The adjacent relation of primary phase fields and corresponding invariant reactions of the system CaO‐SiO₂‐Nb₂O₅‐La₂O₃ are of great importance for the study on its phase diagram. In the present work, the phase equilibrium in the high w(La₂O₃) region of CaO‐SiO₂‐Nb₂O₅‐La₂O₃ system was studied by thermodynamic equilibrium experiment. The adjacent relation of primary phase fields was determined and represented in the form of adjacent tetrahedrons. The Alkemade Rule applicable to quaternary phase diagram was deduced, which can be used to infer the liquidus temperature trend on univariant curves. The rule was then used to determine the possible temperature range of invariant reactions corresponding to the adjacent tetrahedron in CaO‐SiO₂‐Nb₂O₅‐La₂O₃ system, and the result was shown in the form of Schairer diagram. Finally, the reaction types of five invariant points were determined according to the Lever Rule for quaternary phase diagram, including:

中文翻译：

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CaO-SiO2-Nb2O5-La2O3体系的初生相场的邻接关系和不变反应

CaO-SiO ₂ -Nb ₂ O ₅ -La ₂ O ₃体系的初相场的相邻关系以及相应的不变反应对于研究其相图非常重要。在目前的工作中，CaO-SiO ₂ -Nb ₂ O ₅ -La ₂ O ₃的高w（La ₂ O ₃）区域中的相平衡通过热力学平衡实验研究了该系统。确定了初级相场的相邻关系，并以相邻四面体的形式表示。推导了适用于四元相图的Alkemade规则，该规则可用于推断单变量曲线上的液相线温度趋势。然后使用该规则确定与CaO-SiO ₂ -Nb ₂ O ₅ -La ₂ O ₃系统中的相邻四面体相对应的不变反应的可能温度范围，结果以Schairer图的形式显示。最后，根据四元相图的杠杆规则确定了五个不变点的反应类型，包括：