Investigation of magnetorheological grease flow under the influence of a magnetic field

Highly lubricative, self-healing, chemically degradable, anti-flaming and anti-irradiating magnetic gels simply prepared from binary mixtures of Fe3O4 nanoparticles and water

“…To date, magnetic greases, which usually comprise oil-soluble magnetic particles, lubricating base oils and organic thickeners, have been used with successes in various mechanical, electromechanical and biological systems. 16,20,23,24 In addition to reducing the friction and abrasion between two contacting moving parts, they can provide unique continuous lubrication by rapidly lling in depressions and scratches on a rubbed surface under external magnetic elds and counteracting the effect of gravitational and centrifugal forces that are inclined to cause lubricant leakage and external pollution during the lubrication process. 6,32 However, other than aforementioned safety, health and environmental issues due to the frequent use of toxic, ammable and non-degradable organic base oils and additives, such as mineral oils and thickeners, [1][2][3]6,27,37 magnetic greases suffer drawbacks of their relatively complicated preparations and the potential adverse effects of thickening agents on lubricity.…”

“…The resulting aqueous gels can also overcome the crucial issue of traditional magnetic uids while creeping on a sliding surface or leaking due to the inuence of gravitational and centrifugal forces during the lubrication process, thereby effectively eliminating any possible lubrication failures and leading to valid continuous lubrication. 16,23,24 Herein, we report highly lubricative, chemically degradable, anti-aming and anti-irradiating magnetic gels solely constituting of amino-functionalized Fe 3 O 4 nanoparticles and water. The composite nanoparticles can afford gels with low dispersion concentrations in a broad pH range from 2 to 12 aer highspeed centrifugation when they display either strong mutual electrostatic repulsions or weak van der Waals associations.…”

“…The resulting aqueous gels can also overcome the crucial issue of traditional magnetic fluids while creeping on a sliding surface or leaking due to the influence of gravitational and centrifugal forces during the lubrication process, thereby effectively eliminating any possible lubrication failures and leading to valid continuous lubrication. 16,23,24…”

High-velocity micromorphological observation and simulation of magnetorheological gel using programmable magneto-controlled microfluidics system and micro-tube dynamic models

“…Promisingly, based on the variable mechanical properties of MRG in magnetic fields, it can be designed as a magneto-controlled at ms-level, and stable performance mitigation material [14,26,27]. Specifically, by applying excitation magnetic fields, a moderate microstructuresmacromechanical behaviors interrelation can be established, where the microstructures are programmed by adjusting magnetic flux densities [28]. Furthermore, during impact, the compressibility of MRG enables the objects to be protected from peak forces, and particles chains formed by magnetic fields can further dissipate the complex impact energies.…”

Effect of magnetic field on the lubricating performance of nano magnetorheological grease at different temperatures

“…Magnetorheological grease is a colloidal dispersion system comprising magnetic particles and a grease matrix. Under the action of a magnetic field, the magnetic particles in magnetorheological grease can be arranged into chains along the direction of magnetic field (Ye et al , 2022a; Raj et al , 2022). This process has a significant magnetorheological effect.…”