FAQ
 

NDFEB Magnets FAQ

1. What are rare earth magnets?

The term Rare Earth Magnets is used to refer to a group of magnetic materials whose alloys consist of one or more of the Rare Earth elements. These materials are characterized by exceptionally strong magnetic properties.

2. Coatings of Neodymium magnets

The coatings do not affect the magnetic strength or performance of the magnet.

Neodymium magnets are a composition of mostly Neodymium, Iron and Boron. If left exposed to the elements, the iron in the magnet will rust. To protect the magnet from corrosion and to strengthen the brittle magnet material, it is usually preferable for the magnet to be coated. There are a variety of options for coatings, but nickel is the most common and usually preferred. Our nickel plated magnets are actually triple plated with layers of nickel, copper, and nickel again. This triple coating makes our magnets much more durable than the more common single nickel plated magnets. Some other options for coating are zinc, tin, copper, epoxy, silver and gold. Our gold plated magnets are actually quadruple plated with nickel, copper, nickel and a top coating of gold.

3. What can Neodymium magnets do?

Magnets affect electrically charged particles and electrical conductors. Magnets have the ability transform electrical energy without losing their own energy. These effects can perform useful functions, for example:
Electrical-to-mechanical effects are key in the function of motors, loudspeakers, and equipment that requires charged particle deflection.
Mechanical-to-electrical effects are useful in generators, motors and microphones.
Mechanical-to-heat effects facilitate eddy current and hysteresis torque devices.
Mechanical-to-mechanical affects, Magnetic separators, Sensors.

Other effects of magnets include magneto-resistance and magnetic resonance.

4. How long do magnets hold their magnetic strength?

If the magnets are not subjected to external magnetic fields high enough to cause demagnetization - and/or - elevated temperatures above the advertised maximum use temperature the field will remain at or near as received. This could be expected last for the life of the application.

5. General information on Neodymium Iron Boron Magnet Materials

Sintered neodymium-iron-boron (Nd-Fe-B) magnets are the most powerful commercialized permanent magnets available today, with maximum energy product ranging from 26 MGOe to 52 MGOe. Nd-Fe-B is the third generation of permanent magnet developed in the 1980s. It has a combination of very high remanence and coercivity, and comes with a wide range of grades, sizes and shapes. With its excellent magnetic characteristics, abundant raw material and relatively low prices, Nd-Fe-B offers more flexibility in designing of new or replace the traditional magnet materials such as ceramic, Alnico and Sm-Co to achieve high efficiency, low cost and more compact devices.

A powder metallurgy process is used in producing sintered NdFeB magnets. Although sintered NdFeB is mechanically stronger than Sm-Co magnets and less brittle than other magnets, it should not be used as structural component. Selection of Nd-Fe-B is limited by temperature due to its irreversible loss and moderately high reversible temperature coefficient of Br and Hci. The maximum application temperature is 200 C for high coercivity grades. Nd-Fe-B magnets are more prone to oxidation than any other magnet alloys. If Nd-Fe-B magnet is to be exposed to humidity, chemically aggressive media such as acids, alkaline solutions salts and harmful gases, coating is recommended. It is not recommended in a hydrogen atmosphere.

Neodymium magnets are a member of the Rare Earth magnet family and are the most powerful permanent magnets in the world. They are also referred to as NdFeB magnets, or NIB, because they are composed mainly of Neodymium (Nd), Iron (Fe) and Boron (B).

6. Temperature constraints

The temperature coefficient of neodymium has triggered several grades to be developed to meet specific operating requirements. Please refer to our chart of magnetic properties to compare the characteristics of each grade. Before choosing a neodymium magnet be sure to consider your application㡯s maximum operating temperature.

7. What does 'orientation direction' mean?

Some magnets, called oriented or anisotropic magnets, have a preferred direction in which they should be magnetized. The 'orientation direction,' also known as an 'easy axis' or 'axis,' is the direction that achieves its maximum magnetism. Other magnets, called unoriented or isotropic magnets, can be magnetized in any direction.

8. What are magnetic poles?

All magnets have points, or poles, where their magnetic strength is concentrated. Those points are called poles. We label them north and south because suspended magnets orient along north-south planes. On different magnets, like poles repel each other, opposite poles attract. Are permanent magnets really permanent?

9. Do magnets get weaker? How?

Several factors can weaken the magnetism in a magnet. If a magnet is stored close to heat, strong electrical currents, other magnets, or radiation, it can lose its strength. Additionally, high humidity can corrode neodymium magnets. Demagnetization.
Rare Earth magnets have a high resistance to demagnetization, unlike most other types of magnets. They will not lose their magnetization around other magnets or if dropped. They will however, begin to lose strength if they are heated above their maximum operating temperature, which is 176F (80 C) for standard N grades. They will completely lose their magnetization if heated above their Curie temperature, which is 310F (590 C) for standard N grades. Some of our magnets are of high temperature material, which can withstand higher temperatures without losing strength.

