7 Applications of Neodymium Magnets

Neodymium magnet is one type of rare earth magnets which can be seen in many daily goods including headset, voice coil motor, guitars, speakers, Halbach array, cordless tools and even hybrid vehicles.
1. Magnetic pull bait plate
Fishing is so popular. There are special fishing TV stations introducing different fishing contest, fishing tips and fishing tackle. I am sure it’s one of the best-loved hobbies all over the world. Have you ever heard magnetic pull bait plate? It’s a fishing tool to adsorb fishhook for easy bait.

Magnetic hanger
2. Magnetic scrubber
Permanent magnets are widely used in aquarium cleaner because you don’t have to empty the tank or touch water any more. This also applies to narrow shape vast or glass door/window.
3. Magnetic gun mount
As all guns have something in common – metal, permanent magnets are ideal for building the gun mount. Use cheap big block ceramic magnets to build a gun mount, instead of small super-strong neodymium magnets or you can find free neodymium magnet in an abandoned computer hard drive.

Magnetic Tools
4. Magnetic beer buff opener
Small beer bottle caps are everywhere when you have fun with friends? Easy in assembly, magnetic bottle opener, can hold dozens of or even hundreds of caps a time.
5. Magnetic screen door
When summer comes, how to keep annoying mosquito or bug out is a big problem for many families, especially for those family that has baby. The magnetic mesh hands-free screen door curtains are the perfect solution to this problem; they are environmental protection without the use of pesticides and allow fresh air in.
6. Magnetic jar holders
If you have many small things taking up room in your cabinets and drawers, and don’t have extra space to hold more things, let’s use magnetic jar.

Magnetic pull bait plate
7. Magnetic hanger
If you are a neat freaks and want everything in order, you’ll love this modern magnetic clothes hangers. These hook-free hangers make it easier to organize your closet.

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How to Delivery Super Strong Magnets By Air

How can we shield a magnet package? At present, a common iron sheet is the main material to shield the magnetic field.

Magnetic shielding requires high permeability material. Ferronickel is such type material which can meet the requirement.

If magnet goods past inspection and have Identification and Classification Report for Air Transport of Goods, then strong rare earth magnet can be sent by air. Into order to past the inspection requirement by IATA (International Air Transport Association) DGR, we need to do some special treatment for the package.

magnet package

Due to the interference of weak stray magnetic fields on the navigation system and the control signal of the aircraft, IATA listed magnetic goods as Class 9 dangerous goods and meanwhile limited its delivery. For this reason, have you ever wondered about how to delivery super strong rare earth magnets by air?

Under the terms of the IATA DGR: if the maximum magnetic field strength of any air cargo is less than 0.159A / m (200nT) with distance 2.1m (7ft) away from the outer surface of the package, then this item can be treated as normal cargo to be airlifted, and is not subject to any restriction of magnetic substance.

Please pay attention that there must be a gap between the iron sheet and the magnet. And you can fill the air gap with any nonmagnetic material as support.

super strong rare earth magnet

For larger size magnet, it is difficult to reach total shielding requirements only by a single layer of shielding material. We have two other ways to solve this problem. One is increasing the thickness of the iron plate.

The other is a combination of shielding, putting one shielding into another shielding, leaving a certain gap between them. Combination of shielding is much better than single layer shielding which can reduce magnetic field to a low level.

The magnet for air transportation from Stanford Magnet is well packed by iron boxes. And we have excellent special express forwarders who help us to send magnets safely for many years. Low express cost and fast delivery time are available. If you have any requirement for magnet or magnet assemblies such as Halbach array, voice coil motor, please contact us freely.

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What Are Beer Loft Magnets

Neodymium magnet raw magnets are widely used in the industrial field, such as the speaker, louder speaker, sensor, motor, alternator; and also it is popular in ladies bags, purses, shoes, crafts and jewelry.

Small beer bottle caps go everywhere while having a party with our friends. Now an amazing item called magnetic bottle opener solves this problem with the combination of the permanent magnet and traditional bottle opener.

beer loft magnet

With wall-mounted design, strong neodymium magnets can grip beer bottle caps up to twenty or more depending on how strong the magnet is. Most of the time, sintered neodymium magnet with grade N52 neodymium magnet is the most common option.

beer bottle loft magnet

Grade N52 is stronger enough and affordable magnet type. Neodymium N52 maximum working temperature is 60 Celsius degree, so keep magnetic bottle opener away from fire or other high-temperature places.

