In general, magnets describe any materials that can attract ferromagnetic objects. These ferromagnetic objects include iron, nickel, cobalt, and so many others. Magnets produce magnetic fields, which are responsible for their ability to attract ferromagnetic objects. Although magnetic fields are invisible, their presence can be detected via the magnetic force they exert.
Permanent magnets are objects created from materials that have been magnetized. They are not easily demagnetized, and they can generate their magnetic field. Permanent magnets can be found all around our environment. They come in different types and have various uses.
Types of Permanent Magnet
Permanent magnets are usually grouped based on the materials from which they are made or the methods used in making them. Below are the most common types of permanent magnets.
Ferrite magnet is also known as a ceramic magnet. It is usually composed of iron oxide mixed with barium or strontium carbonate. The advantage of this type of magnet is that it is less expensive to create than most other types of magnets because the materials needed to form it are not costly. This magnet is rather brittle and has a low magnetic strength. However, it is highly resistant to corrosion. Ferrite magnet is available in grades 1,5and 8. Each grade has a different magnetic strength.
As the name implies, this type of permanent magnet is made from aluminum (Al), nickel(Ni), and cobalt(Co). However, little quantities of other elements are added when producing Alnico magnets to improve their properties. It is highly resistant to corrosion and is stable even under high temperatures. This type of permanent magnet is produced by sintering and casting. Sintering gives Alnico magnet its high mechanical strength.
Samarium Cobalt Magnet
Samarium Cobalt permanent magnet is made from samarium cobalt, which is a rare earth magnet. This magnet is highly resistant to corrosion, as well as temperatures of up to 300°C. It has a high coercive force and is used for high-energy products. Despite all of this, this type of permanent magnet is expensive and very brittle. Therefore, it is rarely used except in appliances that are subjected to high temperatures.
Neodymium Iron Boron Magnet
Despite its similarities to the samarium cobalt magnet, neodymium iron boron magnet is less resistant to corrosion except when coated. It also has less resistance to high temperatures and low mechanical strength with a range of up to 50MGOe. The material used for the production of this type of magnet is quite costly. For this reason, they are primarily used selectively.
It is composed of renin and magnetic powder. It usually has low magnetic strength and low resistance to heat. Injection-Molded magnets have physical properties that make them similar to plastics.
Flexible Magnets are similar to injection-molded magnets in that they also have a low resistance to heat and low magnetic strength. However, it is highly flexible. They are made by binding ferrite or rare-earth magnet powders in various plastic binders, such as vinyl.
Uses of Permanent Magnets
Microphones: permanent magnets are vital for the functioning of microphones. This is because microphones work based on the principle of permanent magnets. The sound from a microphone is reproduced when the movement of a coil generates an electrical signal through a magnetic field.
Permanent Magnet Motor: this is a type of motor that makes use of permanent magnets. The magnet is attached to the motor’s rotor, and when current flows through a conductor, the magnetic field through which a coil rotates is produced. In this way, electrical energy from the conductor is converted into mechanical energy.
Permanent Magnet Generator: it is also referred to as a permanent magnet alternator. It relies on the propensity of a magnet to convert mechanical energy into electrical energy. The science behind the use of permanent magnets to produce electricity is that two magnets are kept opposite to each other. The force of repulsion between both magnets causes a power-generating turbine to rotate. This then causes an armature to rotate, and the rotating armature, in turn, generates electrical energy.
Jewelry: permanent magnets are often used in the manufacture of jewelry. The attraction between magnets and ferromagnetic materials is employed in keeping jewelry tightly clasped.
Sensors: permanent magnets can be used to activate a Reed Switch sensor. A Reed Switch sensor makes use of two glass bulbs. These bulbs begin to blink when a magnetic field is present. This is because the Reed Switch closes when in contact with a magnetic field of appropriate magnitude.
Magnetic Locks: magnetic locks are usually used on emergency exits such as fire exits. A magnetic lock is not dependent on electricity. This means that the security of whatever is being locked is guaranteed with or without electricity. An advantage of a magnetic lock is that it cannot be easily tampered with because there is no opening to insert a pick or wrench. Magnetic locks vary in complexity and reliability depending on their structural design.
Magnetic Resonance Imaging: permanent magnets are also important in medicine. MRIs can be used to view the internal organs of a patient’s body without the fear of risks associated with surgery. Because of the high magnetic fields created by MRIs, it is essential not to allow ferromagnetic materials into rooms with MRI devices.
Refrigerator Magnets: refrigerator magnets usually come in different sizes and designs. They can be used to decorate the refrigerator or hold up things on the fridge like a thumbtack may be used to hold up stuff on a wall.
Screwdriving: permanent magnets may be used in a screwdriver to hold a screw in place, especially if the screw easily slips away. This makes screwdriving a whole lot easier and faster.
Permanent magnets are one of the most versatile and valuable materials in existence. Given the many high-end uses of permanent magnets, it makes perfect sense to invest in them if they are essential to or help improve your business processes.