AlNiCo magnets (also called Aluminum-Nickel-Cobalt magnets) are consist of Al (aluminium), Ni (nickel), Co (cobalt) and other elements like Cu (Cooper) and Ti (Titanium), they are part of permanent magnet family, they are the most versatile magnets available and can be made into very complicate shapes which are not possible for other magnets.
The advantages of AlNiCo magnets are: excellent temperature stability (max. working temperature up to 500⁰C), high residual induction, and relatively high energies. AlNiCo magnets are brittle and with low coercive force, special packaging way should be processed in order to make sure the safety and avoid demagnetization during shipping.
Grades Of Cast AlNiCo Magnets
Grades Of Sintered AlNiCo Magnets
AlNiCo magnets are produced by casting or sintering process, the magnetic properties and physical properties are slightly different.
Cast AlNiCo magnets are made from metal alloy melted and poured into a mold, after various heat-treated and cooled, a rough ground magnet with a dark gray color will be formed and solidified, then it can be machined and polished with a shiny appearance.
Sintered AlNiCo magnets are made from fine AlNiCo powder compacted into a die and pressed under tons of pressure, then sintered and cooled into a solid magnet in a hydrogen atmosphere.
Alnico magnets are hard and brittle, they are easily chipping and cracking, so special machining techniques and careful handling must be taken care when machine them.
Magnetizing & Surface treatment
There are anisotropic and isotropic materials of AlNiCo magnets, anisotropic magnets are treated and cooled in a magnetic field, then oriented with a preferred magnetic direction with maximum magnetic direction; isotropic magnet are not treated in a magnetic field, the magnets can be magnetized a all direction with same magnetic properties.
Alnico magnets are with excellent corrosion resistant, so surface coatings like NiCuNi, Zn are not necessary, they can be painted with color for educational or other purposes if required.
AlNiCo magnets are widely used for many applications especially which require high operating temperatures, the most common applications are electric motors, meters, guitar pickups, instrumentation, microphones, sensors, bearings, actuators, microwave devices, while also other applications like holding magnets, separators, magnetos, electron tubes, receivers, controls, relays, loudspeakers, security systems, cow magnets, radar, traveling wave tubes and more.