1.Product Introduction

Neodymium magnet products can be divided into bonded neodymium magnets, hot-pressed neodymium magnets and sintered neodymium magnets according to different production processes. Due to different production processes, they have great differences in magnetic properties, processing and applications.

①Hot-pressed Neodymium magnet

Hot-pressed neodymium magnets can achieve magnetic properties similar to sintered neodymium iron boron without adding heavy rare earth elements. The product has the advantages of high density, good corrosion resistance, and high coercivity, but its mechanical properties are not good and due to patent monopoly, the processing cost is high.Currently, only a few companies in the world have the production technology for hot-pressed neodymium magnets.

②Bonded Neodymium magnet

In the 1970s, due to the immature technology of sintered neodymium magnets, it was difficult to precisely process them into special shapes. Moreover, problems such as cracking and breakage are prone to occur during processing, which limits its application.To solve this problem, magnet manufacturers pulverized permanent magnets, mixed them with plastic, and pressed them in a magnetic field. This was the original production method of bonded neodymium magnets. Since then, bonded neodymium magnets have been widely used due to their low cost, high dimensional accuracy, large shape freedom, good mechanical strength, and light weight.

③Sintered neodymium magnet

Sintered neodymium magnets are a compound composed of three elements: Nd, Fe and B. Sintered neodymium magnets are “magnetic kings” with wide application range, superior magnetic properties and high cost performance among magnetic materials. They are widely used in industry, manufacturing and high-tech industries.Sintered NdFeB permanent magnets are produced using powder metallurgy and have multiple manufacturing steps. Each link must lay a solid foundation for the next link. Once a process link fails to meet the requirements, the final product may not meet the target performance requirements and be scrapped.

2.Product Analysis

①Hot-pressed neodymium magnet

Advantages: It can achieve extremely high magnetic performance without using heavy rare earth elements. The maximum energy product of the current product can reach 43MGOe. Low losses during processing.

Disadvantages: Currently it can only be made into a ring shape, which greatly limits the application range of hot-pressed neodymium magnets. Currently it is mainly used in automotive EPS motors and other fields.Due to the high technical barriers to hot-pressed NdFeB, currently only Daido Electronics of Japan has achieved mass production in the world. This technology monopoly makes the product very expensive.

②Bonded Neodymium magnet

Advantages: The product has high dimensional accuracy and flexible shape. Contains no heavy rare earth elements and has lower unit cost. One-piece molding, low loss during processing.

Disadvantages: The magnetic performance is low, and the maximum energy product of the current product is about 12MGOe. The  coercivity and operating temperature are low.

③Sintered neodymium magnet

Advantages:Extremely high magnetic properties.It is the magnetic material with the highest magnetic performance at present. The maximum energy product is as high as 55MGOe (N54).

Disadvantages: In order to adapt to high-temperature working environments, heavy rare earth elements are added to some high-performance sintered neodymium magnets to increase the  coercivity and working temperature of the magnets. However, this will lead to higher unit costs of the product.The production process is complicated, the processing loss is high and the yield is affected.

3.Product Application Fields：Sintered, Hot-pressed and Bonded

According to the performance and cost of the three types of products, they have applications in different fields.

Hot-pressed neodymium magnets can only be made into ring shapes, which limits their application scope. Currently, they are mainly used in the field of automotive EPS motors. Compared with sintered NdFeB, the market size of hot-pressed NdFeB is extremely small, so the impact on the market demand for sintered NdFeB magnets is also relatively small.

The magnetic properties of bonded neodymium magnets are poor, so they are mainly used in fields that do not require high magnet performance, such as hard disk and optical drive spindle motors and smaller power micro motors.

Sintered neodymium magnets have the best magnetic properties among all magnet categories and are more commonly used in drive motors, magnetic resonance imaging machines and other fields that require higher power.

4.Conclusion

We hope this article helped you understand the product types of neodymium magnets.

If you are interested in the sintered neodymium magnets we provide, you can view our related product information or contact us directly.Contact | HQ Magnet (hq-magnet.com)

The production process of sintered neodymium magnets:Sintering Process for Neodymium Magnets – YouTube