Alnico Disc Magnets

Alnico Disc Magnets are permanent magnets made from an alloy of aluminum (Al), nickel (Ni), and cobalt (Co), along with iron and other trace elements. Known for their high magnetic strength, excellent temperature stability, and corrosion resistance, they are widely used in sensors, motors, and industrial applications. These disc-shaped magnets offer a strong magnetic field with reliable performance in extreme conditions. Their durability and resistance to demagnetization make them ideal for precision instruments and automotive systems.

Key Features of Alnico Disc Magnets

1. High Temperature Resistance: Alnico magnets maintain stable performance up to 550°C (1022°F), with a maximum operating temperature of 450°C (842°F) for most grades. This exceeds neodymium magnets' typical 80-200°C limit.

2. Superior Coercivity: Grade 5 Alnico exhibits intrinsic coercivity (Hci) of 640 kA/m, while Grade 8 reaches 1400 kA/m, ensuring resistance to demagnetization in harsh environments.

3. Consistent Magnetic Output: These magnets deliver a residual induction (Br) ranging from 0.6 to 1.35 Tesla, with energy products (BHmax) between 10-45 kJ/m³, providing reliable field strength for decades.

4. Exceptional Corrosion Resistance: Unlike rare-earth magnets, Alnico requires no coating, maintaining >95% magnetic flux retention after 10,000 hours in 85% humidity (per ASTM D2247 testing).

5. Precision Manufacturing Tolerance: Standard discs achieve dimensional accuracy of ±0.05mm on diameter and ±0.1mm on thickness, with custom options reaching ±0.01mm for critical applications.

6. Long-Term Stability: Alnico magnets exhibit <0.1% annual flux loss under normal conditions, outperforming ferrite (0.5-2%) and sintered NdFeB (1-3%) magnets in aging tests (per IEC 60404-8-1).

Applications

• Electric Motors & Generators: Alnico Disc Magnets are widely used in brushed DC motors, sensors, and small generators due to their high-temperature stability and strong magnetic field retention.

• Acoustic Equipment: These magnets are essential in guitar pickups, microphones, and loudspeakers where consistent magnetic performance and corrosion resistance are required.

• Medical Devices: Alnico discs serve in MRI components, dental equipment, and therapeutic devices where precise magnetic fields and durability are critical.

• Automotive Systems: Used in speedometers, ABS sensors, and ignition systems where reliability under varying temperatures is necessary.

• Industrial Sensors: Employed in proximity switches, flow meters, and position sensors due to their stable magnetic properties over time.

• Educational & Scientific Tools: Ideal for physics experiments, magnetic levitation demos, and laboratory equipment requiring long-lasting magnetization.

FAQ

Q: What are Alnico Disc Magnets made of?
A: Alnico disc magnets are composed of aluminum (Al), nickel (Ni), and cobalt (Co), along with iron and other trace elements.

Q: What are the key properties of Alnico Disc Magnets?
A: They offer high magnetic strength, excellent temperature stability, and strong resistance to demagnetization.

Q: Where are Alnico Disc Magnets commonly used?
A: These magnets are widely used in sensors, electric motors, guitar pickups, and medical devices.

Q: How do Alnico Disc Magnets compare to neodymium magnets?
A: Alnico magnets have lower strength but better heat resistance, while neodymium magnets are stronger but more temperature-sensitive.

Q: Can Alnico Disc Magnets lose their magnetism?
A: They are highly resistant to demagnetization but can lose strength if exposed to extreme heat or strong opposing magnetic fields.