Sintered Alnico Magnets

Sintered Alnico magnets are among the oldest and most established forms of permanent magnets, widely used in various industrial applications. These magnets are known for their high temperature stability, good corrosion resistance, and cost-effective production process.

The sintering process is ideal for large volume production of AlNiCos, and the resulting magnets have stronger mechanical properties than cast magnets. They are mostly suited for applications that require short magnets. The production of sintered AlNiCo magnets passes through milling, sintering, pressing, cooling, and magnetization processes.

Milling: The first step is usually to grind the metals or raw elements into fine powder or tiny particles, which are then pressed under tonnes of pressure in a die that closely resembles the magnet's desired shape.

Sintering: The pressed material is sintered in a furnace in a hydrogen atmosphere at a very high temperature to fuse all the pressed particles into one magnet.

Cooling: The red hot material is cooled either in the presence of an external magnetic (to produce anisotropic magnets) or in the absence of an external magnetic field (to produce isotropic without a preferential direction of magnetism).

Pressing: Although sintered Alnico magnets do not require further machining, you can still subject them to further processing to achieve the desired magnet shape.

Magnetizing: The raw magnetic material is finally magnetized with a solenoid magnetizer that generates the necessary electrical pulse that fully magnetizes the magnets.

Key Properties

High Magnetic Strength: Alnico magnets exhibit excellent magnetic properties, providing high magnetic flux density.

Thermal Stability: One of the standout features of Alnico magnets is their ability to maintain magnetic performance at elevated temperatures. They can operate efficiently at temperatures up to 550°C (1022°F).

Corrosion Resistance: While Alnico is not as corrosion-resistant as some rare-earth magnets, its resilience in harsh environments is still impressive.

Hardness and Mechanical Strength: Sintered Alnico magnets are typically harder than cast Alnico, but they are also more brittle, requiring care during handling and installation.

Cost Efficiency: Due to the sintering process, these magnets are often more cost-effective for high-volume production.

 

 

product key technologies

02.

Disadvantages:

Lower coercivity: Alnico magnets are more susceptible to demagnetization compared to rare-earth magnets like NdFeB (Neodymium).

Brittle nature: Care must be taken during machining and handling to prevent fractures or chips.

01.

Advantages:

High temperature stability: Can function at temperatures where other magnets fail.

Good corrosion resistance: Compared to other materials, especially in marine or humid environments.

Cost-effective for small magnets: Especially when tight tolerances are required.

Cast magnets Alnico are used in a wide range of industries due to their robust magnetic properties and stability:

Electronics and Sensors: They are commonly used in sensitive measuring devices, such as magnetometers, because of their stable magnetic field.

Motors and Generators: Alnico magnets are found in various types of electric motors and generators, where their ability to withstand high temperatures is crucial.

Loudspeakers: Alnico magnets are preferred in high-end loudspeakers due to their ability to produce a consistent and high-quality sound.

While both sintered and cast Alnico magnets share similar magnetic properties, the manufacturing processes create some important distinctions:

Tolerances: Sintered Alnico magnets can achieve tighter dimensional tolerances due to the powdered metallurgy process, making them ideal for intricate designs.

Grain Structure: Sintered magnets tend to have a more uniform grain structure, which may slightly affect magnetic performance in some applications.

Cost: Sintered Alnico magnets are often more economical for smaller magnets or when high-volume production is required, while cast Alnico is preferable for larger magnets due to its greater magnetic output per volume.

Hot Tags: sintered alnico magnets, China sintered alnico magnets manufacturers, suppliers, factory, magnet for photography, magnet for education, bonded neodymium magnet for washing machines, neodymium magnet, bonded neodymium magnet for hair dryers, magnetic game