Spark Plasma Sintering of Diamond Binderless WC Composites
A new method was developed to fully consolidate binderless tungsten carbide and diamond powders by means of spark plasma sintering (SPS) in current‐control mode (CCm). Below 900°C, the 2 cm diameter sample was slowly heated by
a dc current of 1000 A. Above 900°C the imposed current was suddenly raised to 4000 A. The combination of the relatively high heating rate of 2000°C/min and the relatively short holding time of 1.5 min (above 1300°C) was successful to fabricate fully dense binderless
WC/diamond composite. No graphitization of diamond was detected after ultrafast sintering as confirmed by optical and SEM microstructure observations, XRD and Raman analysis. The sample showed very high wear
resistance in comparison to fully dense monolithic binderless WC compacts. The developed method, unlike previously published works, did not require any diamond coating to prevent diamond graphitization.