Performance improvement of Si3N4/BN slurry and porous ceramics caused by the synergistic effect of BN surface functionalization and high light transmission of SiO2

The fabrication of porous Si 3 N 4 /BN ceramics for high-temperature radomes via vat photopolymerization is hindered by excessive slurry viscosity, which restricts the recoating process, and by limited curing depth. To overcome these challenges, we developed a high-performance slurry using a synergistic strategy combining BN surface functionalization with optical modulation via SiO 2 . Ultrasonic-assisted hydrolysis and silane coupling significantly enhanced interfacial compatibility with the resin, reducing viscosity from 20.83 to 4.51 Pa·s at a shear rate of 30 s −1 . Simultaneously, the incorporation of refractive-index-matched SiO 2 effectively suppressed light scattering, thereby increasing curing depth and structural integrity. Furthermore, SiO 2 regulated liquid-phase behavior during sintering to optimize the microstructure. The resulting ceramics exhibited an exceptional property balance: 42.14 % porosity, 68.2 MPa flexural strength, a dielectric constant of 2.56, and a loss tangent of 6.85 × 10 −3 . These metrics satisfy the stringent requirements for wave-transparent applications, offering a robust pathway for manufacturing complex-shaped components.