The word – magnet is always related the concept of attraction. In the physical world, it’s a force where two or more objects pulling towards each other, which we refer to as magnetic force. Abstractly, magnet can be a person, a thing or a place that is attractive to a person. However, just like a thing can lose its shine or a person his charm with time, magnets can lose its magnetism. That’s where permanent magnets make a difference.
By definition, a permanent magnet is a magnet that never loses its magnetic field. The first permanent magnet in history is called a loadstone. It is a naturally magnetized rock mainly composed of Fe3O4.
In the modern history, the first permanent magnet ever developed and commercially used is called AlNiCo. AlNiCo was developed in the early 1930s and was then used in military electronic applications during World War II. AlNiCo magnets are divided into cast AlNiCo and sintered AlNiCo. Alnico offers high magnetic field. But it has a low coercive force, which mean it can be easily demagnetized.
In the 1960s, hard ferrite or ceramic magnet was developed and quickly gained popularity in the world industry. It is a low-cost permanent magnet material made primarily of strontium carbonate and iron oxide (Fe2O3). Due to its good resistance to demagnetization and excellent corrosion resistance, ceramic magnets gained its market very quickly. Nowadays, if measuring by weight, over 70% of the magnets commercially used are hard ferrite/ceramic magnets.
A few years later, something called rare earth magnet was developed. It was Samarium-Cobalt that opened the era of rare earth magnets. This permanent magnet material has two series: SmCo5 and Sm2Co17. In addition to their excellent magnetic strength, they can withstand high temperature.
In the early 1980s, a brand-new rare-earth magnet called neodymium magnet (NdFeB) was independently developed by Japanese and American. NdFeB magnet exhibits a much stronger magnetic strength than any previous permanent magnet material. It has enabled miniaturization in design and introduced more possibilities in modern technology.
About Tengye: Tengye Magnetic supplies finest permanent magnet materials and custom magnetic assemblies to world industry. We work closely with our customer from designing stage to mass production.