Developing High‐Performance Ceramics from Multicomponent Grain Boundary Entropy Design

Abstract Grain boundary (GB) glassy phase often results in poor ceramic performances. Here, a Multicomponent Grain Boundary Entropy (MGBE) descriptor extracted from high‐throughput first‐principle calculations is proposed to capture the nature of high‐entropy GB phases in ceramics. In a Si₃N₄ ceramic model system, MGBE is found to have a direct correlation with GB phase crystallinity, element segregation, and formation of pores. The predicted highest MGBE sintering additive combination (MgO‐Y₂O₃‐Er₂O₃‐Yb₂O₃) leads to high‐performance ceramics of homogenous microstructure and pure GB (YErYb)₂Si₃O₃N₄ phase without observable glassy film. Conversely, low MGBE additives result in a substantial amount of GB glassy phase, element segregation, and pore clusters. The MGBE descriptor can make a rapid screening of multicomponent sintering additives, offering a novel approach for rational designing of ceramics with targeted microstructure and performances.