• • The composite with 40 wt% hBN content achieves a flexural strength of 183.4 MPa and fracture toughness of 2.06 MPa m1/2, representing 3.6-fold and 4-fold improvements over pure fused SiO2 (52.2 MPa and 0.58 MPa m1/2), enabling structural use in high-stress aerospace components.
• • Dielectric constant remains low at 3.58–3.69 and dielectric loss below 0.0087 at 1 MHz, preserving signal integrity for radome and electronic communication applications despite mechanical reinforcement.
• • The phase-transition-assisted synthesis via SPS yields randomly oriented hBN nanoplates that force crack propagation along grain boundaries, enhancing toughness without sacrificing dielectric performance—a critical advantage over conventional reinforcements like Si3N4 or AlN that raise dielectric loss.
• • The process achieves these properties while maintaining relative density and Young's modulus (values not explicitly stated but implied by Figure 3), indicating a scalable route for manufacturing high-performance SiO2-based ceramics.