AlNiCo Magnets

AlNiCo permanent magnet is an alloy magnet made from Al,Ni,Co,Fe and other trace metal elements and may be produced through either sintering or casting process. The product has remarkable resistance against corrosion and high temperature, and is mainly used in certain precision instruments.

Common applications

• Magnetos
• Separators
• MRI
• Sensors
• Holding magnets
• Security systems
• Relays

Machining and tolerances

Most alnico magnets are manufactured using typical foundry casting techniques, where the molten alloy is poured into sand molds. Very small magnets, usually one ounce or less, are also produced using the press and sinter techniques. Alnico is hard and brittle (45-55 Rockwell C), and is not suitable for drilling, tapping or conventional machining operations. Close tolerances are attained by abrasive grinding and cutting. Standard tolerances for ground dimensions are +/-.005″. Tolerances for as cast dimensions vary with the actual part size. Un-ground surfaces are gray to dark brown in color but are bright metallic after grinding.

Temperature constraints and methods of magnetization

Alnico has the lowest temperature coefficient of any commercial magnet material, providing for excellent stability over a wide temperature range. A properly designed circuit using alnico magnets will have a stable flux output during temperature fluctuations. Maximum operating temperature for alnico is 950°F.

Magnetization

Alnico can be partially demagnetized if like poles of magnets are brought together. Placing individual magnets in contact with ferrous materials can also partially demagnetize them. Care must be exhibited in handling magnetized magnets. Typical alnico 5 applications require a long magnetic length to pole surface ratio (usually 4:1 or greater) to insure good magnetic performance.

Added value services

We provides in-house cutting and grinding to meet your application requirements. We also provide magnetic circuit design assistance to enable you to choose the proper material and the proper size magnet to perform the task you require.