The influence of bentonite content on the performance characteristics of magnetorheological fluids

Abstract

This study investigates the influence of bentonite concentration (0–2.0 wt%) on the properties of bentonite-modified magnetorheological fluids (BMRFs). The results demonstrate that bentonite significantly enhances sedimentation stability by forming a three-dimensional network structure, with the 1.2 wt% sample exhibiting optimal performance. However, a high concentration of 2.0 wt% led to a complete loss of fluidity, while at 1.6 wt%, partial caking was observed. Rheological tests confirmed that bentonite addition improves the magnetorheological effect, promotes earlier magnetic saturation, and expands the linear viscoelastic region. Furthermore, redispersibility evaluation indicated that the addition of bentonite enabled the BMRFs not only to recover but also to improve their original performance after redispersion, with increases in both apparent viscosity and storage modulus. The 1.2 wt% sample, in particular, demonstrated stronger stability. In contrast, the 2.0 wt% sample exhibited irreversible property degradation. This study provides a valuable formulation for developing high-performance MRFs with balanced stability and redispersibility.