The present work represents the second part of a series of instructional papers on methods of derivation of phase diagrams, particularly quaternary systems relevant to ceramic-metal bonding. These diagrams are generated using reported phase equilibria data, geometric requirements of the phase rule, and some assumptions. The precise steps to generate and confirm these diagrams are relatively straightforward and they require no thermodynamic calculations or model building. Many aspects of experimental data can be interpreted in a straightforward fashion with a knowledge of the phase equilibria. These conclusions often clarify or refute the explanations offered by the authors of published wetting and bonding studies. In the three cases discussed in the present work, it is clear that alloy-ceramic joins equilibrate to form interfaces in quaternary subsystems with defined solid phases and unique liquids in proportions that can be estimated. This is a critical point that receives little consideration in the literature. The equilibria between these phases can validate experimental observations such as the formation of reaction products, the relative amounts of these phases, the failure to detect expected phases, the absence of phases that are thermodynamically stable, the direction of diffusion, potential reaction paths, the degree of spreading, the reaction layer thickness, and other features.
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