Phase formation in the B-BN-B2O3 system at high pressures and temperatures: The wettability of the phases with copper-based melts

Multiphase materials, including the B6N boron subnitride, B6O boron suboxide, and cBN cubic boron nitride, have been obtained from the initial β-rhombohedral or amorphous boron, hBN hexagonal graphite-like boron nitride and B2O3 amorphous boron oxide at a pressure of 8 GPa and temperatures from 2100 to 2900 K in a toroid high-pressure apparatus. The hardness of the resulting materials has been measured. The formation of ternary phases in the B-BN-B2O3 system has not been observed. The wettability of the resultant materials with copper-based melts has been studied. An addition of 10 mol % Ti to the copper melt has been found to decrease the contact angle to a value lower than 20 deg.