Thermal conductivity of diamond/Ag composites with chromium carbide coated diamonds for the building materials of high power modules

摘要

This paper reports on a study of the preparation and characterisation of diamond/Ag composites for the building materials of high power modules. The Cr_7C_3 coated diamond particles are utilised to improve the interfacial bonding between the Ag and diamond and composites are prepared by hot pressing technique. The characteristics of Cr_7C_3 coating layers were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the Cr_7C_3 coatings on the diamonds result in a strong interfacial bonding and a greatly enhanced thermal conductivity of the composites. A largely enhanced thermal conductivity of 768 W m~(-1) K~(-1) is obtained in Cr_7C_3 coated composites, which increases 168% relative to that of uncoated composites at 65% diamond volume fraction. The measured thermal conductivity agrees reasonably well with the predictions by a differential effective-medium (DEM) model.