Development of High Thermal Conductivity Metal Matrix Nanocomposites for Thermal Management

Carbon nanotubes are a relatively new form of pure carbon with properties that exceed that of diamond and graphite; for example their thermal conductivity which has been calculated to be up to 3 times higher than diamond, their strength which is 100 timesgreater than steel, and their stiffness which is greater than any other material. This unique combination of properties makes carbon nanotubes extremely attractive as a filler material in metal matrix composites. In this Phase II program, high performanceelectronic heat spreaders based on carbon nanotube/ copper metal matrix composites will be developed. Such a composite should be the ideal heat spreader material, exhibiting high thermal conductivity (>1000W/mK), a tailorable thermal expansion, relativelylow cost (10-100x cheaper than CVD diamond), high stiffness, strength, and toughness, low density, and large area capability. This Phase II program will develop a detailed understanding of the processing-structure-property relationships in such materialsin order to optimize their performance. Numerous processing techniques will be evaluated such as hot pressing, gas pressure infiltration and electroplating to form these composites. Both the bulk and carbon/copper interface structures will be thoroughlycharacterized. Mechanical and thermal properties, including expansion and conductivity will be measured and optimized.