Experimental and calculated phase equlibria in the cubic BN–Ta–C system

Theoretical and experimental studies of cubic BN mixed with Ta and TaC in the 1:1 molar ratio are presented. From theoretical calculations it follows that Ta reacts with boron nitride forming additionally two phases: tantalum boride and tantalum nitride. Experimental cBN-phase composites were prepared by high pressure hot pressing. The samples were characterized after heat treatment using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).