How Long Do Neodymium Magnets Last?
Neodymium magnets don’t last forever. The life cycle of a magnet begins with manufacturing to packaging, shipping, unpacking, application, storage, reuse, more storage, and more reuse until finally, it loses some magnetism and becomes replaced by a newer version or a stronger grade.
Of course, this is a theoretical life cycle, as some neodymium magnets are only used once. Industrial neodymium magnets, for instance, are often positioned in a specific process and kept there for years before being replaced. And there are tiny magnet sizes that don’t make it to the application stage but are kept in the store, joining other magnets with similar fates. Any magnet enthusiast or user will be curious to find out the duration of an average neodymium magnet, as this informs usage and storage decisions.
Neodymium magnets do not have a specific, measurable shelf life. When we talk about a magnet’s lifespan, we are concerned with how long it takes a magnet to become non-magnetic. The easiest way to preserve a magnet’s longevity is to store them in a cool place, away from extreme temperatures. This article discusses the observable longevity of neodymium magnets and effective steps for maintaining and preserving neodymium magnets.
The Lifespan of Neodymium Magnets
Modern neodymium magnets can withstand decades of external adverse conditions and remain magnetic. Yet, if these neodymium magnets lose their ability to induce a net magnetic field, they can become partially demagnetized, affecting their performance and shortening their lifespan.
Different grades of neodymium magnets have different hypothetical lifespans. A ferrite magnet, found in households globally, will not last as much as a neodymium magnet. Neodymium magnets are the strongest rare earth magnets known today. Formed from an alloy of neodymium, iron, and boron, these neodymium magnets can sometimes go centuries without demagnetization or weakening. Their magnetism remains a permanent feature.
Neodymium magnets come in grades; the higher the grade, the stronger the magnetic field it induces. Over one decade, neodymium magnets can lose up to 5% of their magnetism. This will depend on the environment within which the magnet is being used, the storage and preservation techniques, and the quality of the magnet purchased from the manufacturer.
One bar of neodymium magnet can be recycled for up to one hundred years; however, neodymium magnets should be replaced before one hundred years is completed, as this will ensure that only premium neodymium magnets are being used for your operations. The electronic arrangement in the core of a magnet can be altered to affect the quality of the magnet; a disrupted arrangement will disrupt the magnetic force field induced, which will lessen a magnet’s performance.
Factors That Affect the Shelf Life of a Neodymium Magnet
Though permanent neodymium magnets are designed to induce the strongest magnetic fields, their operating environment affects their performance. An N42H magnet used within an industrial furnace zone will weaken, as “H’ grade neodymium magnets are effective at temperatures below 120C.
The weakening of neodymium magnets directly affects their longevity; thus, factors that cause weakening also affect the shelf life of neodymium magnets. The important ones are:
- Exposure to extreme temperatures: An average magnet has a maximum operating temperature corresponding to its grade. Suppose a magnet is brought into an environment outside this maximum temperature, as in the case of an N42H magnet near an industrial furnace of at least 400C. In that case, it loses its magnetic effect and begins to weaken, shortening its lifespan.
To this end, manufacturers rate neodymium magnets based on their temperature limits. Thus, an “SH” magnet designed to operate at 150C will be adversely affected if used in processes operating at 200C. To prevent this, manufacturers assign ratings to neodymium magnets to serve as guides for users. Loss of magnetism also occurs with very low temperatures.
When a magnet is subjected to temperatures drastically below its operating range, it reduces magnetic strength; most of this magnetism is restored once the magnet is withdrawn from the low-temperature environment. However, very high temperatures may result in a permanent magnetism loss, meaning that the magnet’s lifespan has been cut to zero.
- Age: A newly manufactured neodymium magnet has an undefined lifespan. The packaging and shipping primarily determine the longevity of its lifespan. Standard magnet manufacturers ensure premium packaging and shipping to preserve the manufacturing quality of neodymium magnets, extending their lifespan.
