Influence of Hexagonal Boron Nitride on the Rheological Behaviour of Concentrated Silica Shear-Thickening Fluids

This study systematically explores the shear-thickening (ST) behavior of silica-based suspensions enhanced with hexagonal-boron-nitride (h-BN) nanoparticles. A series of h-BN/SiO ₂ shear-thickening fluids (STFs) with varying concentrations was prepared using mechanical stirring and ultrasonication techniques. The structural and interfacial characteristics of the nanoparticles within the STFs were examined through X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Steady-shear rheological analyses demonstrated pronounced shear-thickening effects and distinct flow responses across different h-BN loadings. At an optimal concentration of 0.1% h-BN, the critical shear rate decreased by 43.18% (from 17.6 s⁻¹ to 10 s⁻¹), while the maximum viscosity increased by 99.2% (from 131.8 Pas to 262.5 Pas). Dynamic oscillatory measurements confirmed that the 0.1% h-BN/SiO ₂ -STF exhibited superior energy dissipation and storage capabilities, showing predominantly elastic behaviour under low stress, while providing effective energy absorption when subjected to high stress. The formulations also demonstrated excellent reversibility, stability, and minimal temperature dependence, underscoring their potential as intelligent damping materials for impact and vibration control applications. Overall, this work presents a new approach for designing high-performance shear-thickening fluids (STFs) with enhanced rheological and thermal stability characteristics.