Without physically touching them, magnets create a field that pulls or repels other materials. Since at least 500 AD, natural magnets have been utilized and studied. However, new classes of artificial magnets were created in the 1980s. Anything can be done with magnets, from pinning the grocery list to the fridge to creating electricity for maglev trains to hover.
The most prevalent kind of magnets are permanent magnets. Although some permanent magnets are susceptible to high temperatures or abrupt drops in temperature, they are so-called because once magnetized, they remain at least somewhat magnetized. At a certain temperature, some permanent magnets start to weaken, and at very high temperatures, they eventually demagnetize.
Permanent magnet types
The magnets that hang on our refrigerator doors and other permanent magnets are the ones we are most accustomed to. Once magnetized, they acquire a certain amount of magnetism and are therefore permanent. We’ll see that there are differences between the various kinds of permanent magnets in terms of things like whether or not they demagnetize, how strong they can be, how their strength varies with temperature, etc. It is accompanied by a variety of features. Any shape you can think of can be created using permanent magnets. They can be shaped into discs, rectangles, multi-fingered rings, horseshoes, rings, donuts, round sticks, rectangular sticks, and other unique shapes. Some require grinding to reach their final dimensions after being poured into a mold. Others begin as powder that has been sintered, pressure-bonded, or pressed into a mold. In order to create permanent magnets, four different materials are used: ceramic or ferrite, alnico, neodymium iron boron (NdFeB), and samarium cobalt (SmCo). The most widely used permanent magnets on the market, according to Magnet Man, are ceramic or ferrite magnets. These flexible magnets, like the business card-shaped magnets that are frequently adhered to the front of refrigerators, are made by combining a flexible binder with magnetic powder. Alnico magnets are composed of aluminum, nickel, and cobalt and were first created in the 1940s. Although it operates at a higher temperature than other permanent magnets, this type of magnet is easily demagnetized by other magnets or dropping objects. The two strongest permanent magnets are rare earth magnets, neodymium iron boron (NdFeB) and samarium cobalt (SmCo). These kinds of magnets, according to Magnet Man, were created in the 1970s and 1980s using rare earths, or the elements in the periodic table’s lanthanide series.
The typical design of an electromagnet is a coil of wire wound around an iron metal core. These substances produce almost no magnetic field when not in contact with an electric current. However, a magnetic field is created when an electric current flows through the wire until the current is cut off. In contrast to permanent magnets, an electromagnet’s magnetic field’s strength can be modified by altering the amount of current passing through the wire. Reversing the direction of the electric current can also alter the polarity of the magnet.
When in a strong magnetic field, temporary magnets behave like permanent magnets, but they lose their magnetism when the magnetic field is lost. When exposed to a magnetic field, soft iron objects such as paper clips, metal nails, and other items can become magnetic and act as temporary magnets. A second paper clip may be hung from the first one if it hangs from the magnet. When the magnetic field is removed, the object loses its magnetic properties, and when the paper clips are taken out of the magnetic field’s original source, they cease to function as magnets.
How do magnets get made?
Making a magnet like the Neodymium Iron Boron magnet (Nd2Fe14B or Nd15Fe77B8) involves six basic steps.
It is made of an alloy of iron, boron, and neodymium. To create an alloy of Nd2Fe14B, approximately 0.014 pounds of boron and 0.369 pounds of neodymium are needed for every pound of iron. To melt this, the temperature must be raised above 1538 degrees. It’s crucial to thoroughly combine the ingredients for a cake as well as the ingredients with the iron.
2. A powdered version of the alloy is created. The alloy needs to be ground or ground into a very fine powder after cooling.
3. A mold is filled with the powder. The powder is poured into a disc-shaped mold, but it is also positioned deeper than the final piece’s thickness. The powder is then compressed under pressure of several hundred pounds to form a solid disc. A sintered magnet is created when heat is used to help particles fuse together. It can occasionally be held together by an adhesive, in which case it is referred to as a bonded magnet. specific final size The disc needs to be coated with a thin nickel film to increase the magnet’s corrosion resistance; you might need to grind the piece to get to the number 4. Epoxy, zinc, or a gold film may also be applied occasionally. Since nickel doesn’t oxidize like iron does, magnets interact well with it.
5. It has a magnetized magnet. It will be placed in a magnetizing apparatus with a wire coil through which a strong current pulse is briefly passed. To prevent hitting anything or anyone, the magnet needs to be secured in place. It actually magnetizes its magnet in a thousandth of a second.
6. To create the ideal product, engineers frequently need special magnetization configurations or shapes. They consult the magnet manufacturer to determine the most effective way to create the required magnet. That explains why the magnets in the catalogs come in so many different sizes and shapes.