Fabrication of High Thermal Conductivity Tungsten-Coated Diamond/Tungsten Composites by a Rapid Sintering Method

To improve heat transfer in the high heat flux devices, uncoated and tungsten-coated diamond/tungsten composites were prepared by spark plasma sintering (SPS) method. The composition and microstructure of the composites were studied by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results show that uncoated and tungsten-coated diamond/tungsten composites can be prepared by SPS at 1600 degrees C for 3 min and diamond can stably exist in the tungsten-based material, while diamond was destroyed in diamond/tungsten composites after conventional sintering at 1600 degrees C for 120 min. Compared with the interface gap in some areas between uncoated diamond and tungsten, tungsten-coated diamond/tungsten composites can obtain tight interfacial bonding between tungsten-coated diamond and tungsten. The highest thermal conductivity of the tungsten-coated diamond/tungsten composites prepared by SPS was 207 W/(m K), which was nearly 20% higher than the thermal conductivity of pure tungsten (174 W/(m center dot K)), indicating that adding a certain amount of tungsten-coated diamond particles to the tungsten material will improve its thermal performance.