10. Can magnets that have lost their magnetism be re-magnetized?

That depends on how the magnetism was lost. Usually magnets can regain their original strength unless theyve been exposed to extreme heat.

11. Can magnets be made stronger?

Once a magnet is fully magnetized, it cannot be made any stronger.

12. What materials can be used for magnetic shielding?

In general, magnetic field attenuation is a function of the permeability of the material. A better shielding material has high permeability per weight. For metallic foil and sheet, the most efficient shielding material is the 80 Nickel family (e.g., Molypermalloy), followed by the 50 Nickel alloys (e.g., Deltamax). The economical silicon-steel foils and sheets are also good shielding material when weight is not of a major issue.

13. Are there any regulations for shipping magnetized materials?

According to the United States Department of Transportation and the Office of Hazardous Materials Safety, it is against regulations to ship a magnet by air that maintains a field of more than 0.00525 gauss measured at 4.5 meters (15 feet) from any surface of the package. This is to prevent the magnet from interfering with the operation of the aircraft's navigational compass. There are no federal regulations that restrict the shipping of magnetized materials by ground transportation. Please check with your commercial carrier for additional specifics.

14. Magnetization

Neodymium magnets require extremely high magnetizing fields and particular consideration must be given to this when designing complex assemblies. Neodymium can be magnetized in any direction as long as it is aligned properly. In some instances multiple pole magnetization is not possible; when it is possible, special fixtures are required.

15. What information should I provide when ordering?

We will help you with your order. Usually we ask for the following information.
Material type and grade required.
Size and shape, if available, a sketch or drawing with dimensions and tolerances.
Max working temperature.
Delivered magnetized or unmagnetized? Magnetization direction?
Quantities required.
Coating required (if any).

Information on what you want to use the magnet for.

SMCO Magnets FAQ

1. On rare earth permanent magnetic material

There are two types of rare earth magnets available: Neodymium and Samarium Cobalt. They are called rare earth because their composition elements found in the 'Rare Earth' or Lanthanides portion of the Periodic Table of Elements.
Neodymium magnets (Nd-Fe-B) are composed of neodymium, iron, boron and a few transition metals. Samarium cobalt magnets (SmCo) are composed of samarium, cobalt and iron. These rare earth magnets are extremely strong for their small size, metallic in appearance and found in simple shapes such as rings, blocks and discs.
Due to their tremendously high energy level, Rare Earth magnet material is ideal for miniaturized applications. They offer high resistance to demagnetization and are recommended for applications with temperature ranges under 200oF. Raw Rare Earth magnets have a dull metallic appearance and tend to be very brittle. They can be ground, but caution must be exercised not to crush the material. Be aware of possible fire from the dust particles produced from grinding or cutting Rare Earth magnet materials.

2. whether have standard geometric tolerance? What is the best one we can do?

The following table is the standard geometric tolerance for general product

Deviation types

Check position

General dimension

Deviation value

Parallelism ∥

Processing surfaces

Any

Block ≥15*15 , Disc , Circular≥Φ15 , two surfaces≤0.1mm; Block <15*15 , Disc , Circular<Φ15 , two surfaces≤0.05mm

Perpendicularity ⊥

Processing surfaces

Any

General Disc , block 90°±0.5° , block ≤4*4*4mm , disc ≤Φ3.5mm , Circular , Radial90°±1

Coaxially ◎

Processing surfaces

Any

Tolerance R±0.1 , ◎≤0.2mm, Tolerance R±0.05 , ◎≤0.1mm

Symmetry

Processing surfaces

Any

General products 0.15mm , special products 0.2mm

flatness

Processing surfaces

Any

Block ≥15*15 , Disc≥Φ15 , ≤0.1mm , Circular≥Φ15 , ≤0.15mm
Block <15*15 , Disc≤0.15 , ≤0.05mm , Circular≥Φ15 , ≤0.1mm/p>

○Cylindrical

Processing surfaces

Any

≥Φ20mm: 0.1mm ; ≤Φ20mm: 0.05mm

Curve Profile○

Processing surfaces

Any

R±0.1, ≤0.1mm , R±0.05, ≤0.05mm

Remark: geometric tolerance according to the stander GB2828, AQL0.65(S-4) to sample.
We will determine the best geometric tolerance according to the specific products. Pls contact with your contact person when you have inquiry.

