Frequently Asked Questions
What exactly are neodymium magnets? Are they the same as "rare earth" magnets? Why are neodymium magnets the strongest magnets on the planet? How are neodymium magnets made? What does the "N rating" of your neodymium magnets mean? How is the strength of a magnet measured? Why are most neodymium magnets plated or coated? What other neodymium coatings are available? What are the primary uses of neodymium magnets? What are the most common applications of neodymium magnets? Why should I be so careful with neodymium magnets? Will stacking magnets together make them stronger? What is the best way to separate neodymium magnets? How can I identify the poles of the magnets? Is one pole, North or South, stronger than the other? Can I drill or machine neodymium magnets? Can I solder or weld to neodymium magnets? Can moisture and temperature affect neodymium magnets?
WORKING WITH NEODYMIUM MAGNETSWhat does "magnetized thru thickness" mean? What materials do neodymium magnets attract? What materials can I use to block/shield magnetic fields? Will totalElement neodymium magnets lose their strength over time?
What exactly are neodymium magnets? Are they the same as "rare earth" magnets?Back to top
Yes. Our neodymium magnets, which are manufactured to our specifications by various established firms around the globe, are part of the rare earth magnet genre. They are called rare earth because neodymium is a rare earth element on the Periodic Table.
Why are neodymium magnets the strongest magnets on the planet?
Mechanical engineers, physicists and other scientists consider neodymium magnets to be the strongest permanent magnets in the world because they create the highest magnetic field per size and volume of any other known natural or man-made material.
Developed by scientists during the 1970s and 1980s, neodymium magnets produce significantly stronger magnetic fields than all other ferrite, ceramic or alnico magnets. The magnetic field typically produced by rare earth neodymium magnets can be in excess of one-point-four (1.4) Teslas, whereas all other magnets normally generate fields of zero-point-five (0.5) to one (1) Tesla.
And not only are neodymium magnets the most powerful magnets on the planet, they are also the most affordable type of rare earth magnet available today.
How are neodymium magnets made?Back to top
Our neodymium magnets, also known as NIB or NdFeB magnets, are comprised of a neodymium, iron and boron compound referred to as Nd2Fe14B. This compound is actually a powdered mixture, and it is poured then pressed (using extreme pressure) into specially-cast molds, then sintered (heated under a vacuum), cooled, then ground or sliced into the desired shape.
Coatings (such as plastic, gold or the triple layer nickel-copper-nickel alloy plating we use) are then applied, if required. Finally, the blank magnets are magnetized by exposing them to a very powerful magnetic field in excess of 30 KOe. This enables them to perpetually produce their powerful magnetic pull or repel power.
What does the "N rating" of your neodymium magnets mean?Back to top
The magnet grade or "N rating" refers to the Maximum Energy Product of the material that the magnet is made from; and it refers to the maximum strength that the material can be magnetized to.
The grades of neodymium magnets that we normally carry are N42 and N48, a rating that is generally measured in Tesla metrics or units of Gauss Oersted (MGOe). A magnet of grade N42 has a Maximum Energy Product of Gauss 42 MGOe, while an N48 would be stronger. Generally speaking, the higher the grade number, the stronger the magnet will be.
How is the strength of a magnet measured?Back to top
Gauss meters are used to calculate the magnetic field density at the surface of a magnet, while the density or pull of the surface field is measured in Gauss or Tesla units. Pull Force Testers, which measure pull forces in pounds or kilograms, can also be used to test the holding force of a magnet that is in contact with a flat steel plate.
Why are most neodymium magnets plated or coated?Back to top
Neodymium magnets are composed mainly of neodymium, iron and boron. If they are not plated, the iron in the material will oxidize very easily, particularly if exposed to moisture. Even normal humidity will rust any iron anywhere over time. That’s why, in order to preserve and protect the lasting performance of each neodymium magnet’s magnetic field, most neodymium magnets are plated or coated.
Nickel is the most common choice, as it is durable and cost-effective. Our magnets are coated with a triple plating of nickel-copper-nickel. This creates a shiny silver finish and provides dependable resistance to corrosion in most applications. It is important to remember that no neodymium magnet, even with a plastic or gold coating, is completely waterproof.
What other neodymium coatings are available?Back to top
Other coating options include black nickel with a charcoal or gunmetal color. A black dye is added to the final nickel-plating process of the triple plating of nickel-copper-black nickel, but it is also still shiny and similar to a nickel-plated magnet.
