Abstract

Theoretical and experimental studies of the NaF–Na₃ClMoO₄–Na₃ClWO₄ stable secant triangle of the NaF–NaCl–Na₂MoO₄–Na₂WO₄ four-component system have been carried out. The review of the literature concerned with the boundary elements of the title system has shown two options for the numbers and compositions of crystallizing phase: in case the solid solutions are stable, two solid phases would be formed, and in case of their decay, three solid phases would. The experimental tools used to study the NaF–Na₃ClMoO₄–Na₃ClWO₄ system were differential thermal analysis (DTA) and X-ray powder diffraction (XRD). The melting point and composition of the mixture that correspond to point d, which lies on monovariant curve e₁e₂ connecting binary eutectics, have been determined. X-ray powder diffraction showed two solid phases, namely, NaF and Na₃ClMo_xW_{1 – x}O₄ continuous solid solutions (CSS), in an alloy of point d composition. The nonexistence of invariant points in the title system has been shown. The CSS based on Na₃ClMoO₄ and Na₃ClWO₄ are stable. The projection of the phase assemblage of the system on the composition triangle is represented by two crystallization fields of the terminal components: a sodium fluoride field, which is the dominant one, and a Na₃ClMo_xW_{1 – x}O₄ CSS field.

中文翻译：

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NaF-NaCl-Na2MoO4-Na2WO4 四组分体系的 NaF-Na3ClMoO4-Na3ClWO4 稳定三角形中的相平衡

摘要

对NaF-NaCl-Na ₂ MoO ₄ -Na ₂ WO ₄四组分体系的NaF-Na 3 ClMoO 4 -Na 3 ClWO 4 稳定割线三角形_进行了_理论和_实验研究_。对与标题系统边界元素有关的文献的回顾表明，结晶相的数量和组成有两种选择：如果固溶体稳定，则形成两个固相，如果它们衰变，则形成三个固相。固相会。用于研究NaF–Na ₃ ClMoO ₄ –Na ₃ ClWO ₄体系的实验工具是差热分析（​​DTA）和X射线粉末衍射（XRD）。已确定了对应于点d的混合物的熔点和组成，点 d 位于连接二元共晶的单变量曲线e ₁ e _2上。X射线粉末衍射显示d点成分的合金中有两个固相，即NaF和Na ₃ ClMo _x W _{1 – x} O ₄连续固溶体(CSS) 。标题系统中不存在不变点已经被证明。基于Na ₃ ClMoO ₄和Na ₃ ClWO ₄的CSS是稳定的。系统相组合在组成三角形上的投影由末端组分的两个结晶场表示：氟化钠场（占主导地位）和Na ₃ ClMo _x W _{1 – x} O ₄ CSS 场。