Everything You Need to Know About Rare Earth Magnets
Do you want to know about rare earth magnets, huh? Well, you've come to the right place! Stanford Magnets is the magnet expert, so if you have a question that's not answered below, email us and we'll answer it!
Rare Earth Magnets
What are rare earth magnets?
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials and attracts or repels other magnets.
A permanent rare earth magnet is one made from a material that stays magnetized. An example is a magnet used to hold notes on a refrigerator door.
Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic. These include iron, nickel, cobalt, some rare earth metals, some of their alloys (e.g. Alnico), and some naturally occurring minerals such as lodestone. Although ferromagnetic materials are the only ones with an attraction strong enough to a magnet to be commonly considered “magnetic”, all other substances respond weakly to a magnetic field, by one of several other types of magnetism.
An electromagnet is made from a coil of wire that acts as a magnet when an electric current passes through it but stops being a magnet when the current stops.
What are the four main types of rare earth magnets?
There are many kinds of magnets, which are generally divided into two categories: a permanent magnet and a soft magnet. The permanent magnet is divided into four categories:
1. Ferrite magnet: its main raw materials include BaFe12O19 and SrFe12O19. It is a brittle material with a hard texture. Ferrite magnet has been widely used because of its good temperature resistance, low price, and moderate performance.
2. NdFeB magnet: Nd-Fe-B is the most commercially available magnet, known as the magnet king, with extremely high magnetic properties, and its BHmax is more than 10 times higher than that of ferrite. Its mechanical properties are quite good. The working temperature can reach up to 200 degrees Celsius.
Moreover, its texture is hard, its performance is stable, and its cost performance is very good, so its application is extremely extensive. However, because of its strong chemical activity, the surface layer must be treated.
3. Samarium cobalt magnet: (SmCo) is divided into SmCo5 and Sm2Co17 according to their components. Because of the high price of SM co-material, the development of SmCo is limited. SmCo magnets, as rare earth permanent magnets, not only have high magnetic energy product (14-28MGOe), reliable coercivity, and good temperature characteristics. Compared with NdFeB magnets, the samarium cobalt magnet is more suitable for working in a high-temperature environment.
4. AlNiCo magnet: AlNiCo is an alloy composed of Al, Ni, Co, Fe, and other trace metal elements. The casting process can be made into different sizes and shapes, with good workability. The cast aluminum nickel cobalt permanent magnet has the lowest reversible temperature coefficient, and its working temperature can be as high as 600 degrees Celsius. Al Ni Co permanent magnet products are widely used in various instruments and other applications.
Which magnets are the strongest?
Rare earth magnets (Neodymium and Samarium Cobalt) are the strongest. Even a neodymium magnet the size of a pencil eraser cannot be pulled off your refrigerator by hand.
What are the coatings for neodymium magnets?
We use the following coatings on our neodymium magnets:
Nickel (Ni-Cu-Ni)
It is the most common plating. Ni-Cu-Ni is a durable 3-layer (nickel, copper, nickel coating). Great for indoor use. They may be used outdoors if protected from rain and humidity. Good abrasion resistance.
Gold-coating (Ni-Cu-Ni-Au)
Gold-coating has high corrosion resistance and is conductive. It is usually coated with a base layer of Nickel, and copper, to bring out the natural shine of the gold. It works very well in water applications. The gold layer is very but still adds some cost to the magnet.
Chrome (Ni-Cu-Ni-Cr)
The chrome has a better resistance against rubbing and pressure, that’s why we use this coating for our sphere magnets, its color is dull, and grey-metallic.
Copper (Ni-Cu)
Its color is shiny brown-red-gold. The color may change over time due to oxidation (darkening, spots). The copper-colored surface rubs off with frequent use (similar to gold-coated magnets) and is therefore suitable for decorative purposes only.
Epoxy resin (Ni-Cu-Ni-Epoxy)
Black Epoxy plating consists of 3 layers Nickel, Copper, and Epoxy exposed as the top layer. It is great for outdoor applications.
Rubber
Rubber coated neodymium magnets give great durability and high friction. The rubber coating acts as a protection for the Neodymium Magnet against chipping and exposure to liquids.
What magnets are used in everyday life?
Rare earth magnets including neodymium magnets play a significant role in a wide range of devices including simple toys, computers, credit cards, MRI machines, and business equipment. There are:
Health and Medicine
Magnets are found in some commonly used medical equipment such as Magnetic Resonance Imaging machines. MRIs use powerful magnetic fields to generate a radar-like radio signal from inside the body, using the signal to create a clear, detailed picture of bones, organs, and other tissue. An MRI magnet is very strong – thousands of times more powerful than common kitchen magnets. Another medical use for magnets is for treating cancer.
Computers and Electronics
Many computers use magnets to store data on hard drives. Magnets alter the direction of magnetic material on a hard disk in segments that then represent computer data. Later, computers read the direction of each segment of the magnetic material to “read” the data. The small speakers found in computers, televisions, and radios also use magnets; inside the speaker, a wire coil and magnet converts electronic signals into sound vibrations.
Electric Power and Other Industries
Magnets offer many benefits to the industrial world. Magnets in electric generators turn mechanical energy into electricity, while some motors use magnets to convert electricity back into mechanical work.
How to choose the right magnet?
I remember the first time I ever tried to buy magnets. It wasn't from a wargaming website. I had the hardest time knowing which size to get. We sell strong rare earth magnets that you can use for almost any purpose, including magnetizing your miniatures. With that experience in mind, we have created this short guide to choosing the right magnets:
Where to buy rare earth magnets locally?
Stanford Magnets is a company that specializes in manufacturing and offering magnetic materials in the USA, our products business range includes: NdFeB magnets, ferrite magnets, AlNiCo magnets, SmCo magnets, plastic magnets, rubber magnet, etc., the quality has gained customer consistent high praise.
How is the rare earth magnet made?
Rare earth permanent magnet material is divided into: SmCo permanent magnet and NdFeB permanent magnet. Rare earth permanent magnet materials are made by a powder metallurgy process.
How to safely use powerful magnets?
Powerful magnets should be used in the process to ensure that the workplace is clean. Otherwise, it is easy to adsorb small magnetic particles such as iron chips affect the use. For small specifications, attention should be paid to avoid knocking and breaking, and for large specifications, more attention should be paid to personal safety and protection. High-strength magnets should be kept ventilated and dry in the room when they are stored. Otherwise, the wet environment will easily cause the magnets to rust.
Conclusion
Thank you for reading our article and we hope it can help you to have a better understanding of the rare earth magnets. If you want to know more about rare earth magnets or other magnets, you can visit Stanford Magnets for more information.
Stanford Magnets has been involved in R&D, manufacturing, and sales of permanent magnets since the 1990s and provides customers with high-quality rare earth permanent magnetic products such as neodymium magnets, and other non-rare earth permanent magnets.
