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About this Article
Written by: Andrew Su
Written on: March 11th, 2011
Tags: energy & sustainability, material science, mechanical engineering
Thumbnail by: Clarence Risher/Wikimedia Commons
About the Author
Andrew was a senior majoring in Mechanical Engineering. Born and raised in San Jose, CA, Andrew can be found playing sports or video games in his free time.
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Volume XIV Issue I > The World’s Most Attractive Magnet that is not Attracting Attention
Invented in 1983, the neodymium magnet, though not well-known, is the world’s most powerful permanent magnet. Composed of approximately 70% iron, 5% boron, and 25% neodymium, neodymium magnets are utilized in electric motors, smart phones, hard drives, headphones, speakers, and many more applications. Compared with its predecessor, the Samarium Cobalt magnet, it is 1.5 to 2 times stronger with less density. Recently, China, the biggest producer of neodymium, has limited exports, causing concerns of shortages. This has caused resurgence in domestic mining and raised possibilities of reduced dependence on foreign imports, hopefully attracting attention to limited resources.

Introduction

A modern-day CEO can be found cruising through town in his hybrid vehicle, typing away on his smart phone while listening to music through his headphones. All of the items he utilizes contain one common element: the neodymium magnet. The neodymium magnet was invented in 1983 [21] but has not received much attention. Even though these magnets are a crucial part of electronics today, many people have no idea what they are or what their purpose is. Invented and developed by General Motors and Sumitomo Special Metals, neodymium magnets, or NIB magnets, are made up of 70% iron, 5% boron, and 25% neodymium [2]. The key ingredient in this compound is the rare-earth metal neodymium, its namesake. Together, these three elements form the strongest type of permanent magnet known to man. The magnets are strong enough to hurtle through the air and break fingers. However, despite their inherent dangers, utilized properly, neodymium magnets can be extremely useful to society.

History

The neodymium (or neo) magnet was created because the previous industry standard of the Samarium Cobalt (SmCo) magnet was becoming too expensive. A more cost-efficient magnet was needed. Neo magnets were simultaneously discovered and created in 1983 by General Motors and Sumitomo Special Metals [1]. The two companies utilized different processes in creating the magnet. General Motors created them in a powder-bonded form while Sumitomo made them in a sintered form. These two different methods of production resulted in slightly varied properties for the magnets, with the sintered form exhibiting marginally stronger magnetic properties.
Prior to the Samarium Cobalt magnet, the standard was the Alnico alloy combination magnet, or Aluminum-Nickel-Coba​lt. This alloy magnet was used until the 1970s, when rare earth metals began making their way into the magnet industry. Although termed a “rare earth metal” based on its location on the periodic table of elements, neodymium exists plentifully on Earth’s crust. In fact, it is uncommon for a modern electronic device to lack a Neo magnet. The “permanent magnet” property does not mean that it will be magnetized until the end of time. Rather, this phrase is used to describe a piece of metal that is naturally magnetized and loses its magnetism at an extremely slow rate. Once the magnetism is gone, it can not be re-magnetized. On the other hand, a non-permanent magnet can be re-magnetized infinitely, though the magnetic properties will not last for a long duration.