Design of interfacial Cr3C2 carbide layer via optimization of sintering parameters used to fabricate copper/diamond composites for thermal management applications

Abstract

To produce metal-diamond composite materials with high thermal conductivity, it is important for a high-quality carbide interface to exist between the metal matrix and diamond. The addition of carbide-forming elements to the matrix positively influences the interfacial thermal conductance (ITC), and is an effective method for improving the bulk thermal conductivity of composite materials. Diamond powder was mixed with Cu0.65Cr alloy powder, using a 1:1 volume ratio. The pulse plasma sintering (PPS) parameters were optimized to control the carbide interface between the diamond and matrix. The microstructures and phase compositions of the fabricated materials were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The interfacial layer was characterized using SEM and focused ion beam (FIB) techniques. The residual Cr content of the matrix was estimated, to determine its influence on the thermal properties of the matrix. To calculate the ITC, differential effective medium (DEM) and Hasselman-Johnson (H–J) models were used. The highest thermal conductivity of 687Wm−1K−1 was achieved by a composite material that was fabricated at 850°C over a period of 10min, which had an 81-nm-thick interfacial carbide layer. An ITCDEM value of 5·107Wm−2K−1 was obtained.