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What is the Strongest Permanent Magnet in High Temperature?

It is well known that N55 magnet is the strongest Permanent magnets at room working temperature. However, are N55 magnets still the strongest magnets if they work at high temperature like at 60℃, 80℃, 100℃, 150℃, 200℃, 250℃, 300℃ ? The answer is “No”.

Why N55 magnets are not the strongest magnets at high temperature?

Because N55 magnets will lose force when they work at more than 100℃ for some times.

What is the strongest permanent magnets at high temperature?

Before answering, we would like to show how many kinds of strong permanent magnets are there.

The first category is alloy permanent magnet materials, including rare earth permanent magnet materials (Neodymium Magnets (NdFeB), Samarium cobalt magnets (SmCo)) and Aluminum Nickel Cobalt Magnets (alnico).

Ferrite Magnets is the second type of permanent magnet material.

According to different production processes, they are divided into sintered ferrite magnets, bonded ferrite magnets and injection molding ferrite magnets. These three processes are divided into isotropic magnets and anisotropic magnets according to the different orientation of magnetic crystals.

Permanent magnets, also known as hard magnets that are not easy to lose magnetism and not easy to be magnetized. However, if the permanent magnet is heated beyond the Curie temperature or locates in the environment of reverse high magnetic field intensity, its magnetism will also decrease or disappear. The maximum working temperature of alnico permanent magnet is more than 550 ° C , Samarium cobalt magnet is more than 500° C and ferrite magnet is about 250 ° C , Neodymium magnet is about 60-260° C and rubber magnet are about 100° C , while the actual value will still vary according to the size and shape of the material.

Among the most popular strong permanent magnets, Neodymium Magnets have many different super power grades, which can work at different high temperature as listed in table No. 1 from Mag SPring.

Properties Remanence Coercive force Intrinsic coercive force Maximum energy product Working temp
Unit kGs T kOe kA/m MGOe kJ/m3
Nom. Min. Nom. Min. Nom. Min. Nom. Min. Nom. Min. Nom. Min.
No Grade kOe kA/m
1 N55 15 14.8 1.5 1.48 10.8 10 860 794 ≥11 ≥875 54.9 52 437 414 ≤60
2 N54M 14.8 14.5 1.48 1.45 13.6 13.2 1082 1050 ≥14 ≥1114 53.7 51.2 428 408 ≤80
3 N52H 14.5 14.2 1.45 1.42 13.6 13.2 1082 1050 ≥17 ≥1353 52 50 414 398 ≤100
4 N50SH 14.2 14 1.42 1.4 13.5 13.1 1074 1042 ≥20 ≥1595 50 48 398 383 ≤130
5 N50UH 14.2 13.9 1.42 1.39 13.5 13.1 1074 1042 ≥24 ≥1911 50 48 398 383 ≤150
6 N48EH 14 13.8 1.38 1.38 13.3 12.9 1059 1027 ≥30 ≥2388 48 46 383 367 ≤200
7 N45AH 13.5 13.3 1.35 1.33 12.6 12.2 1003 971 ≥33 ≥2626 45 43 358 342 ≤220
8 N40TH 12.7 12.4 1.27 1.24 12.1 11.8 971 939 ≥40 ≥3185 39 37 310 294 ≤240
9 N35RH 11.9 11.7 1.19 1.17 11.5 11 915 876 ≥45 ≥3583 35 33 279 263 ≤260

Table No. 1

What magnets will be strongest in high working temperaure ? 

Take an axially magnetized permanent magnet D10x10 for example, which is in a closed circle situation:

1. If working temperature is more than 550 ° C, the strongest permanent magnets will be AlNiCo Magnets .

2. If working temperature is more than 250-550 ° C, Samarium Cobalt Magnets will be the strongest permanent magnets. SmCO magnet with grade XGS26HT is the highest performance permanent magnets from 350 to 550° C,  and SmCO magnet with grade XGS32H Grade is the highest performance permanent magnets from 280 to 350° C;

3. If working temperature is more than 60-260 ° C, Neodymium permanent Magnets will be the strongest permanent magnets. N55 Neodymium Magnet is the strongest permanent magnets from 0° C to 60 ° C, N54M Neodymium magnet is the strongest permanent magnets from 60 to 80° C, N52H Neodymium Magnet is the strongest permanent magnets from 80 C to 100 ° C, N50SH Neodymium magnet is the strongest permanent magnets from 100 to 130° C; N50UH Neodymium Magnet is the strongest permanent magnets from 130 C to 150 ° C, N48EH Neodymium magnet is the  strongest permanent magnets from 150 to 180° C; N45AH Neodymium magnet is the  strongest permanent magnets from 180 to 220° C; N40TH Neodymium magnet is the strongest permanent magnets from 220 to 240° C; N35RH Neodymium magnet is the strongest permanent magnets from 240 to 260° C.

2022/4/8 Posted by Mag Spring® – Green magnetic solution expert

TAGS: What is the strongest permanent magnet in high temperatures?  N55  Magnets , strongest magnet in the world, strongest magnets, Neodymium Magnets, Samarium cobalt magnets, AlNiCo Magnets 

 

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