| 摘要 |
<p>The magneto-rheological fluid comprises low coercivity, generally spherical magnetic particles dispersed in a liquid medium, the particles consisting of a first group of particles having a first diameter with a standard deviation no greater than two-thirds the value of the second means diameter; and a second group of particles with a second range of diameter sizes and a second mean diameter with a standard deviation of no greater than two-thirds the second means diameter. The major portion of all particles sizes fall within 1-100 microns and the weight ratio of each of the first and second group to the total weight of the magnetic particles is 0.1-0.9, and the ratio of the first mean diameter to the second is 5-100. Also claimed are (i) the fluid that is pourable at ambient conditions in the absence of applied magnetic field but has a yield stress in excess of 10 psi in an applied magnetic field of 1 T or more, the fluid comprising generally spherical, low coercivity, ferromagnetic or paramagnetic metal particles of size 1-100 microns dispersed in liquid medium with dispersing agent; and (ii) the magneto-rheological fluid in which the first group of particles is surfactant-coated carbonyl iron particles and the liquid medium is poly-alpha -olefin, alkyl ester of tall fatty acid or dioctyl sebacate, the fluid optionally comprising dispersed fumed silica.</p> |
