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E. Neubauer, G. Korb, C. Eisenmenger-Sittner, H. Bangert, S. Chotikaprakhan, D. Dietzel, A.M. Mansanares, B.K. Bein:
"The Influence of Tailored Interfaces on the Mechanical Adhesion Strength and the Thermal Contact Resistance of Copper PVD coatings on Carbon Substrates";
Vortrag: EUROMAT 2003, Lausanne/Schweiz; 01.09.2003 - 04.09.2003.

The knowledge of interfacial properties, such as the adhesion strength between a coating and the substrate, is important in order to optimise material systems for their applications. In many cases besides a good mechanical bonding, good thermal transport properties are requirements for operation under severe conditions.
The background to study the correlation between the mechanical bonding of copper coatings on carbon substrates as well as the determination of the thermal contact resistance at the interface is given by an intensive work on two component materials, so called metal matrix composites based on copper reinforced with carbon fibers.
As found out in former research studies a weak interface in this material system leads to a thermal conductivity which is up to 25% lower compared to theoretical calculations.
In this study a simplified model system (PVD copper coating on a plane carbon substrate) was used. In order to be able to prepare samples with different adhesion strength, plasma pre-treatment and adhesion promoting intermediate layers were used to modify the carbon surface. For characterisation of the adhesion strength of the coatings, a self-made Pull-Off-Adhesion Test was used. This testing equipment allows to measure an adhesion strength of a copper coating up to 800 N/cm2. Parallel to these measurements the Thermal Contact Resistance between coating and substrate was determined by means of a non-destructive photothermal method. By comparing the results of both methods useful information for the optimisation of interfaces in composite materials was collected.