E. Neubauer

The influence of mechanical adhesion of copper coatings on carbon surfaces on the interfacial thermal contact resistance

The weak mechanical and thermal interface in Copper based Metal Matrix Composites (MMCs) reinforced by carbon fibers is the background of this research study. In order to investigate the mechanical adhesion strength and the thermal contact resistance between copper and carbon, a simplified model system based on coated flat carbon substrates has been used. Cu coatings of approximately 1 μm thickness on intermediate Ti bond layers have been deposited on carbon substrates by a sputter deposition process. The resulting different adhesion strengths between coating and substrate have been measured by means of a pull-off method, and non-destructive photothermal method, giving information on the depth-resolved thermal properties of the samples has been used to determine the Thermal Contact Resistance (TCR). By combining the results of mechanical adhesion tests and of photothermal IR radiometry, the correlation of the mechanical adhesion of Cu coatings on Carbon surfaces with the interfacial thermal contact resistance has been analysed.

AFM and AUGER investigations of as-deposited and heat treated copper coatings on glassy carbon surfaces with titanium intermediate layers

Copper carbon composites are a prospective material for application as heat sink material in thermal management applications. One of the main drawbacks of this material combination is the lack of adhesion between copper and carbon. In order to improve the interfacial properties in this system a basic investigation on carbon substrates was done, where the influence of an adhesion promoting intermediate layer was investigated. Besides the study of the influence of a Ti intermediate layer on the growth mode and surface topography of a copper coating, the diffusion of Ti after a heat treatment was analysed by using Auger electron spectroscopy.