Permanent magnets are magnets that do not have the ability to maintain magnetism for a long time under the action of an external magnetic field, they are widely used in a variety of electronic products, motors, electrical appliances, speakers, security, toys and other fields, today to introduce some of the characteristics of permanent magnets.
What are the key characteristics of permanent magnets?
The key characteristics of permanent magnets include remanent magnetism, coercivity, maximum magnetic energy product, Curie temperature, corrosion resistance, mechanical properties, permeability, etc. The following is a brief introduction to these characteristics to give you an understanding.
Remanence (Br): Remanence is the magnetic induction (B) that a permanent magnet retains after the external magnetic field has been removed. The higher the remanence, the stronger the permanent magnet's ability to retain its magnetism.
Coercivity (Hc): Coercivity is the amount of reverse magnetic field that needs to be applied to reduce the magnetization strength (M) of a permanent magnet to zero after it has been magnetized to saturation. A high coercivity indicates that the magnet is able to resist the reverse action of an external magnetic field and remain magnetic and not easily demagnetized.
Maximum Magnetic Energy Product (BHmax or (BH)max): The magnetic energy product is the maximum magnetic energy density (BHmax) of a permanent magnet and is often used to measure the energy storage capacity of a magnet. A larger magnetic energy product indicates that the magnet can provide a stronger magnetic field.
Curie temperature: The magnetic properties of permanent magnets change with temperature. Different permanent magnetic materials have different Curie temperatures, above which the magnetic properties will be significantly reduced or even disappear.
Magnetic Permeability: Magnetic permeability is the degree to which a material responds to a magnetic field. Permanent magnets typically have a low permeability because their primary role is to generate rather than conduct magnetic fields.
Thermal Stability: Thermal stability refers to the ability of a permanent magnet to maintain its magnetic properties at different temperatures. Highly thermally stable magnets show less fluctuation in performance as the temperature changes.
Corrosion Resistance: The corrosion resistance of permanent magnets is important for applications in wet or chemically corrosive environments. Some permanent magnet materials require coatings or plating to improve their corrosion resistance.
Typical Characteristic Parameter Data for Various Permanent Magnet Materials
Permanent Magnet Material | (BH)max | Hcj | Rev Temp Coeff | Max Working Temp | Corrosion |
SmCo5 | 18-25 | 16-25 | -0.045 | 200-250 | Excellent |
Sm2Co17 | 25-32 | 10-32 | -0.03 | 300-350 | Excellent |
NdFeB | 28-52 | 10-25 | -0.12 | 80-220 | Poor |
Ferrite | 3.0-4.5 | 3.0-4.5 | -0.19 | 150-250 | Excellent |
ALNICO | 5.0-10 | 0.6-1.8 | -0.03 | 450-500 | Fair |
The cost of different permanent magnet materials varies greatly, when choosing, you need to weigh the performance and cost, if you need help, you can send us an email or online message.
Typical permanent magnet materials;
Rare earth powerful neodymium - Rare Earth Neodymium Magnets
Corrosion-resistant low-cost ferrite without plating - Sintered Ferrite (Ceramic) Magnets
High temperature and high cost samarium cobalt - Samarium Cobalt (smco) Magnets
Other related articles;
Temperature coefficient and characteristic curve of neodymium magnets
Temperature Characteristics and Coefficients of Ferrite Magnets