Samarium cobalt permanent magnet material

Samarium cobalt permanent magnet material overview

Samarium cobalt permanent magnet material is a kind of rare earth permanent magnet, which is made by the ratio of rare earth elements samarium, cobalt and other elements. It has high magnetic energy product and extremely low temperature coefficient, and the highest working temperature can reach 350℃.  Compared with Ndfeb, samarium cobalt permanent magnet is more suitable for working in high temperature environment, it can still maintain good temperature stability and chemical stability above 180℃, at the same time it has strong corrosion resistance and oxidation resistance,  It is widely used in aerospace, national defense, microwave devices, communications, medical equipment, various magnetic transmission devices, sensors, magnetic processors, motors, magnetic cranes and so on.

Production process of samarium cobalt  

The main industrial manufacturing processes of rare earth cobalt permanent magnet materials are powder metallurgy and bonding.  

Powder metallurgy (sintering) is the main manufacturing method of high-performance rare earth cobalt permanent magnet materials, and its typical process flow is shown in the figure below.  

Bonding method is a manufacturing process in which rare earth cobalt permanent magnet powder is used as raw material and the adhesive (usually organic adhesive) is mixed, pressed, extruded or injection molding, and then cured. Permanent magnet elements with complex shapes can be obtained directly.

Samarium cobalt and Ndfeb difference  

1. Different ingredients  

In ndfeb permanent magnet, neodymium accounts for 29%~32.5%, iron 64%~69%, boron 1.1%~1.2%, and dysprosium, terbium, niobium, copper and other elements are added.  

Samarium cobalt magnet, take 2:17 type as an example, the rare earth samarium metal accounted for 23%~28%, metal cobalt accounted for 48%~52%, metal element iron accounted for 14%~17%, and a small amount of copper, zirconium and other elements.  

2. Different performance and price  

It can be found from the previous performance table that the overall magnetic property of samarium cobalt permanent magnet is lower than ndfeb permanent magnet.  In addition, samarium cobalt magnets of the same performance size are slightly more expensive than Ndfeb magnets.  From the proportion of metal elements, we can see that the iron content of Ndfeb is the highest, while the samarium and cobalt content of samarium cobalt magnets account for about 70%, so it is reasonable to be expensive ~  

3. High temperature resistance, oxidation resistance, corrosion resistance  

The working temperature of ndfeb permanent magnet is between 80℃ and 200℃, while the working temperature of samarium cobalt permanent magnet is between 250℃ and 350℃.  

The iron content of Ndfeb magnet is high, so it is easy to be oxidized and corroded. The surface treatment process is essential. The service life of the magnet largely depends on the effect of the coating.  Samarium cobalt magnets, on the other hand, have less iron content and are basically metal elements that are not easily oxidized and corroded, so they generally do not require surface treatment, except for harsh working conditions or electroplating to beautify the appearance.