Hard Magnets

Why Choose Us

Acro-Mag systems limited is a professional organization in manufacturing, sales and marketing Flexible Magnet and Magnet related products. Since established, we are improving our product range continuously, Our product line includes Flexible Magnetic Materials, Magnetic Printing and Display Materials, and Magnetic Finished products. We specialize in producing Ring Ferrite Magnet, Segment Ferrite Magnet, Retangular Neodymium Bottoms, Sintered Neodymium Magnets, and other Hard Magnets.

Wide Range of Applications

Our products are widely used in Promotion, Advertising, Gifts and Souvenirs, Commercial Visual Display, Interior Display and Decoration, Office and Stationary, Hobby and Crafts, Children's Education etc.

Quality Guaranteed

Our company has obtained a series of certifications such as BA Free testing for Rubber magnetic strips _EN, EC23002507101(GZP23-000976)-CAN Final-ACROMAG, Rubber magnet with EN-71 TESTING_EN, etc.

One-Stop Solution

We supply not only flexible magnet product, but also provide product solutions based on your application and requirement.

Quick Response

Our commitment is to respond to your inquiries within 24 hours, ensuring that you receive the information and support you require in a timely manner.

Sintered Neodymium Magnets
Sintered magnet: it is a kind of high-performance rare earth permanent magnet material with neodymium (nd), iron (FE) and boron (b) as the main components. It is easy to demagnetize at high...
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Retangular Neodymium Bottoms
NdFeB Magnet has the characteristics of high remanence, high coercive force, and high energy. Moreover, it is easily formed into variou sizes and shapes, which are ring, rectangular, segment, or...
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Segment Ferrite Magnet
Segment Ferrite Magnet is the core functional component of a permanent magnet DC motor. It is mainly used in automobiles (such as starter motor, glass lifter, wiper, automatic seat, automatic...
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Ring Ferrite Magnet
In 2004, three production lines for Ring Ferrite Magnet were been put into production. After more than ten years' development and technical transformation, Acro-Mag has three sintering furnace...
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What is Hard Magnets

Hard magnets, also referred to as permanent magnets, are magnetic materials that retain their magnetism after being magnetised. Practically, this means materials that have an intrinsic coercivity of greater than ~10kAm-1. If you want to know the specifications and prices of Hard Magnets, please contact us!

Advantage of Hard Magnets

Free Energy Source
Permanent magnet generators generate electricity with the inside magnets that can be used to power other electric devices, which means that you will no longer need to pay for the expensive electric bills. In addition, you can even sell your excessive electricity to local utilities and get payment from them.

Reliable Energy Output
Compared to generators powered by other renewable and green energy, solar energy and wind power, for example, permanent magnetic generators are working independently of factors inside or outside of your house. You will no longer need to worry about the weather.

Low Installation Fee
A permanent magnet generator will not cost you a lot of money to install. You only need to buy everything necessary in a hardware store with little money and assemble one by yourself. With only hundreds of dollars, in one day, or less time, you can have your own permanent magnet generators at home.

Maintenance Free
Another great thing about permanent magnet generators is that you do not need to spend a lot of time and money on the maintenance work. Just install it and wait there expecting it to make money for you!

Application of Hard Magnets

Automobile Manufacturing

Both hybrid and electric vehicles are manufactured using very powerful permanent magnets. The main principle used here is the ability of the magnets to convert mechanical force into electrical force. These magnets are an essential component of the vehicles and are made of materials with a high composition of rare earth magnets. These kinds of magnetic materials are pricey and limited in supply.

Loudspeakers

Loudspeakers contain a mobile electromagnetic coil, around which the permanent magnet is fixed. This setup uses the same principle in electric cars, where electrical energy is converted into mechanical energy. The electromagnetic material is attached to a diaphragm or cone, amplifying vibrations to emit sound waves. The frequency of the vibration controls the pitch or intensity of the sound produced by the loudspeaker.

Hard Disk Drive

Another place where permanent magnets find practical application is in disk drives. They play a central role in helping to store information in the drives. Hard disk drives (HDD) usually are made up of 3 permanent magnets. The mechanism involved in reading and writing information on hard disks is quite interesting.
A fixed magnet serves as the actuator, moving the read-write arm based on its interaction with an electromagnet. There's another small permanent magnet at the end of the read-write arm, which is in charge of the reading-writing actions using a platter. The third magnet is a spindle motor, which facilitates the movement (rotation) of the platter at high speed. This way, the HDD can read and store information.

Refrigerators

Did you know that a permanent magnet is used in making refrigerators? You may not have noticed it, but whenever you close the refrigerator, the small magnet embedded in the door is what allows the door to close. If you observe closely, the refrigerator's door usually acts as though the fridge itself is pulling it. That is the magnet at work! Unlike in electric generators and loudspeakers, the magnet, in this case, is not a strong magnet.

