High pressure phase equilibria in the Li3N-BN system: in situ studies

• Published in: Materials letters 1997-08, Vol.32 (2-3), p.179-184
• Main Authors: Solozhenko, Vladimir L., Turkevich, Vladimir Z.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cubic boron nitride; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Heat capacities of solids; High pressure; In situ studies; Li-B-N system; Phase equilibria; Physics; Specific phase transitions; Thermal properties of condensed matter; Thermal properties of crystalline solids; Thermodynamic properties
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(97)00025-6

Powder diffraction of synchrotron radiation at pressures up to 6.3 GPa and DTA at ambient pressure were used to study phase equilibria in the Li3N-BN system at temperatures up to 1820 K. The construction of the Li3N-BN quasibinary section of the Li-B-N ternary system has been refined. The melting of the high-pressure phase of Li3BN2has been shown to be of an incongruent nature. The existence of the Li3BN2(O) ⇄ L + BN peritectic equilibrium at 1620 K and 5.3 GPa has been established. It was shown that this peritectic reaction defines the lowest possible temperature of formation of cubic boron nitride in the Li3N-BN system (1670 ± 50 K in the 5.3–6.3 GPa range).