A simple example of an isothermal thermodynamic phase diagram for a quaternary system composed of a ternary A–B–C alloy reacting with a single oxidant (O) has been calculated assuming that oxides are insoluble and that they do not interact with each other. The 2D thermodynamic diagrams of the ternary metal–oxygen systems composed of the three types of binary alloys plus the oxidant are reviewed first, and then the 2D sections of the 3D phase diagram along planes of constant values of one of the variables involved are explored in detail. Finally, the structure of the 3D diagram is presented by means of appropriate figures and is discussed by examining in detail the connections between the critical curves, surfaces and volumes in 3D space with the corresponding critical features, including points, curves and surfaces, of the 2D sections. In addition, the possible application of thermodynamic diagrams to predict the nature of the oxidation products is briefly discussed in combination with the concept of oxidation maps.

中文翻译：

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三元合金暴露于单一氧化剂的热力学相图

假设氧化物不溶且它们不相互作用，计算了由三元 A-B-C 合金与单一氧化剂 (O) 反应组成的四元系统的等温热力学相图的简单示例。首先回顾了由三种类型的二元合金和氧化剂组成的三元金属-氧系统的二维热力学图，然后沿着所涉及的一个变量的恒定值平面探索了 3D 相图的二维截面。细节。最后，3D 图的结构通过适当的图形表示，并通过详细检查 3D 空间中的关键曲线、曲面和体积与相应的关键特征（包括点、曲线和曲面）之间的联系进行讨论。二维截面。此外，