6th EU-Framework Programme

Towards extreme heat conductivity


On December 13/14th 2004 the start of the project "ExtreMat" was celebrated at the Max Planck Institute for Plasma Physics in Garching. "ExtreMat" is a 5 years Integrated Project of the 6th EU Framework Program with 38 partners from research and industry, including Empa. This project aims at providing and industrialising novel knowledge-based materials and their compounds for top-end and new applications in extreme environments in the fields of energy and aerospace.


The project aims at providing and industrialising knowledge-based materials and their compounds for top-end and new applications in extreme environments that are beyond reach with incremental materials development only. Besides self-passivating protection and radiation resistant materials the resulting radical multi-sectorial innovations will span new heat sink materials for demanding thermal management tasks. EMPA is involved in this latter sub-project and in charge of developing, in cooperation with other project partners, heat sink materials with a thermal conductivity exceeding that of pure copper by at least 50% (> 600 W/mK).

As a matter of fact, ever growing performance of microelectronic and semiconductor components leads to dramatically increasing thermal energy densities:  "it has been estimated that, by the year 2010, a single computer chip will hold a billion transistors generating 1000 watts of power; this is more heat per surface unit than that of a nuclear reactor" [Johnson G., The New York Times, 2002; Zhou D.].Such development issues call for new thermal management materials with enhanced thermal conductivity (TC) and adapted coefficient of thermal expansion (CTE).

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FIB-lamella for TEM investigation of the metal/diamond interface microstructure [courtesy S.Meier]

EMPA meets this challenge following the approach of using diamonds as a high thermal conductivity phase dispersed in a dedicated metallic matrix. Actually, owing to its exceptional thermo-physical properties (up to 2200 W/mK and 0.8·10-6/K for TC and CTE @ 25°C, respectively) diamond appears among the most attractive thermal management materials, all the more, considering that the costs for good quality synthetic diamonds have continuously been decreasing in recent years and that these materials have now become widely available.

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Adhesion of Al and Si on the diamond surface [courtesy P.Ruch]

One approach to transfer the properties of diamond to bulk engineering components, is to integrate diamond particles into an appropriate high TC metallic matrix such as Cu, Ag or Al, provided that the metal-diamond interface can meet the demands in terms of bonding strength and heat flow transfer. In the frame of ExtreMat, EMPA will address the fundamental interactions between the nature and surface condition of diamond, the metallic matrix chemistry, the composite process history and the resulting interface (microstructure) formation and the associated thermo-physical properties.


For more information on EMPA's activities in the filed of advanced metal-based composites click here.

For more information on the ExtreMat IP click here.

Contact: Olivier Beffort,