Neodymium is an element that is soft and silvery in appearance. It is also a rare earth element, which is a category of seventeen elements of the lanthanide series on the periodic table that are naturally found together and difficult to separate from one another. They can also retain their magnetism more efficiently than magnets made from ferrous materials. Neodymium is the strongest and most reactive of all the rare earth elements, and are used in applications that require exceptionally powerful magnets. In terms of performance, cost, and size, neodymium magnets are highly recommended over other types of magnets.
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What is a Neodymium Magnet?
Neodymium magnets, or neo magnets, are made from a compound of neodymium, boron, and iron. Like all rare earth magnets, neo magnets are exceptionally resistant to demagnetization, and they have a larger strength to size ratio than other magnets. Although it costs more to manufacture neo magnets, they require significantly less volume due to their high strength to size ratio. Neo magnets are fabricated similarly to ceramic magnets. Neo magnets are made by grinding the material into powder, and then forming it into a particular shape. A magnetic field is then applied for orientation, and they are sintered until the desired density is achieved. This fabrication process enables manufacturers to make neodymium magnets in a wide range of configurations, such as blocks, rings, and discs.
Benefits of Neodymium Magnets
Neodymium magnets outdo samarium cobalt magnets in terms of cost and strength, which makes them a popular choice for so many applications. Therefore, neo magnets are used more frequently in a multitude of applications. An important factor for magnets to have in carrying out various functions is to have magnetic permanence, or the ability to retain magnetism under circumstances such as heat, electric fields, corrosion, and vibration. Applications in which magnetic permanence is highly critical include medical, automotive, and industrial equipment.
Neo Magnet Disadvantages
As powerful as their magnetic force can be, neo magnets do not hold up well against corrosion and relatively low temperatures, such as around 200 degrees Celsius (392 degrees Fahrenheit). In addition, they can easily be cracked or chipped. Therefore, neo magnets are almost always equipped with a protective metal coating made of either nickel or another strong type of metal. Samarium magnets have a significantly higher heat threshold, and are used in applications in which the heat level is higher than what neo magnets can tolerate.
In addition to a low heat threshold, there is another drawback to a neo magnet. Because of how powerfully they can be drawn to each other, neo magnets have the potential of shattering if two or more of them are too close in proximity to one another. If a neo magnet is larger than several cubic centimeters, it can pose a hazard to workers who handle them. If two of these magnets are too close, body parts can be sandwiched between them, and possibly break bone. Therefore, in utilizing larger neo magnets, safety precautions must be in place for anyone who works with or near them.
Neodymium Magnet Manufacturing Process
There are two main processes of manufacturing neo magnets. The first is classical powder metallurgy, or the sintered metal method. This process involves using a furnace to melt raw materials and mix them together, and then placing the molten material into a mold as it cools, solidifies, and takes on the mold’s shape. Rapid solidification is the process of using a melt spinning technique to create a neodymium magnet. Melt spinning is a process that quickly cools molten raw material by a wheel that is cooled internally by water or liquid nitrogen and is rotated. The liquid is then dripped onto the wheel, where it rapidly cools and solidifies.
Applications of Neo Magnets
Neo magnets are a permanent magnet, meaning that it will not lose its magnetic field regardless of the external conditions. The neo magnet is the strongest and most widely used out of all the types of magnets. Examples of applications that utilize neo magnets include DC motors, computer disc drives, microphone assemblies, magnetic fasteners, cordless tools, magnetic separators, servo motors, and linear actuators.
The demand for rare earth magnets has been on the rise in many industries and facilities due to the automotive industry beginning to explore fuel sources other than petroleum. Neo magnets are an important component in certain pieces of equipment such as wind turbines and electric motors, and the scarcity of lanthanoid ore has become a concern. Fortunately, industries such as aerospace, medical, automotive, and electronics have explored uses for rare earth magnets. Rare earth magnets could see some growth as an alternative energy source in the near future.