What are The Features of Adhesive Magnets

Adhesive magnets refer to 3M double-side adhesive NdFeB magnet. This magnet is usually used on box, purses, displays, electronic products and DIY household gadgets etc.

With the help of magnetic force and adhesive force, the 3M adhesive magnet is an idea link to the ferrous and nonferrous object.

It contains three parts: sintered NdFeB magnet (disc, block, oval or based on your design), adhesive (foam tape VHB4945, 467MP, 468MP etc.) and liner.

3M super strong ndefb adhesive magnet

The coating on the magnetic side can be glossy or matte, self-adhesive on nonmagnetic side

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

A magnet for badges fastener provides a professional way of displaying name badges and identification without damaging your clothing. Magnetic name badge holder is with a strong magnet and metal molded, which allows the tag to be easily clipped onto your shirt or suit without the damaging effects of pins or clips.

Magnetic name tags are perfect for suits or expensive clothing which you may like very much and you don’t want to be damaged. With strong permanent neodymium magnets attached, the magnetic id badge holder can be used over and over again, therefore it is also called a reusable magnetic name badge.

The Features of Adhesive magnets:
1. Ideal for professional or hospitality settings.
2. Additional fastener options including strap clips, lanyards, and magnetic are available.
3. Pocket badges do not need a fastener.
4. Available in multiple sizes and shapes.
5. Includes pin or swivel clip fastener.
6. Rectangle metal name badges come with square corners.

For more information, please visit https://www.stanfordmagnets.com/

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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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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Types of Permanent Magnet Materials

At present, the common permanent magnetic materials are ferrite, NdFeB, samarium cobalt, aluminium nickel cobalt, rubber magnetism and so on.
Each of the above magnets has its own characteristics and different application fields. The following are briefly introduced:
Ferrite magnet
Ferrite is a non-metallic magnetic material, also known as magnetic ceramics. We take apart the traditional radio. The horn magnet inside is ferrite. At present, the magnetic energy product of ferrite is only slightly higher than that of 4MGOe. One of the greatest advantages of this material is its low price. At present, it is still widely used in many fields. Ferrites are ceramics. Therefore, the machinability is similar to that of ceramics. Ferrite magnets are molded and sintered. If processing is needed, only simple grinding is needed. Because it is difficult to machine, most ferrite products are simple in shape and large in size tolerance. The square shape product is good and can be ground. Other dimensional tolerances are given as a percentage of nominal size. Because ferrite is widely used and inexpensive, many manufacturers will have ready-made circular rings of conventional shapes and sizes, such as diamonds and other products to choose from. Because ferrite is made of ceramics, there is basically no corrosion problem. The finished product does not need surface treatment or coating such as electroplating.

Permanent Magnet Materials
Rubber coated magnet
Rubber magnet is one of the series of ferrite magnets. It is made of bonded ferrite magnetic powder and synthetic rubber by extrusion, calendering and injection molding. It can be processed into the strip, roll, sheet, block, ring, and various complex shapes. Its magnetic energy product ranges from 0.60 to 1.50 MGOe in the application fields of rubber magnets: refrigerators, message boards, fasteners that fix objects to metal bodies for advertising, and magnetic discs for toys, teaching instruments, switches, and sensors. Mainly used in micro and special motors, refrigerators, disinfection cabinets, kitchen cabinets, toys, stationery, advertising, and other industries.

Samarium cobalt
Samarium-cobalt magnets consist mainly of samarium and cobalt. Samarium cobalt magnets are also the most expensive of several magnets because of the high price of the two materials themselves. The magnetic energy product of samarium-cobalt magnet can reach 30MGOe or even higher at present. In addition, samarium cobalt magnets have high coercivity and high-temperature resistance. They can be used at 350 degrees Celsius, so they can not be replaced in many applications. Samarium cobalt magnet belongs to powder metallurgy products. Generally, according to the size and shape of the finished product, the manufacturer sinters the block blank and then uses the diamond blade to cut into the finished product size. Because samarium cobalt is conductive, it can be processed by wire cutting. In theory, samarium and cobalt can be cut into shapes that can be cut by wire cutting, without considering magnetization and larger size. Samarium cobalt magnet, corrosion resistance is good, generally, do not need to carry out anti-corrosion plating or coating. In addition, the texture of samarium cobalt magnet is very brittle, so it is difficult to process small size or thin-walled products.

The neodymium magnet is a magnet product with wide application and rapid development. Neodymium iron boron has been widely used since its invention, and it has not been more than 20 years. Because of its high magnetic properties and processability, the price is not very high, so the application field expands rapidly. At present, the magnetic energy product of commercialized NdFeB can reach 50MGOe, which is 10 times that of ferrite. NdFeB is also a powder metallurgical product, and its processing method is similar to that of SmCo. At present, the highest working temperature of NdFeB is about 180 degrees Celsius. If it is used in harsh environments, it is generally recommended not to exceed 140 degrees Celsius. NdFeB is very susceptible to corrosion. Therefore, most of the finished products need to be electroplated or coated. Conventional surface treatments include nickel plating, zinc plating, aluminum plating, electrophoresis, etc. If working in a closed environment, phosphating can also be used. Because of the high magnetic properties of NdFeB, NdFeB has been used to replace other magnetic materials on many occasions to reduce the volume of products. If we use ferrite magnets, the size of mobile phones today will not be less than half a brick.
Samarium cobalt magnet and neodymium iron boron magnet have better processing performance. Therefore, the dimension tolerance of the product is much better than that of ferrite. General products, size tolerance can be achieved (+/-) 0.05 mm.

Aluminum-nickel-cobalt magnet has two processes: casting and sintering. AlNiCo magnets have a magnetic energy product of up to 9MGOe, which has the greatest characteristic of high-temperature resistance and working temperature of 550 degrees Celsius. However, Al-Ni-Co is very easy to demagnetize in reverse magnetic field. If you push two poles of Al, Ni, and Co together, the magnetic field of one of the magnets will be withdrawn or reversed. Therefore, it is not suitable to work in the reverse magnetic field (such as magnet rotor). Aluminum, nickel, and cobalt have high hardness. Although they can be ground and cut by wire, they are expensive. Generally supplied products, there are two kinds of ground or non-grinded. Aluminum, nickel, and cobalt are widely used in the sensor field.