Magnet is generally thought of to be in solid state by most of the people but this is not true. However, magnets are generally used in their solid state for several applications but magnets can even be in liquid state. Ferrofluid is a substance that if magnetized in a strong magnetic field, becomes a magnet. The properties of this substance vary with the environment. Ferrofluids are generally classified as paramagnets because they do not hold magnetic properties when external magnetic field is withdrawn.
Iron is the main constituent of ferrofluids. Other common particles are magnetite and hematite. This substance acts as a magnet under thermal agitation and when the right environment is available. Ferrofluids are suspensions where solid particles of metals are suspended in the liquid. There are various applications of ferrofluids because of their ability to change their phase as needed. They are generally used as lubricants and sealants. The other fact of ferrorfluids is that the solid particles that are present in the fluid do not come together or separate even if strong magnetic field is applied.
Ferrofluids, as said earlier are useful for various applications in industries and businesses. They are used as liquid seals for sealing the gap around hard disk shafts. They are used in machines because of their friction reducing capabilities. Diseases like cancer are being detected and treated with the help of these fluids. Their other properties are exploited for use in loudspeakers as well, for reducing the heat.
Ferrofluids are also used in art works. In various art and science museums, they are used along with other magnets to create a fountain like flow. These fluids are also used on desks and shelves that display them in suspension solutions. They can also be found easily in offices and homes as a piece of décor.
When ferrofluid is bought in the vicinity of a strong magnet, it tends to stand up at attention thus creating peaks and valleys that look black and shiny. This is an effect that is produced because of their tendency to react to magnetic field and is named as field instability. The peaks and valleys that are developed have varying degree of magnetism. Peaks have the strongest magnetic intensity while valleys have the weakest.
Ferrofluids are also used in electrical transformers. These transformers are liquid-filled. The dielectric and thermal benefits of ferrofluids make them suitable for use within these transformers. These fluids help is cooling the transformer by circulating within the transformer windings. The other use of ferrofluids is for increasing the capacity of the transformers. They are being exploited to make smaller and efficient transformers and for extending the load- capacity of existing ones. They are also used in sensors and switches.
Fluidic magnets, typically constructed using ferrofluid, are found in many household and electrical products. Understanding what a liquid magnet is and how it works is the first step to understanding why it is used in many products. Liquid magnets are constructed of a colloidal substance on the Nano scale, which has been suspended in a protective fluidic carrier; typically used is water or other organic solvents. A colloidal substance, in this case, liquid iron, is one that is suspended on a microscopic scale within its protective liquid evenly. This fluidic iron uses a surfactant to stop it from binding with other like particles.
What Ferrofluid Contains and its Many Uses?
In other words, ferrofluid is simply surfactant coated liquid iron suspended in a fluid. In many countries, art makers use it in their creations and it is used in decorative and functional magnets as well. Most ferrofluids contain 5% solid matter, 10% nonbinding agents, and 85% carrier fluids, using a volume measure. Fluidic magnets retain a shape only if a magnet force is present. If there is no magnetic field present, then it takes the shape of the container holding the liquid, the same way water does.
Some of the products that use ferrofluid include many electronics such as computer hard disk drive seals and audio speakers; in air craft to absorb some radar waves; in altitude control systems of NASA shuttles and, most notably, in magnetic resonance systems otherwise known as MRI scanners in the medical field. The medical field is also experimenting with the fluidic magnet for use in some cancer treatments, such as magnetic hyperthermia. In each instance the ferrofluid is used, a magnet changes the force of the fluid so it performs a different task.
Making Ferrofluids
Making ferrofluid is a simple task and one that anyone can complete at home. The materials needed include a jar or beaker to hold the contents, magnetic ink and a light lubricating oil or vegetable oil. The best magnetic ink to use is the powdered type used in character recognition printing. Simply pour about a cup of oil into the container and add the magnetic ink to it in little amounts. After each addition of powdered ink, stir the mixture until it is completely wet. Remember that because it is a suspension, the ink will not dissolve in the oil, it will simply become wet. Continue adding magnetic ink until an oozing liquid is achieved. If the mixture is too thin, the magnetic field will not work properly. After experimenting with the consistency, take a hard magnet and hover it over the ferrofluid mixture in the container. If the correct consistency is achieved, the ferrofluid should raise into jagged peaks or other shapes.
