Observing and modeling the sequential pairwise reactions that drive solid-state ceramic synthesis

TL;DR

This paper introduces a thermodynamic modeling framework based on pairwise interfacial reactions to predict and optimize solid-state ceramic synthesis pathways, validated through in situ experiments on YBCO.

Contribution

It presents a novel computational approach combining ab initio calculations with in situ observations to rationalize and design ceramic synthesis routes.

Findings

Rapid YBCO formation from BaO₂ within 30 minutes.

Replacing BaCO₃ with BaO₂ redirects phase evolution.

Model accurately predicts phase evolution pathways.

Abstract

Solid-state synthesis from powder precursors is the primary processing route to advanced multicomponent ceramic materials. Designing ceramic synthesis routes is usually a laborious, trial-and-error process, as heterogeneous mixtures of powder precursors often evolve through a complicated series of reaction intermediates. Here, we show that phase evolution from multiple precursors can be modeled as a sequence of pairwise interfacial reactions, with thermodynamic driving forces that can be efficiently calculated using ab initio methods. Using the synthesis of the classic high-temperature superconductor YBa$_2$Cu$_3$O$_{6+x}$ (YBCO) as a representative system, we rationalize how replacing the common BaCO$_3$ precursor with BaO$_2$ redirects phase evolution through a kinetically-facile pathway. Our model is validated from in situ X-ray diffraction and in situ microscopy observations, which show rapid YBCO formation from BaO$_2$ in only 30 minutes. By combining thermodynamic modeling with in situ characterization, we introduce a new computable framework to interpret and ultimately design synthesis pathways to complex ceramic materials.