Jewelry

Permanent magnets are used in making your jewelry. Earrings, bracelets, necklaces, and beads contain permanent magnets that ensure they clasp together. Neodymium magnets, in particular, can be used to create bipolar magnetic neodymium jewelry.

Magnetic Drive Pumps

Pumps coupled with magnetic materials are helpful both in home gardens and industrial settings. The setup in magnetic drive centrifugal pump operation is similar to that of a standard centrifugal pump. However, the motor shaft seal is removed, eliminating leaks caused by shaft seal failure.
There are many more applications of permanent magnets in everyday life. Permanent magnets are used in headphones, induction cookers, MRI machines, particle accelerators, transformers, electric generators, and even door locks. For more information, please visit our homepage.

The Different Hard Magnets and Which One is Right for You

Ceramic
In most cases, you're probably going to use a ceramic magnet, as it's the most common material used to manufacture permanent magnets. Ceramic, or sometimes referred to as ferrite, magnets are made with several elements, such as sintered iron oxide and barium. These magnets are great for several reasons: first their magnetism is strong, so it's difficult to demagnetize over time. Another benefit of ceramic is that it won't rust, making maintenance rather simple. Alternatively, ceramic magnets can be extremely hard, making them fragile especially when dropped.

Alnico (AlNiCo)
For those who require a stronger magnetism, alnico magnets are excellent. Manufacturers primarily use aluminum, nickel, and cobalt to build alnico magnets. If your company handles materials at different temperatures, alnico magnets are probably the best option available for you. The reason is because they're stable at a wide variety of temperatures while maintaining strength. There are two common types of alnico magnets: cast and sintered. Cast alinco are the most common because there are several different grades, including options that are capable of maintaining most of their strength in temperatures over 1000 degrees Fahrenheit. Alternatively, sintered alnico magnets are typically weaker in terms of their magnetism, but they're better for mechanical uses.

Samarium Cobalt (SmCo)
Manufacturers build these magnets using samarium and cobalt and a sintering method. These are often found in what's called a rare earth grade, the strongest magnets available. Samarium cobalt magnets are extremely resistant to different temperatures and maintain their strengths. Many companies have samarium cobalt magnets for magnetic separation in several industries, such as pharmaceuticals, automotive, aerospace, manufacturing, and more. In other words, samarium cobalt magnets are one of the strongest and most versatile industrial magnets available on the market today.

Neodymium Iron Boron (NdFeB)
Like samarium cobalt, neodymium iron boron magnets are made with a rare earth material as well. The overwhelming advantage of neodymium iron boron magnets is that they're extremely strong. Additionally, they serve several applications which is why they're often found in places like magnetic separation setups, wind turbines, motors, and so on. However, there are two factors to keep in mind when considering neodymium iron boron magnets: temperature and corrosion resistance. These magnets don't have as high of a temperature threshold for them to operate in efficiently. In addition, neodymium iron boron magnets are more susceptible to corrosion than other magnet alternatives.

How to Choose Right Hard Magnets

Magnet Strength

The first thing to consider when choosing your magnet is its strength, the strength of a magnet can be measured in Gauss or Tesla, with higher numbers indicating stronger magnets.
However, the pull strength of a magnet is another measurement of strength, a magnet's pull strength is the force that's required to pull that magnet straight free vertically from a steel plate.
The strength of the magnet you require will be completely dependent on your application, for advice please be sure to contact our team for free no obligation advice.

Magnet Size

An important factor is the size of your magnet, this may already be determined by specifications from your application, but finding a magnet the correct size is an important step in choosing your magnet.
Typically, smaller magnets are weaker but are more versatile and easier to use in certain applications, whereas larger magnets are stronger and better suited for heavy-duty applications, but they can be more expensive.

Magnet Shape

Magnets come in many different shapes, including bars, rings, discs, horseshoes, cubes, and rectangles, the shape of the magnet you choose will have a direct impact on its usefulness.
The shape of the magnet you require will be dependent on your application, for example, a disc magnet may be used for more mechanical projects whereas horseshoe magnets are more commonly used for holding objects.

Magnet Material

Magnets come in a variety of different materials, each with its own unique properties. The most common magnet materials are neodymium, ceramic, alnico, and samarium cobalt.
Neodymium magnets are the strongest material available, whereas ferrite magnets are much more cost-effective, samarium cobalt magnets have a greater temperature resistance, and alnico magnets are also very strong.

Temperature Considerations

The temperature which a magnet will have to withstand in your application must be taken into consideration when choosing a magnet. Some magnets lose their strength at high temperatures and others may become permanently demagnetized.
Standard-grade neodymium magnets have a maximum operating temperature of 80 degrees Celsius. When heated above this, they will experience irrecoverable losses in performance. High-temperature grades of neodymium magnets with higher maximum operating temperatures are available.