Zinc coated magnets have a dull gray/bluish finish and are more susceptible to corrosion than nickel. Zinc can leave a black residue on hands and other items.
Epoxy or plastic coatings are also available, which are more corrosion resistant than a nickel-plating, as long as the coating remains intact. Unfortunately, this coating is easily marred and scratched during use and is considered the least reliable of the available finishes.
Finally, there is gold, which can be applied over the top of standard nickel plating. Gold-plated magnets have the same characteristics as nickel-plated ones, but with a lustrous gold finish (and price) of course!
What are the primary uses of neodymium magnets?Back to top
Neodymium magnets are used in numerous applications requiring strong, compact permanent magnets, such as electric motors for cordless tools, hard drives, magnetic hold-down or attachment fasteners and jewelry clasps.
Originally, the high cost of these magnets limited their use to applications requiring compactness together with high field strength. Both the raw materials and the patent licenses were expensive. But over the last few decades, NIB magnets have become steadily less expensive, and the low cost has inspired new uses such as magnetic construction toys, as well as a myriad of other hobby, engineering, energy-source, construction and manufacturing applications.
What are the most common applications of neodymium magnets?Back to top
The most common places you’ll find neodymium magnets include:
- Bicycle dynamos.
- Crafts, hobbies and jewelry.
- Computer hard drives.
- Health bracelets, bandages and other medical devices.
- Magnetic resonance imaging devices.
- Wind turbine generators.
- Fishing reel brakes.
- Permanent magnet motors in cordless tools.
- High-performance AC servo motors.
- Traction motors.
- Integrated starter-generators in hybrid and electric vehicles.
- Mechanically powered flashlights which use magnets for generating electricity from a shaking motion.
- Industrial and testing/quality control applications such as for verifying and maintaining product purity and equipment protection and integrity.
- Linear motors used in mag-lev trains and other motorized model equipment.
- Scientific applications such as diamagnetic levitation experimentation, the study of magnetic field dynamics and superconductor levitation.
- Electro-dynamic bearings.
- Roller coaster and other thrill ride technology.
- Magnet toys.
- Audio speakers and headphones.
- Electric guitar pickups.
- Miniature figures and models.
WORKING WITH NEODYMIUM MAGNETS
Why should I be so careful with neodymium magnets?Back to top
They are surprisingly strong, much more powerful than most other magnets you may have handled. As a result, the greater force exerted by neodymium magnets creates hazards that are not seen with other types of magnets.
Neodymium magnets that are larger than a few centimeters are strong enough to cause injuries to body parts pinched between two magnets, or a magnet and a metal surface, even causing broken bones.
Magnets allowed to get too near to each other can suddenly jump together and strike each other with enough force to chip and shatter the brittle nickel coating, and the flying chips can also cause injuries. This is why eye protection is essential when working with these magnets.
There have even been cases where children who have swallowed several magnets have had a fold of the digestive tract pinched between the magnets, causing injury and, in one case, even death.
Will stacking magnets together make them stronger?Back to top
Absolutely. Two or more magnets stacked together will exhibit exactly the same strength of a single magnet of the combined size. For example, if you stacked two of our 1/2” in diameter by 1/8” in thickness disc magnets to make a 1/2" x 1/4" combined size, the two magnets would have the same strength and behave identically to a 1/2” by 1/4" magnet.
What is the best way to separate neodymium magnets?Back to top
Slide them apart. Most stacks of magnets that are up to 3/4” in diameter and 1/4” in thickness can be slid apart by hand. Simply grasp or slip your fingernail between the magnets at the point you want to separate them and slide them away from the stack.
Be careful to slide the magnet or magnets far enough away so that they do not jump back on to your stack and possibly chip or pinch your finger.
For magnets larger than 3/4” in diameter and 1/4” in thickness, you may not be able to slide them apart and may want to invest in an inexpensive splitter made of wood. These splitters are made for both left and right-sided operation. You may also be able to improvise by using the edge of a table, counter or workbench as a fulcrum to separate larger magnets, but again, be extremely careful that you quickly move them apart and away so that they do not jump back together – which they will – unexpectedly.
How can I identify the poles of the magnets? Back to top
There are a few different ways you can identify the (Scientific) North and South poles of our neodymium magnets.
