Enhanced comprehensive performance of Y2O3-Al2O3-SiO2 glass filler for SiC brazing by Li2O additive

• Published in: Journal of the European Ceramic Society Vol. 44; no. 10; pp. 5907 - 5916
• Main Authors: Liu, Jiasheng, Bai, Jiawei, Xing, Lili, Ma, Decai, Zhou, Zhou, Lin, Jincheng, Yang, Weiqi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2024
• Subjects: Crystallization behavior; Mechanical properties; Silicon carbide; Wettability; Y2O3-Al2O3-SiO2-Li2O glass filler; Mechanical properties; Wettability; Silicon carbide; Y2O3-Al2O3-SiO2-Li2O glass filler; Crystallization behavior
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2024.03.011

Effects of Li2O additive on the network structure, crystallization behavior, thermal expansion properties and wettability of Y2O3-Al2O3-SiO2 glass were investigated. The results showed that Li2O could depolymerize the network structure, decreasing the characteristic temperatures of glass. The coefficient of thermal expansion of glasses varied from 5.09×10−6 K−1 to 8.03×10−6 K−1 by changing the Li2O addition and heat treatment process. Meanwhile, Li2O inhibited the crystallization of high-melting phases, consequently improving the fluidity of molten glass. The glass with 3 wt% Li2O showed an excellent wettability on SiC ceramic with a contact angle of 18°, and a sound joint mainly consisted of glassy phase was obtained at 1430 ℃ for 30 min. The prepared joints exhibited a shear strength of 119.7±20.3 MPa, which is 5.4 times of that without Li2O. After 3 times of water-quenching from 1200 ℃, the joints remained 68.4% of its original strength, demonstrating graceful reliability. •A series of Y2O3-Al2O3-SiO2-Li2O glass filler was newly-designed for SiC brazing.•Effect of Li2O on the glass structure, crystallization and thermal expansion properties was revealed.•Li2O improved the fluidity of molten glass by inhibiting the formation of high-melting precipitates.•Addition of Li2O increased the shear strength of SiC/SiC joint by 4.4 times (119.7±20.3 MPa).