A room-temperature curable silicate adhesive for cost-effective water- and high-temperature-resistant bonding and potting applications

Silicate inorganic adhesives offer excellent temperature resistance and strong potting compatibility, meeting the current demand for bonding high-temperature structural components and protecting power module resistor components. However, traditional silicate inorganic adhesives often require high-temperature curing, experience reduced structural stability after prolonged exposure to humid environments, and struggle to effectively combine bonding and potting functions in practical applications. To address these issues, a cost-effective room-temperature curable silicate adhesive (RT-SA) was developed by modifying the silicate resin composition, optimizing graded filler systems, and incorporating a composite curing agent system. The composite curing agent system balances curing speed and potting operability, allowing curing at 25 ± 2 °C with a tensile shear strength of 7.70 MPa, while inhibiting alkali metal ion migration to significantly enhance water resistance and result in long-term high resistivity. Additionally, the optimized graded filler systems enhance internal packing density and structural stability, resulting in only a 1.6% loss of bonding strength after 5–20 thermal shock cycles at 500 °C. Importantly, this adhesive demonstrates excellent functional versatility, suitable for both bonding and potting scenarios. This cost-effective, room-temperature-curable, water- and high-temperature-resistant silicate adhesive has significant potential for practical applications in bonding and potting, such as in aircraft thermal protection systems and high-power module potting.