THERMODYNAMIC EVALUATION OF INTERACTION IN THE C–Ti–O SYSTEM DURING HIGH-PRESSURE SINTERING OF TITANIUM-COATED DIAMOND POWDER WITH DIAMOND GRAINS

Abstract

The interaction between components during high-pressure sintering of diamond powder with titanium coating of diamond grains is considered. Based on calculations of the change in Gibbs free energy, it is shown that the reactions of oxygen with titanium are thermodynamically more favorable than its reaction with diamond. At a pressure of 8 GPa, titanium remains a heterogen for oxygen up to a temperature of 3000 K, which stops the graphitization of diamond through the gas phase. It is shown that the processes of carbide formation during the sintering of diamond powder under high pressure occur in the case of application of a titanium coating on diamond grains.