The Applications and Properties of Ferrofluids Essay -- Magnets Magnet

Missing Figures The purpose of this paper is to describe and explain the properties of ferrofluids. Imagine the applications of a liquid substance that can be controlled at a distance by a magnetic force. To create such a liquid is not as simple as liquefying a magnetic solid. Magnetic solids lose their magnetic properties at the temperature above the Curie temperature of the substance. At that temperature thermal energy overwhelms the tendency of the electrons to align in regions of similar spins. The Curie temperature is well below the melting point of all normal magnetic solids. (Verschuur, 1993) Ferrofluids overcome this obstacle. They are colloidal suspension of magnetic nanoscale magnetic material in a liquid carrier. This gives the Ferrofluid the properties of normal liquids, but allows the entire liquid to be manipulated to an applied magnetic field. (Berger, 1999) In the 1960?s Stephen Pappell with NASA developed ferrofluids to address the problem of controlling fluids in the zero gravity environment of space. (Verschuur, 1993) Ferrofluids were originally used by the space program to create leak proof seals in satellites. The commercial applications were later recognized. A ferrofluid can behave as a liquid O-ring where a rotating shaft enters either a low- or high-pressure chamber. The ferrofluid is held in place by permanent magnets and form tight seals, eliminating most of the friction produced in a conventional mechanical seal. Rotating shaft seals are found in rotating anode X-ray generators and in vacuum chambers used in the semiconductor industry. Ferrofluid seals are also used in high-speed computer disk drives to eliminate harmful dust particles or other impurities that can cause the sensitive data-reading ... ...e:3YVBr1dVcRkJ:voh.chem.ucla.edu/classes/ Magnetic_fluids/pdf/ChemicalEducationArticle.pdf+surfactant+aqueous+ferrofluid&hl=en&ct=clnk&cd=2&gl=us&client=firefox-a Enzel, P., Adelman, N., Beckman, K. J., Campbell, D. J., Ellis, A.B., Lisensky, G. C., (1999) "Preparation of an Aqueous-Based Ferrofluid." J. Chem. Educ. Vol. 76, 943. Retrieved May 7, 2008, from http://mrsec.wisc.edu/Edetc/background/ferrofluid/index.html Ferrotec (2008), Ferrofluid, Retrieved May 9, 2008, from http://www.ferrotec.com/products/ferrofluid/ Nave, R. (2000). Surface Tension. HyperPhysics. Retrieved May 7, 2008, from HyperPhysics database. Verschuur, G (1993). Hidden Attraction: The Mystery and History of Magnetism. New York: Oxford University Press. Willis B, (2001), Brownian Motion, Retrieved May 7, 2008, from http://www.worsleyschool.net/science/files/brownian/motion.html