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 Si 3 N 4 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‐Y 2 O 3 ‐Er 2 O 3 ‐Yb 2 O 3 ) leads to high‐performance ceramics of homogenous microstructure and pure GB (YErYb) 2 Si 3 O 3 N 4 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.