On critical aspects of infiltrated Al/diamond composites for thermal management: Diamond quality versus processing conditions

Al/diamond composites containing diamond particles of different qualities have been manufactured by gas pressure-assisted metal infiltration and characterized by thermal conductivity (TC) measurements. The results show that the intrinsic thermal conductivity of diamond (varied with the diamond quality) plays a minor role on TC. TC is mainly governed by the Al–diamond interface characteristics, which are determined by a proper control exerted through processing conditions. Albeit a very low cost and low quality diamond is used, a high value of 667 W/m K has been measured for Al/diamond composites produced under optimized processing conditions. Values above 740 W/m K are reported for the best diamond quality explored in this work. These experimental results, which assign the control over TC mainly to the interface conductance, suggest that many of the limiting values of TC reported in literature for the different explored metal–diamond systems, need to be reconsidered by proper precise control of interface evolution.