An introduction to the effect of temperature on AlNiCo magnets
AlNiCo magnets, as described in previous articles, have good temperature resistance, and their magnetic properties vary minimally with temperature, making them ideal for temperature-sensitive applications. The reversible temperature coefficient of induction is -0.02%/°C, and the The reversible temperature coefficient of coercivity is +0.01%/°C. This makes Alnico the perfect choice for performance critical applications such as medical and military.
Elevated temperatures may cause some permanent loss of Alnico output, depending on the physical shape of the Alnico magnet and the shape of the BH curve, exceeding 530°C may permanently alter Alnico's metallurgical structure , resulting in a significant permanent and irreversible drop in yield.
When high temperatures are likely to occur with Alnico magnets, it is recommended to heat the magnets to 10 degrees or higher than the expected maximum temperature to condition Alnico magnets, but thermal cycling to temperatures below the conditioning temperature in the future will not cause a further permanent drop in output ( The only change in output will be reversible losses, which disappear as the magnet cools, which is determined by the temperature coefficient of AlNiCo).
It is not recommended to use Alnico magnets at temperatures above 525 or 550°C (550°C is 1022°F or 823 Kelvin) as this will result in permanent loss of magnetic output.
-75 degrees Celsius is considered a reasonably acceptable lower temperature for Alnico, although approximately 10% irreversible losses have been reported at -190 degrees Celsius, the actual loss is a function of the magnet geometry, the overall magnetic circuit and the shape of the BH curve.
Hunan Broad Permanent Magnet Co.,Ltd
Mr.Bade Wu
Tel: +86 731 89723018 M.P: 13974929339
Email: bade@bromag.com.cn
Add: 1218-1219, Building B, Accord International, No. 61 Lufeng Road, Changsha 410205 ,China
