Magnet Alnico Bars and Keeper

Alnico Bar Magnets with Keepers are high-performance permanent magnets widely used in educational and industrial settings for their reliability and stability. Composed of an alloy of Aluminum (Al), Nickel (Ni), and Cobalt (Co), they are significantly stronger than standard steel magnets and are designed to hold their magnetic charge for many years.

The Role of the "Keeper"

A keeper is a soft iron or steel bar placed across the poles of a magnet when it is not in use. It is critical for Alnico magnets because:

• Magnetic Circuit Completion: It closes the magnetic loop, preventing the magnetic field from leaking and dissipating over time.
• Preservation: Without a keeper, Alnico magnets can slowly self-demagnetize due to their low resistance to external magnetic fields (low coercivity).
• Safety: It keeps the magnetic field contained, preventing the magnet from accidentally attracting nearby metal objects or damaging sensitive electronics.

Common Educational Experiments

• Magnetic Field Mapping: Using iron filings to see the invisible flux lines extending between the poles.
• Magnetic Induction: Demonstrating how a permanent magnet can temporarily magnetize other metal objects like paperclips.
• Polarity Interaction: Investigating the rule that "like poles repel and opposite poles attract."