Optimizing phase stability and synthesis of calcium/magnesium vanadates for low-temperature cofired ceramics: Phase diagram study and thermodynamic modelling

• Experiments were conducted on the CaO/MgO–V 2 O 5 system. • A thermodynamic model was developed for the system. • The database was applied to design and evaluate vanadates for LTCC. Calcium and magnesium vanadates in the CaO-V 2 O 5 and MgO-V 2 O 5 systems have attracted considerable attention as potential low-temperature cofired ceramics (LTCC) owing to their relatively low melting temperatures, wide compositional tunability, and promising dielectric performance. In this study, key phase diagram experiments were conducted for both systems using X-ray diffraction (XRD) and simultaneous thermal analysis (STA). Notably, Ca 7 V 4 O 17 was identified in the CaO-V 2 O 5 system. The thermodynamic modeling of these two systems was reconstructed using the CALPHAD (CALculation of PHAse Diagrams) approach, incorporating a critical evaluation of all available phase diagram data and thermodynamic properties. The experimental results were successfully reproduced across the entire compositional range, yielding a self-consistent set of model parameters for both solid and liquid phases. The developed thermodynamic database was further applied to simulate synthesis conditions and evaluate the phase stability of calcium and magnesium vanadates, providing valuable insights into their potential application as LTCC materials.