How to Maintain Hard Magnets

Magnet Care and Maintenance
Extend the life of your magnets with these care and storage tips.

Use a Magnet Keeper
A magnet keeper is small iron or steel bar that's used to prevent a permanent magnet from becoming demagnetized. It's placed across the poles to complete the magnetic circuit and stop external metal from becoming attracted to the magnet.

Store Magnets in Pairs
To prevent the two south or two north magnet poles of different magnets from touching, store your magnets in pairs with the unlike poles on the same side. If both poles of the same alignment (north and north or south and south) are allowed to touch, the magnetic fields will repel and cause the magnet to weaken over time.

Store Magnets in a Dry Place
Magnets can be susceptible to corrosion and rust if stored in damp environments. This can lead an air gap that prevents the magnet from producing a secure bond on ferromagnetic materials. Laminated flexible magnets that become wet can bubble and distort. If you are using a magnet in a wet environment, make sure it's designed for water and is cleaned and dried regularly.

Avoid Ferromagnetic Storage Containers
Keep your magnets in a non-ferromagnetic or a non-magnetic, iron free container, like a wooden box or a plastic container. This well help prevent your magnets from attracting any metal debris.

Store Away from High Temps
Keep your magnets stored away from heat sources. Prolonged exposure to high temperatures will cause your magnets to weaken over time.

Store Away from Electric Currents
Strong electrical currents can disrupt a magnet's magnetic field and cause it to demagnetize. Store your magnets away from anything that gives off an electrical current, including microwave ovens, wireless routers and computers, as they can affect the strength of a magnet.

Protect with a Magnetic Assembly
Many magnets are sold as a magnetic assembly, with a protective casing or coating that surrounds the magnet. A magnetic assembly can help protect the surface of the magnet, prevent slippage and can even focus the magnetic force in one direction.

Start with High-Quality Magnets
Another way to make sure your magnets last as long as possible, is by using a reliable source for high-quality magnets. We have a huge selection of industrial magnets available in our online magnet store, or we can help you design any promotional magnet you can think of.

Common Hard Magnet Issues and How to Repair Them

Causes and Solutions
Magnetic Field Interference Causes Magnet Issues
Magnetic fields from external sources can interfere with the magnetization of a material, causing it to become demagnetized. This can occur when magnets are exposed to strong electromagnetic fields or placed in close proximity to other magnets. To repair demagnetized magnets affected by external magnetic field interference, you can:
●Shield the Magnet – Encase the magnet in a material with high magnetic permeability, such as mu-metal, to divert external magnetic fields away from the magnet.
●Repolarize the Magnet – Apply a strong magnetic field to the demagnetized magnet to realign its magnetic domains and restore magnetization. This can be achieved using a specialized magnetizer or by subjecting the magnet to a strong magnetic field.
High Temperatures
Exposure to high temperatures can lead to demagnetization of magnets. This is particularly true for magnets made from materials with low Curie temperatures. To repair demagnetized magnets due to high temperatures, follow these steps:
●Allow the Magnet to Cool – If the demagnetization occurred due to temporary exposure to high temperatures, allowing the magnet to cool down to room temperature may restore its magnetic properties.
●Replace the Magnet – In cases where the demagnetization is irreversible or the magnet has exceeded its maximum operating temperature, replacing the magnet with a new one is the most effective solution.

Cracks, Chips, and Breakage
Cracks in Magnets
Magnets are susceptible to cracking, especially if subjected to mechanical stress or sudden impacts. Cracks can compromise the structural integrity of the magnet and weaken its magnetic properties. When dealing with cracked magnets, consider the following repair options:
●Epoxy Resin – Fill the cracks with a suitable epoxy resin that is compatible with the magnet material. This will help restore the magnet's structural integrity and prevent further cracking.
●Reinforcement – For larger cracks or severely damaged magnets, reinforcing them with an additional structural component, such as a metal plate, can provide the necessary support and prevent further damage.
Chipped Magnets
Small chips or fragments can break off from magnets, particularly in brittle materials like ceramic or rare-earth magnets. To repair chipped magnets, you can:
●Reattach the Chip – If the chip is still intact, you can use a strong adhesive to reattach it to the magnet. Ensure that the adhesive is suitable for the magnet material and provides a secure bond.
●Smoothing the Surface – In cases where the chip is lost or damaged beyond repair, you can use fine sandpaper to smooth the surface of the magnet and remove any sharp edges.
Broken Magnets
When a magnet breaks into two or more pieces, it requires careful repair to restore its functionality. Here's what you can do to repair broken magnets:
●Alignment and Bonding – Align the broken pieces of the magnet and use a strong adhesive that is compatible with the magnet material to bond them together. Apply pressure and allow sufficient curing time for the adhesive to set.
●Reinforcement – In some cases, reinforcing the repaired magnet with additional support, such as a metal brace or band, can provide extra strength and prevent further breakage.

