alnico magnets are fored by casting or powder metallurgical processes. Both of them have good corrosion resistance charagteristic, no coating is needed for surface protection. Alnico remains the workhorse of the permanent magnet industry and can be relied upon to deliver impressive flux density at an economical price. Alnico also boasts the lowest temperature coefficient of any commercial magnet material(. 02% per degree centigrade) allowing for excellent stability over a wide temperature range. The maximun working temperature can be higher than 400 degree for this magnets.