A self-healing strategy for inorganic fillers: Toward practical applications of silicone resin treated at high temperatures for bonding ceramic joints

A high-temperature adhesive composed of a silicone resin (SR) matrix was prepared for bonding ceramic joints. The adhesive primarily consists of boehmite sol as the modifier and B4C, Al and fumed SiO2 powders as inorganic fillers. In this study, the ceramic yield of the adhesive was determined to reach 138% after heat treatment at 1100 °C. The bonding strength of ceramic joints heated at 200 °C was measured as 6.25 MPa and increased to 41.67 MPa after heat treatment at 1000 °C. According to mechanistic analysis, the volume shrinkage induced by the pyrolysis of SR was effectively restrained, and the micro-pores and cracks resulting from the oxidation process of the inorganic fillers can be self-healed by introducing borate. In addition, chemical bonds were introduced at the interfaces, thereby further improving the adhesive strength at elevated temperatures.