Neodymium - iron - boron, simply speaking, is a kind of magnet. What's different from the magnets we see in daily life is that it is known as the "King of Magnets" because of its excellent magnetic properties. Neodymium - iron - boron contains a large amount of the rare - earth element neodymium, as well as iron and boron. It is hard and brittle. Because its surface is very easy to be oxidized and corroded, neodymium - iron - boron must be given a surface - coating treatment. Surface chemical passivation is one of the excellent treatment methods.
As a kind of rare - earth permanent - magnet material, neodymium - iron - boron has an extremely high magnetic energy product and coercivity. At the same time, the advantage of high - energy density enables neodymium - iron - boron permanent - magnet materials to be widely used in modern industries and electronic technologies, making it possible to miniaturize, lighten, and thin devices such as instruments and meters, electro - acoustic motors, and magnetic separation and magnetization equipment. The advantages of neodymium - iron - boron are its high cost - performance ratio and excellent mechanical properties. The disadvantages are its low working temperature, poor temperature characteristics, and easy pulverization and corrosion. It must be improved by adjusting its chemical composition and using surface - treatment methods to meet the requirements of practical use. As a relatively new result of the development of rare - earth permanent - magnet materials, neodymium - iron - boron magnetic materials are known as the "King of Magnets" because of their excellent magnetic properties. Neodymium - iron - boron magnetic materials are alloys of praseodymium - neodymium metals, ferro - boron, etc. They are also called magnetic steel.
Ferrite is a kind of ferromagnetic metal oxide. In terms of electrical characteristics, the resistivity of ferrite is much larger than that of metal and alloy magnetic materials, and it also has relatively high dielectric properties. The magnetic properties of ferrite are also manifested in its high magnetic permeability at high frequencies. Therefore, ferrite has become a non - metallic magnetic material that is widely used in the field of high - frequency weak - current. Because the magnetic energy stored per unit volume of ferrite is low and the saturation magnetization is also low (usually only 1/3 - 1/5 of that of pure iron), its use in the field of low - frequency strong - current and high - power applications that require a relatively high magnetic - energy density is limited.
