Low-temperature magnetic fluid stabilized with mixed fatty acids

摘要

It is established that the working temperature range of a magnetic fluid (MF) stabilized with a mixture of oleic and linoleic acids is widened to -100°C and, when the linoleic acid mass fraction in the mixed surfactant is 10%, the fluid becomes unpolymerizable. The stability of the MF with respect to a coagulant (isopropanol) is studied. The dependence of the magnetic susceptibility of the stable fraction of the fluid on the volume fraction of the alcohol almost coincides with the data obtained for an MF stabilized with oleic acid. The MF is separated into coarse and finely dispersed fractions. The temperature dependence of the magnetic susceptibility is investigated for the coarse fraction at low temperatures. The magnetic susceptibility is shown to drastically decrease below -80°C because of the mechanical blocking of particles.