not require the high DCG performances. Cold gas spraying (CGS) meets these demands. It is employed to produce dense, well adherent and oxide free coatings whose properties are comparable to the respective bulk material. The CGS metallisation of non-conductive parts for power electronic devices permits a direct assembly and contacting of semi-conductors. The paper will give recent results for the evaluation of this method. Thin Al2O3 substrates are CGS-coated with an aluminium / copper coating system that allows both good adhesion and good electric properties. A comprehensive characterisation of the coating and the bonding mechanism to the ceramic base material is given. Additionally, power electronic components are produced using the CGS substrates. The performances of the so produced integrated components regarding to their electric and thermal properties as well as their long-term behaviour are determined and compared to the state-of-the-art solutions. |