Stanford Magnets is an experienced manufacturer of permanent magnets for woodworking including big disc neodymium magnet and strong block rare earth magnets. We are happy to work with your talent design no matter how big your order is.

Magnetic beer bottle loft magnet

To choose the right shape and size of beer loft magnets, Stanford Magnets did some experiments to get the right data. We have advanced R&D center, quality control, and professional machining technicians. So if you want to design your own magnetic bottle opener, you can get a reference from us.

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What are Neodymium Magnets Coated With

Epoxy (KTL)
Our Epoxy coating is a cathodic dip-paint coat (KTL). Unlike our Epoxy varnishing technique and the NiCu Epoxy coating, the Epoxy KTL coating features special stability in moist environments and in contact with weak acids as well as alkaline and saline solutions. Due to these properties, the Epoxy KTL coating is highly recommended for applications in tidal power plants and Offshore-wind turbines. Furthermore, the KTL coating offers a significantly better strip-off performance for glue-sheer off tests.

Epoxy
Galvanic Nickel plating (NiCuNi)
The galvanic nickel plating is a widespread method to coat sintered NdFeB-magnets. The coating is applied to the magnet in three layers: A basic Ni-layer, middle Cu- and at last a covering Ni-layer. The galvanic nickel plating has advantages considering the rigidity of the surface, the cost-effective production and the outstanding stability in moist environments and under high temperature. On the other hand, it is difficult to meter the thickness of the layers. Additionally, the method results in a problematic adhesion and in a loss of magnetic flow caused by short circuits.

Nickel plating magnet
Nickel electroplating (NiCuNi)
This process is similar to the galvanic nickel electroplating. Unlike the galvanic nickel surface coating, the final Nickel layer is plotted chemically. This technique results in improved corrosion protection under the terms of sterilization, a reduced loss of the magnetic flux and enhanced adhesive properties.

Galvanized Nickel-Tin (NiCuSn)
The cost-effective galvanized Nickel-Tin process is suited for applications in a wet environment that require an increased adhesive property. The reduced hardness of the final Tin layer has a disadvantageous effect. It especially exacerbates the handling of magnetized items.

Galvanized Zinc (Zn)
The zinc coating of NdFeB magnets is a widespread technique. It is the custom that a chromate coating is applied to the galvanized parts in a special bath. The customer can decide between a blue and a yellow chromate coating. The Cr+6 –rich, “yellow” coating is not applied in the automotive- and ROHS-conform production anymore, due to its manufacturing processes that are hazardous to health. The customer can fall back on the “blue”, sometimes called “white”, chromate coating. This coating offers lower corrosion protection compared to the properties of the “yellow” coating. On the other hand, it excludes impairments of human health and damages to the environment. The zinc coating can only be recommended for temperatures up to 80° C, due to its mechanical stability. The simple identification of coating thickness and the good handling make this technique very attractive. The process is most appropriate in cases of zinc-coated carrier material.

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8 Factors to Affect the Magnetic Force of Magnets

The magnetic force for permanent magnet can stay for a long time but it is not really permanent. There are 8 factors which will affect magnetic force.

1. Working temperature
The strong magnet is very sensitive to working temperature, especially for sintered NdFeB magnet. The momentary and continuous highest temperature of the environment may cause certain demagnetization including recoverable and unrecoverable, reversible and irreversible. According to working temperature range 80-200 celsius, sintered NdFeB magnet is divided into several grade series (N, M, H, SH, UH, AH etc.).
The cost will be expensive for high working temperature grade. So you need to consider your working temperature and choose the right grade. The loss of magnetic force can be ignored under working temperature permitted range. But magnetic force will decrease rapidly while working under a limit working temperature for a long time.

Magnetic Force

2. The material formulation
Material formulation limits magnetic properties fundamentally. Sintered NdFeB magnet is the strongest and alnico is the weakest. There is also the difference for the same material based on formulation. The magnetic force for grade N45 is higher than grade N35 for the same size magnet.

3. Magnet size and shape
Magnets come in all shapes and sizes, and are used for a great variety of purposes. The shape of a magnet determines how the magnetic field lines are arranged outside of the magnet, which affects what the magnet can be used for.

All of the methods you mention have been and continue to be used to manufacture magnets. Some small ones may be stamped out of sheet metal. Others may be cut from blocks of metal. Others still may be poured into molds.

Refrigerator magnets are probably made of molten plastic with iron powder mixed in, poured on a flat surface, and then cut into rectangular (or other) shapes. The magnetization procedure usually involves heating up the magnet and then cooling it off with an external magnetic field applied.

