Wonders of Neodymium Magnets
Many of us would still remember our academic lessons which mentioned that magnets can be classified broadly in 2 categories namely temporary and permanent.
We also learnt a few tricks on creating temporary magnets on our own during the science or physics class making this category a preferred one for the newbie. However, the magnets that play an important role in our lives are mostly permanent magnets. Permanent magnets differ from temporary in the way they retain their magnetism or the magnetic field after being magnetized under a proper application. Temporary magnets, on the other hand, cannot retain magnetism for very long on their own.
Different types of permanent magnets are available in the market. The list includes ceramic magnets, flexible magnets, neodymium magnets, samarium magnets and alnico magnets. Permanent magnets usually possess high coercive force which enables them to maintain their magnetic field. Some other properties that influence the magnetism of permanent magnets include residual induction, max energy product and max service temperature. All these parameters are directly proportional to the magnetic field of a permanent magnet.
Of the type of permanent magnets mentioned above, neodymium magnets and samarium magnets belong to the category of rare earth magnets. This is due to the fact that these magnets for sale are produced from using rare earth elements like neodymium and samarium which find their roots in rare earth alloys. Neodymium magnets are one of the most powerful magnets available on the planet. Their composition includes Iron(Fe), Boron(B) and Neodymium(Nd). This compound was discovered jointly by GM, Sumitomo Special Metals and China Academy of Science. The joint effort of research was carried out to find a replacement of SmCo magnets which were also classified as permanent magnets. The downside of SmCo permanent magnets was high material cost. Neodymium magnets are the strongest magnets when compared with other types of magnets.
Neodymium magnets are manufactured using two principal routes namely sintered process and bonded process. After the invention GM was focused on industrialization of bonded neodymium magnets while Sumitomo concentrated on the sintered version of neodymium magnets. As I write this article, yearly production of sintered neodymium magnets is between 45k to 50k tons. Bonded neodymium magnets on the other hand offer less residual induction and are produced to a number of 5.5k tons per year. Sintered magnets are largely manufactured in China and Japan.
Neodymium magnets are indispensable due to characteristics like exceptionally high magnetic power and strong holding strength. These magnets find their applications multitude of domestic as well as professional daily use devices. Neodymium magnets are used in computer hard drives, MRI scan machines, modern-day guitars, magnetic bearings and magnetic couplings. To add to the list are magnetic motors of various types. Magnetic motors include stepper motors, drive motors for electric/hybrid vehicles, power steering, servo motors, electronic motors used in myriad of electrical appliances and electronic devices. They are also used in cameras and watches.
While neodymium magnets are the most powerful magnets on earth, they are also hard and brittle. Depending on the application they are coolant served to absorb heating in the absence of which these magnets could crack or chip. Neodymium magnets are easily corrupted in damp or humid work environments and surface protection is recommended. At high temperatures, their magnetic properties could be altered or lost. However, neodymium magnets turn out to be very stable magnets within wide range of operating temperature and hence they are widely used in various industries.