Abstract: BaO-CaO-Al₂O₃-B₂O₃-SiO₂ glass-ceramics have attracted significant attention in high-temperature sealing applications due to their high coefficient of thermal expansion (CTE) and excellent high-temperature resistance. In this work, multiple rare-earth oxides (Ln₂O₃, Ln = La, Nd, Sm, Tb, Y, Er, Yb, Sc) were introduced, and the effect of configurational entropy on the network structure, thermal behavior, crystallization characteristics, and high-temperature performance of BCABS-Ln glasses were systematically investigated. The results show that as the number of rare-earth components increases from 3 to 8, the glass network evolves toward a higher degree of polymerization, accompanied by the transformation of [BO₃] to [BO₄] units and enhanced network connectivity. Combined with molecular dynamics simulations, the bridging oxygen content increases from 47.9% to 54.8% with increasing entropy, and the reconstruction of boron coordination leads to an increase in Si-O-B linkages. Meanwhile, rare-earth cations exhibit local enrichment in the high-entropy system. With increasing entropy, the glass transition temperature (T_g) gradually rises within the range of 684.6-694.7 ℃, while the crystallization peaks decrease, indicating suppressed crystallization. During long-term heat treatment up to 10000 h, the dominant crystalline phase of BCABS-Ln glass-ceramics remains the highly stable Ba_0.9Ca_0.1SiO₃ phase. The CTE values range from 9.67 × 10^-6 to 11.34 × 10^-6 K^-1 (30-550 °C), the composition containing five rare-earth elements (La, Nd, Sm, Er, and Yb) exhibits a CTE degradation of only 2.0% after long-term thermal exposure. The introduction of high-entropy rare-earth oxides effectively enhances the network polymerization and thermal stability of BCABS glasses through the synergistic regulation of network structure and local coordination environments, demonstrating promising potential for applications in high-temperature sealing materials such as solid oxide fuel cells and oxygen sensors.

Key words: high-temperature sealing glass, molecular dynamics simulation, rare-earth oxides, high entropy