4. External magnetic field
Magnetic force will reduce while placing opposite poles around the magnet, only when the magnetic field of opposite poles is several times larger than magnet itself, the reduction will be evident.

5. The magnetization saturability
Only when fully charged, the magnetic force can be achieved completely.

6. Design of magnetic circuit
Different magnetized direction, the magnetic force is different. For a cylinder magnet, magnetic force by axial-magnetized is stronger than diameter-magnetized.

7. Working humidity
Sintered NdFeB magnet is easy to be oxidized and then loses its magnetic force. We use a coating to avoid this problem. But this is not a permanent solution. So the dryer it is, the better it is.

8. Strong shock
It will reduce magnetic force, but needs a long time.

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The Most Popular Motor Magnets-Neo Arc Magnet

Arc segment motor magnet has advantages of easy manufacture and low cost compared with radial ring magnets. It’s still the most common motor magnet shape, especially for PM DC motor and magnet rotor.

As we all know, permanent Magnet is the core of PM motor.
In order to ensure the steadily electrical performance and long-term safe and reliable operation of electric vehicles, it requires the magnetic property of permanent magnet material remains stable. Considering magnetic performance influenced by the work environment, temperature and time, the reliability of permanent motor magnets can be divided into thermal stability, time stability, chemical stability, and magnetic stability.

rare earth magnet

1. Temperature stability can be shown by Curie temperature and the maximum operating temperature. As the temperature rises, the magnetic properties gradually reduce. When raises to a certain temperature, the magnetization disappears. This certain temperature is the Curie temperature of the permanent magnet materials, also known as the Curie point. The deficiency of NdFeB permanent magnet is relatively low Curie temperature, but higher temperature coefficient. Therefore neodymium magnets will be lost much magnetic force if work under high temperature. Due to the high-temperature coefficient of NdFeB permanent magnet, the magnetic properties are poor. To this end, it must pay more attention to Max. working temp.of sintered NeFeB magnet when you select a magnet grade. The test method of magnet temperature stability is the aging test

2. Chemical stability refers to the anti-oxidation and corrosion-resistant of permanent magnet material. Compared with the traditional ferrite or samarium cobalt (Smco) or alnico magnets, the chemical stability of sintered NdFeB magnet is the worst. Currently, the primarily solution is adding some alloy elements such as Co, Ni, Al and Cr, etc., while in the sintering process, increasing the density and reducing the porosity of magnetic material. Another approach is made certain magnet surface treatment such as electroplating. This can obtain a practical corrosion resistance for the magnet.

3. Time stability is putting the permanent magnet at a certain temperature for a long time, observing the change of its magnetic properties over time. These NdFeB permanent magnets added Co + Dy + Nb will obtain better time stability.

4. Magnetic stability is based on the magnetic material, and also affected by temperature, time, external magnetic field, chemical corrosion, radiation, mechanical vibration or shock and other factors.

Compared with electro-magnetic, we can list more advantages of segment arc motor magnet:
1. Simplify the structure of the motor
2. Easy maintenance
3. Light weight
4. Small volume
5. Operational reliability
6. low energy consumption

How to choose motor segment material?
For traditional AC motor, ferrite and AlNiCo segment magnets are most applied. With the higher request on motor power, more and more motor manufacturers use ndfeb and smco magnet which have super high magnetic energy product. However, they are more expensive because neodymium magnet and samarium cobalt magnet segments belong to rare earth magnet.

How to join neodymium arc magnets, which are diameter magnetized, to create a cylindrical ring that is radially magnetized?
The general approach is to make a sleeve or frame to put neo arc magnets in that will keep them in order and don’t jump around. The sleeve here has to be made of something sturdy and nonmagnetic, such as aluminum, copper or Q235 low carbon steel. Due to a strong repelling force, it’s better to operate by those experienced workers. If you are the first time to assemble segment magnets, just be careful. Halbach array magnets also utilize a frame or other tools to overcome the strong magnetic repulsive force between the same pole sides of two magnets and keep them fixing together.

Why Does A Magnet Have Magnetism

There is a magnetic field around the magnet.

There is a magnetic field around the magnet, and the interaction between the magnets is mediated by the magnetic field. The magnetic field is a kind of special material that can not be seen or touched. The magnetic field is not composed of atoms or molecules, but it exists objectively. The magnetic field has the radiation characteristics of wave particles.

Since the magnetism of a magnet originates from current, which is the motion of charge, it is generally said that the magnetic field is generated by moving charge or changing electric field.

