Because of its name, high-temperature resistant magnets must be able to operate at high temperatures. Generally speaking, the magnetic strength of a magnet is inversely proportional to its temperature. How to say it, that is, the stronger the magnetism, the weaker its temperature resistance, such as neodymium iron. Boron (220), samarium cobalt (250-350); the weaker the magnetism, the higher the temperature resistance, such as ferrite (500-600), aluminum nickel cobalt (500-600). Normally, NdFeB is not resistant to high temperatures, because the extreme working temperature of NdFeB ranges from 80°C to 220°C. If you need to withstand higher temperatures, you should consider using samarium cobalt or others.
High temperature magnet
The following introduces the high temperature resistance of ferrite, neodymium iron boron, samarium cobalt, and aluminum nickel cobalt.
The use temperature of ferrite is relatively high, and generally it can withstand a temperature of more than 200 degrees. The disadvantage is that the magnetic energy product is low, but the price is low.
The working temperature of neodymium iron boron is below 220 degrees, the magnetic energy product is the highest, the coercive force is the highest, but the temperature stability is not good, that is, it is not resistant to high temperatures. The disadvantage is that it is easy to oxidize (the surface needs to be electroplated). The price is moderate, so it is also widely used.
Samarium cobalt has high magnetic energy product, high coercivity, the highest operating temperature, up to 350 degrees, and good temperature stability. It is generally used in precision instruments and military industries. The disadvantage is that it is expensive.
In the AlNiCo magnetic energy product, the temperature stability is good, but the disadvantage is that the coercive force is extremely low, it is easy to be demagnetized, and the price is moderate.
The question is, what is the price of high-temperature magnets?
If you consult some magnet manufacturers in this way, it is estimated that you will not be able to give a quotation. First of all, how high is the high temperature resistance you said? How much is the order quantity? Does the surface need to be plated? What kind of magnetization direction? A requirement for tolerances and so on. If a specification and other requirements are determined, the required high temperature resistance is higher, and the price may be more expensive, because the material is different, the price is naturally different.
You may ask, the brand on the Internet is so cheap, why is it so expensive, the prices on the Internet are generally just for reference, and some are just to attract eyeballs, subject to your actual situation.
What is the difference between high temperature resistant and non-high temperature resistant appearance?
From the appearance point of view, there is no difference. For this coercive force experiment, the magnet is heated to 120°C, and then placed in the energized coil to maintain the temperature. The magnetic field opposite to the magnet itself will be generated when it is energized, and it must not exceed the inner magnet. Coercive force, and then let the magnet cool down. If the magnetic force drops significantly after the magnet cools, it is not a high-temperature resistant model.
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