V₂O₃–CaO system is one of the fundamental systems in the fields of vanadium extraction and vanadium-containing alloys production. Due to the insufficient experimental study, the data of this system was limited. The present study was carried out between 1300 and 1500 °C (1573–1773 K) at the V2O3-rich region (>56 wt% V₂O₃), with the controlled partial pressure of oxygen (PO2) at 10-10 and 10–11 atm. High-temperature equilibration experiments, quenching technique and electron probe micro-analyser (EPMA) were adopted to determine the microstructures and compositions of phases at high temperature. The results of phase compositions obtained were used to plot a sub-solidus phase diagram, which showed a great discrepancy with existing publications, and 4 solid-phase regions with their phase boundaries were identified in the present study. The solubility of CaO in V2O3 was found to increase slightly with the temperature under both PO2. The study is expected to fulfil the gaps of thermodynamics information in the V₂O₃-containing systems.

V ₂ O ₃ -CaO体系是提钒和含钒合金生产领域的基础体系之一。由于实验研究不足，该系统的数据有限。本研究是在 1300 至 1500  ° C (1573–1773 K) 的富 V2O3 区域（>56 wt% V ₂ O ₃)，氧气 (PO2) 分压控制在 10-10 和 10-11 个大气压。采用高温平衡实验、淬火技术和电子探针显微分析仪（EPMA）对高温相的显微组织和成分进行了测定。获得的相组成结果用于绘制亚固相线相图，与现有出版物有很大差异，本研究确定了 4 个具有相边界的固相区域。发现 CaO 在 V2O3 中的溶解度随温度在 PO2 两种情况下略有增加。该研究有望填补含V ₂ O ₃系统中热力学信息的空白。