There is a magnetic field around the rare earth magnet. The interaction between the magnets is mediated by the magnetic field, so the two magnets can work without contacting.

Magnetic field characteristics

A magnetic field is a substance that exerts a magnetic force on the magnet placed in it. The basic characteristic of the magnetic field is that it can exert a force on the moving charges, that is, the electrified conductor is subjected to the force of the magnetic field in the magnetic field. This is why the magnetic field acts on the current, the force on the magnet or the force distance.

The magnetic field is a kind of special material that can not be seen or touched. The magnetic field is not composed of atoms or molecules, but it exists objectively. The magnetic field has the radiation characteristics of wave particles.

Charge and current movement produces the magnetic field

Principle of magnetic field generation

Modern physics has proved that the ultimate structure of any substance is composed of electrons (with unit negative charge), protons (with a unit positive charge) and neutrons (with an external display of electric neutrality). A point charge is a material point containing excess electrons (with unit negative charge) or protons (with a unit positive charge). Therefore, the reason why current produces magnetic field can only be attributed to the magnetic field generated by moving electrons.

Charge movement produces a magnetic field, electric current also produces the magnetic field. There are magnetic fields around the wires. Unlike atoms, the magnetic field is invisible and intangible. It generates magnetic field conditions. Charge movement is just like the principle that weight is absorbed on the earth.

magnetic field

The magnetic field is energetic.

The magnetic field generated by moving charge or changing electric field, or the total magnetic field is a passive and rotating vector field, and the magnetic lines are closed curve clusters, uninterrupted and uncrossed. The magnetic field is a rotational field rather than a potential field (conservative field), and there is no scalar function similar to the potential.

The electric field is an active irrotational vector field.

Geomagnetic field

The earth’s magnetic field comes from the inner part of the earth. The solid is surrounded by molten liquid iron and nickel. The movement of the earth’s center in the liquid metal produces electric current and forms the earth’s magnetic field. The magnetic field shielded the cosmic rays, mainly attacked by solar storms, and protected the continuity of life on Earth. Scientists have found that when volcanic magma solidifies, iron is always arranged in the direction of the magnetic field. Experts call this phenomenon geodynamics, and the earth’s magnetic field is dominated by the earth’s power.

What is Ferrite Used for

Ferrite is a ferromagnetic metal oxide. As far as electrical properties are concerned, the resistivity of ferrite is much larger than that of metal and alloy magnetic materials, and it also has a higher dielectric function. The magnetic function of ferrite also shows high permeability at high frequency. Therefore, ferrite has become an ordinary non-metallic magnetic material for high frequency and weak current limits. Because of the low magnetic energy reserved in the unit volume of ferrite and the low saturation magnetization, the application of ferrite in demanding high magnetic energy density at low frequency and high power band limits is limited.

Ferrite belongs to the category of semiconductor electronically, so it is also called magnetic semiconductor. Magnetite (the key component is Fe3O4) is a simple ferrite. Ferrite has been merged as early as the beginning of the 20th century. In the 30th century, France, Japan, Germany, and the Netherlands have carried out systematic discussions. The production of ferrite soft magnetic raw materials has been in the Netherlands since 1946. China started manufacturing ferrite industry around 1956. Ferrite has been widely used in communication, broadcasting, computing, automatic control, radar navigation, space navigation, satellite communications, instrument measurement, printing, pollution treatment, biomedicine, high-speed transportation, etc.

magnetic ferrites

1. Soft magnetic ferrites include manganese ferrite (MnO.Fe2O3), zinc ferrite (ZnO.Fe2O3), nickel-zinc ferrite (Ni-Zn.Fe2O4), manganese-magnesium-zinc ferrite (Mn-Mg-Zn.Fe2O4) and other single or multi-component ferrites. The resistivity is much larger than that of metal magnetic materials, and it has a higher dielectric function. Therefore, ferrites with both ferromagnetism and ferroelectricity and ferromagnetism and piezoelectricity appear. At high frequencies, it has much higher permeability than metal magnetic materials (including ferronickel alloy and aluminum-silicon-iron alloy). It can be applied to work at frequencies ranging from several kilohertz to several hundred megahertz. Processing ferrite belongs to the usual ceramic process, so the process is simple, and save a lot of precious metals, low cost.

