Thermal stability of shock-compacted diamond

The heat resistance of shock-compacted polycrystalline diamond (PCD) was in vestigated and compared with that of commercially available PCD. Shock trea tment of PCD with and without silicon was performed by impacting an iron fl yer plate 3.2 mm thick, at a velocity of 2.3 km/s. Neither significant grap hitization nor cracking was observed after heat treatment of the obtained P CD with silicon at temperatures of 1000 and 1200 degreesC for 30 min in vac uum. Vickers hardness of the compacted PCD decreased slightly with increasi ng temperature up to 1200 degreesC, while the hardness remained unchanged a fter this treatment at 1000 degreesC for the PCD with silicon. On the shock -compacted pure PCD, no crack formation was observed after heat treatment a t temperatures of 1000 and 1200 degreesC, but increasing heat treatment tem perature caused an increase in the amount of graphite, and thus the hardnes s decreased. Therefore, the addition of silicon contributes to the improvem ent of the thermal stability of shock-compacted PCD.