Phase formation capability and compositional design of β-phase multiple rare-earth principal component disilicates.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36882392.
- Also identified by DOI 10.1038/s41467-023-36947-6 and PMC identifier 9992687.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
A key strategy to design environmental barrier coatings focuses on doping multiple rare-earth principal components into β-type rare-earth disilicates (RE<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>) to achieve versatile property optimization. However, controlling the phase formation capability of (nRE<sub>xi</sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> remains a crucial challenge, due to the complex polymorphic phase competitions and evolutions led by different RE<sup>3+</sup> combination. Herein, by fabricating twenty-one model (RE<sup>I</sup><sub>0.25</sub>RE<sup>II</sup><sub>0.25</sub>RE<sup>III</sup><sub>0.25</sub>RE<sup>IV</sup><sub>0.25</sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> compounds, we find that their formation capability can be evaluated by the ability to accommodate configurational randomness of multiple RE<sup>3+</sup> cations in β-type lattice while preventing the β-to-γ polymorphic transformation. The phase formation and stabilization are controlled by the average RE<sup>3+</sup> radius and the deviations of different RE<sup>3+</sup> combinations. Subsequently, based on high-throughput density-functional-theory calculations, we propose that the configurational entropy of mixing is a reliable descriptor to predict the phase formation of β-type (nRE<sub>xi</sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>. The results may accelerate the design of (nRE<sub>xi</sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> materials with tailored compositions and controlled polymorphic phases.