3. Is the magnet have the standard size?

No,usualy the magnet is customized.And we can support the customer with a about size design accord to their use sometimes.
And because of the limit of our ability,we can not produce all the product size,the available size pls find our normal size and shape on website.

4. the package methods, and which one is the best to protect the goods?

Our main package methods are including general bags packing, plastic tube packing, Vacuum packing, and skin packing. At the same time, we can order the custom-made packing method according to customer’s requirement.
All the package methods can protect the goods. The reason why they have different methods, Firstly, It is related with the mode of the customer use. Secondly, It is related with the dimension of products, For Example: It could not use the Plastic tube packing, or Vacuum packing. Which package is much suitable depend on the dimension of the products.

5.How to inspect the performance of roughcast?

① to sample the materials located in the front, middle and behind of whole sintered oven.
②take the test sample column (The dimension is around D10*15mm) in the block roughcast.
③ get the result to use the Automatic magnetic tester.
④ Analysis all data, then determine the material are qualified or not.

6.Could you produce the magnet which is in unsaturated magnetized condition? 

①the performance values of each batch of magnets will fluctuate within a certain range. The voltage is difficult to be adjusted under the unsaturated magnetized condition.
②The performance is unstable when the magnet are unsaturated magnetized. And it will change while using.

7. Why SmCo5 is much expensive than Sm2Co17?

Because cobalt content in SmCo5 is more than Sm2Co17, while cobalt is scarce in China, We need to import raw materials, the price is very expensive. Although the magnetic energy product of SmCo5 is lower than Sm2Co17, the price is higher than Sm2Co17.

8.Whether Samarium Cobalt magnets require plating or not? What kind of plating available?

The Samarium Cobalt magnets for its better corrosion resistance, does not require plating under normal circumstances, However, the product will be required plating, when some customers use samarium cobalt magnet as the outer parts, or in some harsh application environment.
We can provide plating types as below: zinc, nickel, silver, copper, chemical nickel, nickel + copper + nickel, nickel + gold, nickel + tin, epoxy .etc.

9. Whether Samarium cobalt magnets will rust or not?

Samarium cobalt magnets will rust since its composition contain iron element. However, it is not very serious rust phenomenon compared with NdFeB magnets, as SmCo magnets contain lower iron element than NdFeB. When SmCo magnets are used in sea water, it will produce some rust points on surface , but does not affect its performance and application.

10. How to deal with customer complaints?

After receiving customer complaints, Sales will immediately fill out the customer complaint information at the top of the " customer feedback Disposal Record ", identified the reasons by the QC department and fill out comments at the bottom of the " customer feedback Disposal Record," then reply customer with disposal suggestion and 8D report if necessary.

11. Why can not generally determine the magnetic properties by the surface Gaussian(surface Gaussian value) but only as a basic basis?

Because the surface Gaussian value is one point value measured by the Gauss Meter in contact with magnet surface. Measuring points can not cover the entire product surface, so it is not correct to take the value of one point to measure the value of entire surface. Moreover, about 2% error exist in each Gaussian meter. Also in the measurement process, it exist error as we can not find the two coincident points in the same product .Therefore, the surface Gaussian value is only a basic magnetic reference, that can not be used to determine product performance. Typically, we just take the magnetic flux performance to estimate eligibility of the product.

12. why are some unfilled corners on products?

The physical properties of samarium cobalt magnets are very brittle (even brittle than glass), even by tiny force it will cause a little chippings or unfilled corners on the edge part of the magnets. It requires more than a dozen procedures to make a product, that it is difficult to avoid the unfilled corners in processing or working in the inspection process. So, it must be kept in strict attention and careful protection, when processing, testing, transportation, or application, Nevertheless, small unfilled corners can not be avoided completely.

13. What is the different between SmCo5 and Sm2Co17?

①the way of representation is different: We use YX to represent the SmCo5, and YXG represent Sm2Co17.
② Different components: the main components of SmCo5 include samarium, cobalt, Pr. Or just pure Samarium, Cobalt; the main components of Sm2Co17 include samarium, cobalt, copper, iron, and zirconium;
③ Different physical characteristics: such as the maximum operating temperature of SmCo5 is 250 ℃; and the maximum operating temperature of Sm2Co17 is 350 ℃. But the physical specification of SmCo5 is better than Sm2Co17, SmCo5 is much easy to machine while Sm2Co17 is more brittle.

14. What is the maximum characteristic for the smco magnet?

The maximum cahracteristic for smco magnet is YXG32,and its characterisitc is: Br: 11,000-11,300Gs; bHc: 10,200-10,600Oe; iHc≥ 15,000Oe; (BH)max: 29-32MGOe.