Mullite fiber sealing pad with favorable high-temperature rebound resilience fabricated through colloidal processing

Mullite fiber sealing pad composed of chopped fibers and aqueous silica binder, having near-isotropic structure, was fabricated by a combination of vacuum filtration and colloidal processing. The fibers were randomly distributed, overlapping and interlocking to produce the matrix and pure SiO2 binder composed of a glass-ceramic structure firmly bonded fiber laps. A microwave micro-zone heater was adopted to simulate transient aerodynamic heating process and 8-cycle loading–unloading test was conducted at 800 °C. The samples were sintered at 1300 °C with different silica sol concentrations (10.3–20.9 wt%). Mullite fiber pads exhibited high rebound resilience (80.9–87.6%), high compression (24–18%) and moderate Young′s modulus (0.97–3.24 MPa), making it to be a promising high-temperature seal material.