Demagnetization of Magnets

When acquiring magnets, it is crucial to understand how to maintain their strength over time. How do usage and storage affect magnetism? What factors cause demagnetization, and how can it be prevented? This article answers these questions and more to ensure the prolonged effectiveness of your magnets.

Loss of Magnetization in Permanent Magnets

Over time, magnets experience a gradual loss of magnetization, though this process is very slow. Standard neodymium magnets, under optimal storage conditions, can lose less than 5% of their magnetization in a century. This resistance to change is called coercivity, and neodymium magnets have higher coercivity than ferrite magnets.

Causes of Demagnetization

Several factors can compromise a magnet’s magnetization. These include exposure to extreme heat or cold, intense magnetic fields, alternating electric current, vibrations, impacts, structural damage, oxidation, corrosion, and radiation.

Impact of Temperature

Excessive heat can damage the structure of magnets, reducing their strength. Neodymium magnets have a working temperature of up to 80°C, while ferrite magnets can withstand up to 250°C. Exceeding these temperatures can cause permanent loss of magnetization.

Proper Storage

Keep magnets in dry, protected environments, avoiding extreme temperatures. Store them separately to avoid mutual influence and protect them from strong electric currents, magnetic fields, and intense vibrations.

Demagnetization by Other Factors

Strong impacts or exposure to radiation can also weaken magnetization. Proximity to other magnets or sources of alternating electric current can cause progressive demagnetization.

Prevention and Care

Avoid drops, impacts, or welding near magnets. Protect them from moisture to prevent oxidation. If demagnetization is necessary, use specialized equipment to avoid irreversible damage.

Conclusions

Understanding how various factors affect the magnetization of magnets is crucial for their effective and long-lasting use. With proper storage and handling practices, you can maximize the lifespan and performance of your permanent magnets. Consult experts for specific guidance based on your needs and work environment.