Synergistic regulation of color and mechanical properties of silicon nitride ceramics via engineering hollow structures of Eu-enriched secondary phases

Abstract

Si₃N₄ ceramics, renowned for their superior mechanical properties, are widely regarded as the most promising materials for electronic device casing. This is particularly evident in the context of 5th generation mobile networks, where they outperform both glass and zirconia. However, achieving a synergetic balance between color and mechanical properties remains a significant challenge. In this study, we propose the use of phase separation in liquid phases, supported by a novel Eu₂O₃-YAG-MgO system, to engineer hollow structures. This approach aims to achieve high-toughness colored Si₃N₄ ceramics. The resulting hollow structure not only acts as a reinforcing phase in response to the stress field caused by lattice mismatch but also serves as one of the dominant chromophores. This is achieved through the 5d→4f transition of Eu²⁺ coupled with the ⁵D₀→⁷F_J transition of Eu³⁺ under photon excitation. These findings offer new insights into the development of high-performance Si₃N₄ ceramics with well-controlled color.

Keywords

Si₃N₄ ceramics / Eu ions / hollow structures / optical properties / mechanical properties

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