A well-made magnet should last as much as two decades without being degraded to a non-magnetic state. The degree of this degradation, if any, depends on the storage conditions of the magnet, the processes where the magnet has been used, and the quality of neodymium magnets at production. Reduction in magnetic strength sometimes occurs as a subtle process rather than a sudden, abrupt one.
- External Magnetic Fields: An external magnetic field can cancel out a magnet’s force field. Neodymium magnets that are unshielded from these charges experience a reduction in magnetic strength, particularly if the external field has a stronger force than the magnet’s inherent field. Most neodymium magnets, being of high strength, are not vulnerable to these external attacks.
- Environment and Humidity: Neodymium magnets contain iron, which on exposure to water and atmospheric air, becomes oxidized and corroded. If unattended, the corrosion will create spots on the neodymium magnets, which creates a platform for further oxidation and corrosion. A corroded neodymium magnet only retains a portion of magnetism and can become non-magnetic.
Maintaining neodymium Magnets to Preserve Their Lifespan
Maintenance enhances elongation. Here are the effective ways to preserve a magnet’s lifespan:
- Prevent corrosion: We addressed the effects of corrosion on neodymium magnets, regardless of their strength at manufacturing. A corroded magnet is weaker and more vulnerable to lose in magnetism. Build your magnet’s longevity by keeping them away from wet surfaces. Wipe them with dry napkins if they come in contact with moisture or watery spaces. For specific applications in wet environments, purchase and use neodymium magnets manufactured as moisture-conducive, and clean such neodymium magnets regularly.
- Store neodymium magnets in pairs: Remember the golden rule of pole-pole interaction? Opposing poles attract, while like poles repel. Ensure that the same poles of different neodymium magnets aren’t placed parallel to each other; not doing this will make the fields repel and weaken the fields’ intensity. Likewise, the north poles should not touch the south poles. They may lie close to one another but should not be in contact.
- Use a keeper. A keeper “keeps” your magnet’s north pole from interacting with the south pole. This prevents demagnetization by channeling the magnetic field lines along the right paths, eventually ensuring that the neodymium magnets last longer than they usually would.
- Package and ship neodymium magnets in non-ferromagnetic spaces. Keep your neodymium magnets in containers that won’t exert magnetic or electric forces. Wooden or hard cardboard boxes are great for storing neodymium magnets. They will prevent spontaneous reactions and prevent neodymium magnets from drawing debris.
- Keep from out-of-range temperatures. As discussed, temperature affects a magnet’s behavior. In chemical reactions, the temperature is a key factor in speeding up or slowing down the rate of completion of reactions. Temperature, pressure, and the presence or absence of a catalyst determine how a chemical reaction forms. Thus, many reactions are designed to be performed within specific ranges; taking these reactions outside of the assigned ranges will affect the results obtained. Likewise, extremely high or low temperatures will alter the electronic arrangement within the core of a magnet, thus altering its strength.
- Purchase quality neodymium magnets: If well-used, a magnet of poor quality will possibly weaken within a few years. The manufacturing process is a primary determinant of a magnet’s longevity. Before purchasing your neodymium magnets, research the magnet sellers. Do they run a manufacturing outlet or only trade neodymium magnets for users and other enthusiasts? Experienced neodymium magnet manufacturers, such as ROBO Magnetic, will not only pack and ship premium neodymium magnets to you, but they’ll also offer you expert counsel, on magnet maintenance and preservation.
- Proper casing: Keep neodymium magnets cased when not in use. Most neodymium magnets are shipped with accompanying rubber coatings. This serves multiple purposes: one, the coatings insulate the neodymium magnets from stray electric or magnetic fields; two, they prevent neodymium magnets from bumps due to transportation and movements; three, they keep the neodymium magnets from exposure to humidity. If a rubber coating wears out, do not hesitate to contact your magnet supplier for a replacement. This will keep your neodymium magnets from weakening or wearing out.
Keep a routine inventory of your store. If you have old, unused neodymium magnets, you want to get rid of them before purchasing new batches. Research the necessary neodymium magnets for the projects you intend to undertake and invest in premium purchases. Neodymium magnets will weaken someday; proper maintenance will elongate the timeline, boosting your neodymium magnets’ lifespan.
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