The saturated flux density of ferrite is low, usually only 1/3-1/5 of iron. Ferrite has low magnetic energy reserve per unit volume, which limits its use in demanding high magnetic energy density at low frequency, high current, and high power band boundaries. It is more suitable for high frequency, low power, and the weak electric field surface. Nickel-zinc ferrite can be used as antenna rod and medium frequency transformer core in radio, and manganese-zinc ferrite can be used as line-conveying transformer core in the TV receiver. In addition, soft magnetic ferrites are also used to add sensors and filter cores in communication lines. High-frequency magnetic recording transducer has been used for many years.

2. Permanent magnetic ferrites include barium ferrite (BaO.6Fe2O3) and strontium ferrite (SrO.6Fe2O3). High resistivity, belongs to the semiconductor category, so eddy current consumption is small, the coercive force is large, can be used effectively in the air gap magnetic circuit, unique for small generators and ideas of permanent magnets. It does not contain precious metals such as nickel and cobalt. The raw materials are excellent, the process is not complicated and the cost is low. It can be used as a substitute for AlNiCo permanent magnet. Its contrast large magnetic energy product is lower, so it is larger than metal magnet in the condition of considerable magnetic energy. Its temperature stability is poor, its texture is brittle and fragile, and it can not withstand the impact and sensation. It is not suitable for measuring instruments and magnetic devices with careful requirements. The products of permanent magnet ferrite are mainly anisotropic series. They can be used to manufacture permanent magnet starter motor, permanent magnet motor, permanent magnet concentrator, permanent magnet suspender, magnetic thrust bearing, magnetic broadband separator, loudspeaker, microwave device, magnetic therapy sheet, hearing aid, etc.

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Can Permanent Magnet Motors be Used As Generators

The biggest difference between permanent magnet generator and excitation generator is that its excitation magnetic field is generated by the permanent magnet. A permanent magnet is not only a magnetic source, but also a component of the magnetic circuit in the motor.

The magnetic properties of permanent magnets are related to the manufacturing process, the shape and size of permanent magnets, the capacity of magnetizers and the method of magnetization. The specific performance data are very discrete. Moreover, the magnetic flux and magnetic potential provided by permanent magnets in motors also vary with the material properties, dimensions of the remaining parts of the magnetic circuit and the running state of the motor.

Permanent magnet generator has a variety of magnetic circuit structures. The leakage circuit is very complex and the proportion of leakage flux is large. The ferromagnetic material part is easy to be saturated, and the permeance is non-linear. All these increase the complexity of electromagnetic calculation of permanent magnet generator and make the accuracy of calculation lower than that of electric excitation generator.

permanent magnet generator

Like the alternator, the mechanical energy of the prime mover is converted into electric energy output by using the electromagnetic induction principle of the electric potential induced by the magnetic force line cut by the wire. It consists of stator and rotor. The stator is the armature that generates electricity, and the rotor is the magnetic pole. The stator is composed of armature core, uniformly discharged three-phase windings, frame, and end cover.

The magnet rotor is usually hidden pole type, consisting of excitation winding, iron core, and shaft, retaining ring, central ring, etc. The excitation winding of the rotor passes through the DC current and produces a nearly sinusoidal magnetic field (called the rotor magnetic field). Its effective excitation flux interacts with the stationary armature winding. When the rotor rotates, the magnetic field of the rotor rotates along with the same start and every turn. The magnetic wire cuts each phase winding of the stator sequentially, and induces a three-phase alternating current potential in the three-phase stator winding.

When the generator operates with symmetrical load, the three-phase armature current synthesizes to produce a rotating magnetic field with synchronous speed. The interaction between the stator magnetic field and rotor magnetic field will produce braking torque. From the steam turbine/gas turbine, the mechanical torque input overcomes the braking torque coupling and works.

magnet rotor

Advantages of Permanent Magnet Generator

I: It has a simple structure and high reliability. Permanent magnet generator eliminates excitation winding, carbon brush and sliding ring structure of excitation generator. The structure of the whole machine is simple. It avoids burning and breaking of excitation winding, carbon brush and sliding ring structure. The structure of the whole machine is simple. It avoids burning and breaking of excitation winding, wearing and tearing of carbon brush and sliding ring of excitation generator. The reliability is greatly improved.

II: Small size, lightweight, and high specific power. The use of permanent magnet rotor structure makes the internal structure design of the generator arranged very compactly, and the volume and weight of the generator are greatly reduced. The simplification of the permanent magnet rotor structure also reduces the inertia of the rotor, increases the practical speed, and achieves a very high specific power.

III: Medium and low-speed power generation performance is good. Under the same power level, the output power of the permanent magnet generator is twice as high as that of the excitation generator at idle speed. That is to say, the actual equivalent power level of the permanent magnet generator is the excitation generator.

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