Characterization of inclusions inhibiting high thermomiotic behavior of Y2W3O12

Abstract

The present study delves into the significant impact of secondary phases created during the formation process of Y2W3O12. Thermomiotic ceramic materials exhibit negative thermal expansion (NTE). Among those ceramics, Y2W3O12 is distinct for having phase stability over a high-temperature range as well as high volumetric NTE. These properties make Y2W3O12 an unprecedented additive for thermal expansion coefficient (CTE) engineering for high-temperature composites. Synthesis of this material is continuously concluded with a higher thermal expansion than the theoretical. To fully take advantage of this material's unique properties, the origin of the mismatched NTE should be fully understood. In this study, the popular solid-state synthesis approach of Y2W3O12 across all synthesis steps was examined in detail. Each secondary Y-W-O phase's contribution to the CTE was calculated, and the final value closely aligns with the measured NTE within 3.7 %, demonstrating the impact of secondary phases on the material's thermal behavior.