Preparation and performance investigation of modified silicate-based high-temperature resistant adhesives for quartz glass

This work systematically investigated the influence of silica-zirconia synergy on sodium silicate bonding of quartz glass. Multiple groups of adhesives with different compositions were prepared by systematically regulating adhesive solution concentration and additive types/ratios. Bonding performance and action mechanisms were deeply discussed through microstructural analysis and mechanical property tests. It was found that nano-ZrO2 played multiple roles in the sodium silicate adhesive system: firstly, thermal stability of amorphous sodium silicate was effectively improved, with decomposition and crystallization processes significantly retarded; secondly, a new glassy system was formed at 500−600 °C, enhancing adhesive matrix cohesive strength; thirdly, high-temperature crystallization of sodium silicate was induced as a crystal nucleus, achieving strengthening via multiphase composite; fourthly, an oxygen-rich cubic ZrO2 structure was formed at high temperatures to compensate for adhesive layer mass loss. Experimental results showed that the NSZ adhesive exhibited optimal performance at 30 % sodium silicate concentration and 1:1 SiO2/ZrO2 mass ratio. After room-temperature curing and 1200 °C sintering, bonding strengths reached 9.34 MPa and 12.15 MPa, respectively. Bonding strength remained above 4.5 MPa after 20 thermal cycles or thermal shocks at 800 °C and 1000 °C. The thermal expansion coefficient of NSZ decreased to 4.03 × 10−6 K−1 after 1200 °C treatment, effectively improving joint thermal cycle life.