Most people think of magnets as a solids. But, think again. A "liquid" form of magnet exists.
Ferrofluids contain magnetic particles in a liquid carrier, and act like a "liquid magnet." Ferrofluids do not clump together to form solids because of a surfactant, which coats the magnetic particles. The surfactant overcomes the magnetic forces between the particles and keeps the solution a liquid. A ferrofluid is primarily made of a liquid carrier, and contains relatively small amounts of magnetic particles and surfactant. Depending on the ratio of liquid carrier: magnetic particles: surfactant, ferrofluids range in viscosity and magnetization.
How do ferrofluids work?
When a magnetic field is applied to a ferrofluid the magnetic particles quickly align themselves along the magnetic field lines. Ferrofluids can be precisely positioned and manipulated by an external magnetic field. When a magnetic field is not present, the particles of the fluid are randomly distributed in no particular arrangement.
How are ferrofluids used?
Ferrofluids are applied in a variety of ways. Some ferrofluids are used as adhesives, particularly in the speaker industry. In the computer world, ferrofluids act as lubricants. For machine tools, ferrofluids come in the form of a liquid spray. Ferrofluids can also plate and protectively seal materials from the atmosphere and harmful contaminants. When correctly used, a ferrofluid can improve a product's performance.