Rheological properties of silica-based shear thickening fluids reinforced with silicon nitride and carbon nanotubes

Abstract

This study fabricates SiO₂/Si₃N₄/MWCNT shear-thickening fluids (STFs) based on nanoparticles silicon dioxide (SiO₂), silicon nitride (Si₃N₄), and multi-walled carbon nanotubes (MWCNT). The research investigates the effects of MWCNT mass fraction, ambient temperature, and gap distance on the shear thickening (ST) performance through rheological experiments. Scanning electron microscopy and X-ray diffraction confirm the presence of MWCNT and Si₃N₄ nanoparticles within the multiphase STF (MSTF), as well as their interactions with SiO₂ nanoparticles. Steady shear rheology tests reveal significant rheological behavior and a pronounced ST effect in SiO₂/Si₃N₄/MWCNT-STF with varying mass ratios. The optimal mass ratio of SiO₂, Si₃N₄, and MWCNT is found to be 20:2.5:0.8, at which point the ST performance of the MSTF is maximized. The peak viscosity increases from 65.83 Pa s (20:2.5:0.2) to 516.2 Pa s (20:2.5:0.8), while the critical shear rate decreases from 63.1 s⁻¹ to 6.31 s⁻¹. Dynamic rheology tests demonstrate that the 20%SiO₂/2.5%Si₃N₄/0.8%MWCNT-STF exhibit not only significant energy storage and dissipation capabilities but also enhanced rate sensitivity in energy storage and dissipation compared to silicon-based STF (SiO₂-STF) under lower rate excitations. Temperature sensitivity studies indicate that MSTF maintain excellent ST characteristics even in high-temperature environments. In comparison to SiO₂-STF, the variation in peak viscosity and critical shear rate of MSTF with increasing temperature is significantly reduced, demonstrating superior temperature stability and offering potential for engineering applications in higher temperature environments.

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