Hexagonal boron nitride ceramic reinforced with a dispersed glass phase and microdomain-extruded glass fibers

Abstract

Hexagonal boron nitride (h-BN) is an important engineering ceramic material. However, its layered structure and poor sinterability often result in suboptimal mechanical properties. In this study, h-BN was simultaneously reinforced with a dispersed ytterbium aluminosilicate (YbAS) glass phase and novel in situ microdomain-extruded glass fibers. In situ–formed glass fibers play a vital role in enhancing the composite’s mechanical properties. h-BN/30 vol% YbAS composite sintered at 1600°C showed optimal mechanical properties, with flexural strength, compressive strength, fracture toughness, and elastic modulus of 436 ± 59 MPa, 1072 ± 86 MPa, 4.2 ± 0.3 MPa·m^1/2, and 90.2 ± 0.1 GPa, respectively. The strengthening mechanisms include the co-reinforcement effect, mechanical locking provided by the YbAS glass fibers, and robust interfacial bonding between the h-BN grains and the YbAS glass phase. The proposed novel microstructural design offers a promising pathway for strengthening ceramic performance.