Spark plasma sintering of sub-micron copper reinforced with ruthenium-carbon nanotube composites for thermal management applications

摘要

Submicron copper reinforced with carbon nanotubes-ruthenium composites as suitable material for thermal management applications has been fabricated by Spark plasma sintering (SPS). The slurry of CNT-Ru was uniformly dispersed into copper matrix by mechanical stirring process using ethanol as a mixing medium. The composites powders were initially annealed for 30 min at 550 degrees C with heating rate of 5 degrees C/min under argon. The annealed powders were then consolidated at sintering temperature of 600 degrees C and 650 degrees C with a constant pressure of 50 MPa and the holding time of 5 min. The relative density of 98.15% was obtained for Cu-2 vol%CNT while that of Cu-2 vol%CNT-0.5 vol%Ru was of 97.08%. The Vickers hardness values of Cu-2 vol%CNT-0.5 vol%Ru sintered at 650 degrees C were found to be 130.4 HV. The coefficient of thermal expansion of 2.3 x 10(-6)/degrees C was measured for copper reinforced with 2 vol% CNT sample at 100 degrees C. The thermal conductivity of 323 W/mK and 279 W/mK was measured at 100 degrees C for Cu and Cu-1CNT-0.5 vol%Ru. The X-ray photoelectron spectroscopy was performed on the samples surface in order to determine the effect of additives on the copper surface. XPS revealed that addition of Ru reduced copper oxidation at the surface. (C) 2015 Elsevier B.V. All rights reserved.