Phase Diagram for the System RuO2-TiO2 in Air

• Published in: Journal of phase equilibria and diffusion Vol. 29; no. 2; pp. 136 - 140
• Main Authors: Jacob, K.T., Subramanian, R.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.04.2008; Springer Nature B.V
• Subjects: Basic and Applied Research; Ceramics; Composites; Crystallography and Scattering Methods; Engineering Thermodynamics; Glass; Heat and Mass Transfer; Metallic Materials; Natural Materials; Physics; Physics and Astronomy; Thermodynamics; phase diagram; thermodynamic properties; miscibility gap; thermodynamic computations; solid solution; peritectoid reaction
• ISSN: 1547-7037; 1863-7345; 1934-7243
• DOI: 10.1007/s11669-007-9236-1

There are conflicting reports in the literature regarding solid solubility in the system RuO 2 -TiO 2 . To resolve this issue a few experiments were conducted in air at 1673, 1723, and 1773 K. The results show limited terminal solid solubility. There is an extended solid-state miscibility gap that intersects the decomposition curve for the RuO 2 -rich solid solution generating a peritectoid reaction at 1698 K. The measured equilibrium compositions of the solid solutions are used to develop a thermodynamic description of the oxide solid solution with rutile structure. Using the subregular solution model, the enthalpy of mixing can be represented by the expression, . The binodal and spinodal curves and T-X phase diagram in air are computed using this datum and Gibbs energy of formation of RuO 2 available in the literature. The computed results suggest that equilibrium was not attained during solubility measurements at lower temperatures reported in the literature.