Magnet Advice: Make the Right Choice

At SAV-Webshop, you don't just get the most powerful magnets, but also the best advice. The choice of material depends on factors such as temperature, environment, and the required strength. Use this overview to find the perfect magnet for your application.

Comparison of Magnet Materials

Neodymium (NdFeB)

Neodymium magnets are the most powerful permanent magnets currently commercially available. They are made from an alloy of Neodymium, Iron, and Boron.

• Advantages: Unprecedented pull force at a very small size.
• Disadvantages: Without coating (nickel or zinc), they will rust. Standard types lose their strength above 80°C.
• Application: Machine building, high-end audio, electric motors, and packaging.

Ferrite (Ceramic magnets)

The most widely used magnet in the world. Ferrite magnets are non-conductive, ceramic materials made of iron oxide and barium or strontium carbonate.

• Advantages: Very affordable, never rusts (even in salt water), and is resistant to temperatures up to 250°C.
• Disadvantages: Much larger volume required for the same strength as Neodymium. Brittle material.
• Application: Speakers, fridge magnets, sensors, and maritime environments.

SmCo (Samarium-Cobalt)

Samarium-cobalt magnets are rare-earth magnets that remain stable at extreme temperatures and are resistant to corrosion without coating.

• Advantages: Very stable magnetic field at high temperatures (up to 350°C) and extremely good corrosion resistance.
• Disadvantages: More expensive due to the high cost of Cobalt. Less powerful than the strongest Neodymium types.
• Application: Aerospace, military applications, industrial ovens, and sensors.

AlNiCo (Aluminum-Nickel-Cobalt)

AlNiCo magnets are manufactured by casting or sintering and are known for their outstanding temperature stability.

• Advantages: Can be used at temperatures up to 500°C.
• Disadvantages: Very easy to demagnetize by external fields. The pull force is relatively low.
• Application: Measuring instruments, switches, and specialized industrial tools.

Factors Affecting Pull Force

The pull force shown in our webshop is measured under ideal conditions: perpendicular pull force on a thick, flat plate of pure steel. In practice, three factors play a major role:

1. Air gap: Even a thin layer of paint, dust, or a sheet of paper between the magnet and the surface reduces the force. The larger the distance, the weaker the attraction.
2. Material thickness: If the steel plate is too thin, it becomes "saturated." The magnetic lines cannot flow fully through the metal, causing the magnet to stick less effectively.
3. Shear force: If you hang a magnet vertically on a steel wall, it will slide down much sooner due to gravity than if you try to pull it from a horizontal surface. The shear force is usually only 15% to 20% of the nominal pull force.