Spark Plasma Sintering of Diamond- and Nanodiamond-Metal Composites

Diamond-metal composites are attractive materials for thermal management and cutting tool fabrication. In order to increase the wettability of the surface of diamond filler particles by certain metals and reduce the interface-associated porosity in sintered composites, coatings are deposited on diamond particles, or alloying additives are introduced into the metal matrices. Nanodiamonds are added to metal matrices to achieve a reinforcing effect. The subject of this chapter is processing of diamond- and nanodiamond-metal composites by spark plasma sintering (SPS). The interest to SPS as a processing method of these materials is stimulated by its capability to rapidly consolidate powder mixtures into dense compacts. In this chapter, the suitability of SPS for diamond-metal composites aimed at different applications is discussed. Recently, the SPS treatment has been used to deposit coatings on micrometer-sized diamond particles. Results of these studies are reviewed. The microstructure development of composites containing nanodiamonds as a reinforcing phase in metal matrices during SPS is analyzed. Future directions of research on the SPS processing of diamond- and nanodiamond-metal composites are suggested.