Magnetic materials are a kind of functional materials that are ancient and widely used. People had known and made use of magnetism, as early as 3000 years before. For example, in ancient China, people used natural magnets as compasses.
Basic Information
Modern magnetic materials have been widely used in people’s life. Permanent magnets can be used as motors, iron cores of transformers, magnetic optical disks and floppy disks of storages. Magnetic materials are closely related to information, automation, national defense and national economy.
In general, magnetic materials refer to materials composed of iron, cobalt, nickel and other alloys that can directly or indirectly produce magnetism.
Introduction
Experiments show that any materials can more or less be magnetized under outer magnetic field. The only difference is magnetization degree. According to features show in outer magnetic filed, materials can be classified into four kinds including paramagnetic materials, diamagnetic materials, ferromagnetic materials and anti-magnetic materials.
According to Molecular Current Hypothesis, materials manifest generally similar features in magnetic field, but features of materials have large differences under outer magnetic filed, which reflects limitations of Molecular Current Hypothesis. In fact, micro structures of various materials are different, which leads to variance between magnetism of materials.
Paramagnetic materials and antimagnetic materials are called weakly magnetic materials and ferromagnetic materials called strong permanent magnet materials .
Usually, magnetic materials refer to strong magnetic materials.
Based on difficulties of demagnetization, magnetic materials can be divided in soft magnetic materials and hard magnetic materials.
Materials that are easily demagnetized are called soft magnetic materials. On the contrary, materials are called hard magnetic materials.
Generally speaking, soft magnetic materials have low residual magnetism and the hard ones have high residual materials.
Application
Magnetic materials are widely used in production, life and national defense. For example, there are various permanent magnet motors and transformers in electrical power technology; magnetic assembly and electronic microwave tubes in electric technology; filters and sensitizers in communication technology; magnetic mines, magnetic cannons in national defense; various kinds of household appliances.
In addition, magnetic materials are widely applied to mining detection, ocean detection, information, energy, and biology and space technology.
China Rare Earth Magnet Limited
Tags: Permanent Magnet, Magnetic Materials
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