Magnetic ceramics are also called ferrites. These materials refer to composite oxide magnetic materials composed of iron ions, oxygen ions and other metal ions, and there are a few magnetic oxides that do not contain iron. According to the application, such materials can be divided into soft magnetic, hard magnetic, gyromagnetic, momentary and piezoelectric. Soft magnetic ceramic materials are currently the most diverse and widely used magnetic ceramics. They are characterized by high initial permeability, easy magnetization and easy demagnetization.

Ⅰ. Excellent performance of ferrite magnets

1. Energy saving

Ferrite magnet permanent magnet material can provide stable and lasting magnetic flux without consuming electric energy, which is one of the important means to save energy. Permanent magnet motors are typical energy-saving and low-carbon industrial products, which are widely used in various industrial transmission and rotating devices.

2. Price advantage

Ferrite permanent magnet materials are rich in resources and low in price. Its price is one tenth of that of AlNiCo magnets and one percent of that of samarium cobalt permanent magnets. It is widely used in micro motors. As the core component of downstream micro-motors, permanent magnet ferrite wet-pressed magnetic tiles are widely used in automobiles and motorcycles, household appliances, power tools and other industries. In DC motors, permanent magnet ferrite is an essential key material. A DC motor needs at least 2 pieces of permanent magnet ferrite, and it can reach dozens of pieces. High-performance wet-pressed magnetic tiles are widely used. The wet-pressed magnetic tile is the core component of the permanent magnet micro-special motor. It is generally used as a motor stator and is mainly used in various motors such as automobiles, motorcycles, home appliances, power tools and fitness equipment. Among them, automobiles, motorcycles and inverters are widely used. 

Ⅱ. Ferrite magnets are classified by use

From the perspective of the properties and uses of magnetic ceramics, it can be divided into soft magnetic, hard magnetic, gyromagnetic, piezoelectric magnetic bubble, magneto-optical and thermal magnetic ceramics.

1. Hard magnetic

Also known as magnetic ceramics, it is a kind of magnetic ceramics with large coercivity, not easy to demagnetize after magnetization, and retains magnetism for a long time. Ferrite ceramics have high magnetic properties, high magnetic induction intensity and high magnetic energy. The main ferrite ceramics mostly belong to the magnetoplumbite structure, such as Ba-ferrite, Sr-ferrite, Pb-ferrite and their complexes. In addition, Co-ferrite, which belongs to the spinel type, is also used as a hard magnetic material due to its large lattice anisotropy.

2. Magnetic bubble

Ferrite magnet bubbles are circular domains in magnetic ceramics that are perpendicular to the film. The diameter is 1~100μm and looks like a bubble, so it is vividly called a "magnetic bubble". The magnetic bubble material is a new type of magnetic storage material, and the two states of "1" and "o" of information are represented by "presence" and "absence" of "bubble". The generation, disappearance, transmission, splitting of "bubbles" and the interaction between magnetic bubbles are controlled by circuits and magnetic fields, and functions such as information storage, memory, and logic operations are realized. Magnetic bubble memory has the advantages of large capacity, small size, low power consumption and high reliability.

3. Piezomagnetism

It is a magnetic ceramic that uses magnetostriction to convert electrical energy into mechanical energy or mechanical energy into electrical energy, also known as magnetostrictive material. Ferrites in piezoelectric ferrite magnets include Ni-most n, Ni-Cu, Ni-Mg and Ni-Co ferrites, of which Ni-most n ferrites are the most widely used. Piezoelectric ferrites are mainly used in ultrasonic, underwater acoustic devices, mechanical filters and some telecommunication devices.