Corrosion and Rust Prevention
Surface Coating
Magnets made from certain materials, such as neodymium, are susceptible to corrosion and rust when exposed to moisture or harsh environments. To prevent and repair corrosion-related issues, consider the following measures:
●Surface Coating – Apply a protective coating, such as nickel, zinc, or epoxy, to the magnet's surface. This will create a barrier against moisture and corrosive substances, extending the magnet's lifespan.
●Regular Cleaning – Clean the magnet regularly using a mild detergent and water solution to remove any dirt or contaminants that may contribute to corrosion. Dry the magnet thoroughly after cleaning to prevent moisture accumulation.
Proper Storage
Storing magnets correctly is essential to prevent corrosion and rust. Follow these guidelines to ensure optimal storage conditions:
●Keep Magnets Dry – Store magnets in a dry environment with controlled humidity levels to minimize the risk of moisture-related damage.
●Avoid Direct Contact – When storing multiple magnets, prevent them from coming into direct contact with each other to avoid scratching or chipping.

Certifications

Frequently Asked Questions

Q: What is the difference between a hard and soft magnet?

A: A hard/permanent magnet can alone support a magnetic flux in a gap of a device; a soft magnet requires the assistance of an external electrical/magnetic input to do so.

Q: Is steel hard or soft magnet?

A: Steel is hard in terms of surface hardness (Rockwell or Vickers) but magnetically it's soft. Hardness in magnetism means how difficult it is to demagnetize a material after it's been magnetized, its coercivity, measured in oersteds (Oe) or amps/meter (A/m).

Q: What is an example of a hard magnetic material?

A: Alloys composed of iron, cobalt and aluminum are generally acted as hard magnetic materials.

Q: Is copper a hard or soft magnet?

A: But copper is so weakly magnetic that we can't observe it without very, very large magnetic fields. So the short answer is "No, copper isn't magnetic." This can quickly be tested by trying to pick up a penny with a magnet. But copper will interact with magnets in fascinating ways.

Q: Why is steel called hard magnet?

A: Magnetically hard steels have a high resistance to demagnetization and remain magnetized even after being exposed to strong external magnetic fields, while magnetically soft steels have a low resistance to demagnetization and become easily demagnetized when exposed to strong external magnetic fields.

Q: Is iron a hard magnet?

A: Some materials, such as iron metal, can exist as either hard or soft magnets. Whether bcc iron is a hard or soft magnet depends on the crystal grain size.

Q: What are the uses of hard magnets?

A: The most important uses of permanent magnets are in electric motors, generators and actuators. Their power ranges from microwatts for wristwatch motors to hundreds of kilowatts for industrial drives. Annual production for some consumer applications runs to tens or even hundreds of millions of motors.

Q: Is hard Aluminium magnetic?

A: How magnetic is aluminium? Under normal circumstances, aluminium is not magnetic, mainly because of its crystal structure. It's referred to as a paramagnetic material along with other metals like Magnesium and Lithium.

Q: What hard metal is not magnetic?

A: Many common metals such as aluminum, copper, brass, gold, silver, titanium, tungsten, and lead are not ferromagnetic. They cannot be made into magnets and will not be attracted to magnetic fields.

Q: What are hard magnets made of?

A: The examples of hard magnetic materials are alnico, ferrites, rare earth cobalt, cobalt platinum, etc. Some popular examples of soft magnetic materials are pure iron with small carbon content, siliconiron alloy, nickel-iron alloy, etc.

Q: Is copper a hard magnetic material?

A: Copper is non-magnetic. To be technically precise, pure copper is diamagnetic, meaning that it has no unpaired electrons and will interact with magnetic fields only very weakly. Most "non-magnetic" materials (such as water, plastic, wood, etc.)

Q: Can magnets attract carbon?

A: Not only is carbon the most covalent of the elements, it is not even magnetic in the atomic state since the spin and the angular momentum of its six electrons cancel to produce a net magnetic moment of zero. Given such anti-magnetic tendencies, carbon hardly seems likely to become the ferromagnet of the future.

Q: How do you make a hard magnet?

A: Take two magnets put one North pole and one South pole on the middle of the iron. Draw them towards its ends, repeating the process several times. Take a steel bar, hold it vertically, and strike the end several times with a hammer, and it will become a permanent magnet.

We're professional hard magnets manufacturers and suppliers in China, specialized in providing high quality products and service. We warmly welcome you to buy or wholesale hard magnets for sale here from our factory.

Ring Ferrite Magnet, Tin Photo Magnet, Magnetic Receptive Material