The easiest way is to use another magnet that is already marked. The North pole of the marked magnet will be attracted to the South pole of the unmarked magnet.
If you take an even number of magnets and pinch a string in the middle of the stack and dangle the magnets so they can rotate freely on the string, the North pole of the magnets will eventually settle pointing North.
While this contradicts the "opposites attract" law of magnetism, poles were originally called "North-seeking" and "South-seeking". These names were shortened over time to the "North" and "South" poles they are known as today.
Another method? If you have a compass, the end of the needle that normally points North will be attracted to the South pole of the neodymium magnet.
Is one pole, North or South, stronger than the other? Back to top
No, both poles of a magnet exhibit the same strength.
Can I drill or machine neodymium magnets?Back to top
Generally speaking, no. All neodymium magnets are very hard yet brittle, making any form of machining unworkable. The hardness of the neodymium nickel coating is rated at RC46 on the Rockwell "C" scale, and this is harder than commercially available drill bits and tooling. As a result, these tools will heat up and become damaged if used on NdFeB material.
Machining of neodymium magnets can be done, but should only be performed by experienced machinists familiar with the risk and safety issues involved. Normally, diamond tooling, EDM (Electrostatic Discharge Machines), and abrasives are the preferred methods for shaping neodymium magnet material.
It is important to remember however that the heat generated during machining can demagnetize the magnet and could cause it to catch fire posing a safety risk. The dry powder produced while machining is also very combustible and flammable – creating another very serious safety and health risk.
Can I solder or weld to neodymium magnets?Back to top
No. You cannot solder or weld to neodymium magnets. The heat will demagnetize the magnet and could cause it to catch fire. See above.
Can moisture and temperature affect neodymium magnets?Back to top
Yes. Although they have the highest magnetic field strength and have a higher coercivity (which makes them magnetically stable), neodymium magnets have a lower Curie temperature and are more sensitive to heat and vulnerable to oxidation than samarium-cobalt magnets.
While neodymium magnets have been proven to retain their effectiveness up to 80°C or 175°F, this temperature may vary depending on the grade, shape and application of the particular magnet. If a magnet heated above its maximum operating temperature (176°F or 80°C for standard N grades) the magnet will permanently lose a fraction of its magnetic strength. If heated above their Curie temperature (590°F or 310°C for standard N grades), they will lose all of their magnetic properties.
Corrosion can cause unprotected magnets to spall off a surface layer, or to crumble into a powder. Use of protective surface treatments such as gold, nickel, zinc and tin plating and epoxy resin coating can provide corrosion protection – although nickel is the most durable, practical, cost-effective and dependable.
Our magnets, which are finished using a three-layer nickel-copper-nickel plating, provide enough protection for most applications. But remember, neodymium magnets are not waterproof. They will rust or corrode in the presence of moisture. If used underwater, outdoors or in a moist environment, they can corrode and lose magnetic strength.
What does "magnetized thru thickness" mean?Back to top
We use the description "magnetized thru thickness" to identify the locations of the poles on some of our block magnets. It means the magnets stick or repel in the middle, rather than at the end of the block.
What materials do neodymium magnets attract? Back to top
Ferromagnetic materials are strongly attracted by a magnetic force. The elements iron (Fe), nickel (Ni), and cobalt (Co) are the most commonly available and attracted elements. Steel is also very susceptible or attracted to a magnetic field because it is ferromagnetic as an alloy of iron and other metals.
What materials can I use to block/shield magnetic fields?Back to top
Magnetic fields cannot be blocked, only redirected. The only materials that will redirect magnetic fields are materials that are ferromagnetic (attracted to magnets), such as iron, steel (which contains iron), cobalt, and nickel. The degree of redirection is proportional to the permeability of the material.
Will totalElement neodymium magnets lose their strength over time?Back to top
Very little. If they are properly handled, which includes not overheated or physically damaged, our neodymium magnets will lose less than 1% of their strength over 10 years. This is not enough to notice without very sensitive measuring equipment. In addition, the neodymium magnets we offer will not lose their strength even if they are held in repelling or attracting positions with other magnets over long periods of time.
If you have any other questions regarding our neodymium magnets, please contact us or call us at 855-328-2822 between 9:00 AM and 5:00 PM MST Monday through Friday, excluding holidays. We look forward to hearing from you!