Microstructure, mechanical property and bonding mechanism of SiC ceramic joint using a novel Y2Si2O7/Mullite glass-ceramic interlayer

Abstract

Joining of SiC ceramics with a pre-oxidized or unoxidized surface and the subsequent mechanical properties have been studied using Y2O3–Al2O3–SiO2 glass bonding method, and the mechanism of interface bonding was revealed. The joining parameter of interest was temperature from 1400 °C to 1500 °C for a dwell time 10 min. The microstructure, compositions, and interfacial properties were characterized via electron microscopy and X-ray diffractometry. A multiphase glass-ceramic interlayer mainly consisting of Y2Si2O7 and mullite was formed in the joint, which possessed good thermal matching with the SiC substrate. Moreover, the softening temperature of glass-ceramic could exceed to 1200 °C. The joint obtained from the pre-oxidized SiC substrate exhibited a more reliable interface bonding than the unoxidized surface. A preferable shear strength of 48 MPa was achieved within 10 min at 1420 °C. The elemental diffusion at the interface and the chemical bonding between glass-ceramic and SiC contributed to a reliable SiC–SiC joint.