In the literature about magnetorheological fluids (MRFs), with both theoretical and experimental results of physical models to explain the magnetorheological (MR) effect, often the MRF is prepared with only two components, a magnetic dispersed phase and a carrier liquid, while attempting to keep the MRF formulation as simple as possible. On the other hand, many patents of MRF include three, four or more components, such as some surfactant and thixotropic additives. In order to formulate a good and reliable MRF for different applications such as MR shock absorbers, clutches and brakes, the MRF redispersibility is a challenge, but necessary key property for out-of-lab real-world applications. In this chapter, we show how to measure and evaluate the MRF redispersibility.

Chapter Contents:

• 1.1 Introduction
• 1.1.1 Methodology of the redispersibility test
• 1.2 Results and discussion
• 1.2.1 Effect of sedimentation time
• 1.2.2 Effect of additives in MRF formulation
• 1.2.3 Effect of centrifuging the MRF
• 1.2.4 Long-time settling (1-year) redispersibility
• 1.2.5 Redispersibility of MRF with 48 vol.%
• 1.3 Conclusions
• Acknowledgments
• References

Inspec keywords: shock absorbers; clutches; thixotropy; magnetorheology; brakes; additives; magnetic fluids; magnetic particles

Other keywords: thixotropic additives; clutches; magnetorheological effect; surfactant additives; brakes; magnetorheological fluids; MR shock absorbers; MRF formulation; MRF redispersibility; magnetic dispersed phase

Subjects: Fine-particle magnetic systems; Magnetic liquids; Mechanical components; Engineering materials; Electrorheological and magnetorheological fluids