AlNiCo Magnets:

This class of magnets is predominantly composed of aluminium, nickel, and cobalt, a combination that was first developed during the 1940s. Owing to their outstanding temperature stability, high magnetic flux density, and exceptional resistance to corrosion, these magnets continue to be a preferred choice across various industrial applications.

 

Alnico magnets are produced using either casting or sintering techniques. The casting process, in particular, offers a significant advantage, as it enables the production of highly intricate and complex shapes that are difficult to achieve with alternative magnetic materials. This versatility in manufacturing, combined with their superior performance characteristics, underpins their continued relevance in modern engineering and manufacturing environments.

Alnico materials are distinguished by their exceptional temperature stability, strong residual induction, and comparatively high energy output. These alloys are principally composed of aluminium, nickel, and cobalt.

 

Manufacturing is undertaken using either casting or sintering techniques. Cast Alnico magnets can be produced in complex geometries, such as horseshoe shapes, to meet specific design requirements. While sintered Alnico magnets exhibit marginally lower magnetic performance than their cast counterparts, they offer enhanced mechanical strength and durability, making them particularly suitable for demanding operational environments.

Cast Alnico 5 represents the most widely utilised grade among all cast Alnico magnet materials. Renowned for its reliable magnetic properties, it is extensively employed across a broad spectrum of industrial and commercial applications, including but not limited to rotating machinery, electrical meters, precision instruments, sensing equipment, and various holding solutions.

 

Due to its intrinsic hardness and brittleness, Alnico cannot be subjected to conventional machining or drilling processes. Consequently, any required holes are typically incorporated during the casting stage at the foundry. The magnets are generally cast to dimensions that are very close to their final specifications, after which they undergo precision grinding to achieve the exact tolerances demanded by the application.

Alnico is characterised by a relatively low coercive force, which means it is susceptible to demagnetisation if not managed with appropriate care. To ensure optimal performance, particularly with Alnico 5, it is recommended that the magnetic length be approximately five times the pole diameter, or its equivalent diameter. For instance, a magnet with a diameter of 0.250 inches should ideally have a length of around 1.00 inch to achieve maximum efficiency.

 

In contrast, Alnico 8 possesses a higher coercivity, enabling it to maintain its magnetic properties more effectively. As a result, this grade of Alnico can be utilised in shorter lengths and is well-suited to disc-shaped configurations.

ALNiCo Magenets - PDF

Magnetic Property Table for Cast AlNiCo

Magnetic property parameters of Sintered AlNiCo