As the core driving force of modern technology, the performance of magnetic materials is directly related to motor efficiency, electronic device performance, and energy conversion efficiency. Understanding its key characteristics is crucial for expanding application scenarios. These characteristics mainly include magnetization, remanence, coercivity, permeability, Curie temperature, etc.
Magnetization intensity is a quantitative measure of the degree to which a material is magnetized under an external magnetic field, influenced by its composition, crystal structure, and temperature. High magnetization materials such as neodymium iron boron can significantly improve the power density of motors, and the magnetization also determines the stability of magnetic storage units.
Residual magnetism refers to the magnetic induction intensity that remains after the external magnetic field is removed from the material, and is a key indicator of permanent magnet materials. High residual magnetism ensures stable output of speaker sound signals and is also the basis for magnetic fixtures to achieve non external energy adsorption function. Residual magnetism originates from the locking of magnetic domains within the material. When the magnetic domains are aligned with the direction of the external magnetic field, after removing the magnetic field, the magnetic domains are difficult to restore their disordered state due to energy barriers, thus retaining their magnetism.
Coercivity represents the ability of materials to resist demagnetization, and high coercivity materials are more difficult to demagnetize and are suitable for permanent magnet applications; Low coercivity facilitates repeated magnetization and is suitable for soft magnetic materials. The difficulty of magnetic domain wall movement and magnetic crystal anisotropy are the main factors affecting coercivity.
Magnetic permeability describes the ability of a material to conduct magnetic lines, and high permeability materials can efficiently gather magnetic fields for use in precision sensors; Low permeability materials are used for magnetic shielding to prevent magnetic field interference.
The Curie temperature is the critical temperature at which a material loses its ferromagnetism, beyond which the material becomes paramagnetic. The Curie temperature is crucial for the stability of permanent magnets and the design of temperature sensors. The development of high-temperature resistant permanent magnets and the exploration of new materials have become challenges in material design.
In addition, magnetic energy product and temperature stability are also important indicators for measuring the performance of magnetic materials. High magnetic energy product materials such as neodymium iron boron are suitable for small and efficient motors; And temperature stability is related to the performance of materials at high temperatures.
In practical applications, the characteristics of magnetic materials need to be synergistically optimized. For example, permanent magnet motors need to have both high remanence and high coercivity, while controlling cost and weight; High frequency transformers require high magnetic permeability and low coercivity, as well as suppression of eddy current losses.
In the future, magnetic materials will develop towards high-performance, nanostructure design, intelligent materials, and green recycling, breaking through performance boundaries, reducing dependence on rare earths, achieving magnetic electric thermal multi field coupling, improving magnetic material recovery rate, and reducing environmental burden. The key characteristics of magnetic materials are like a ‘genetic code’, and every technological leap cannot be separated from precise regulation of these characteristics.