Alnico magnets. These magnets, made by casting or sintering, are made from Aluminium, Nickel, Cobalt and Iron. Whilst they have, by now, mostly been superceded by rare earth magnets, they are particularly in demand for their consistent magnetic performance over a large temperature range (-40°C to 525°C) and corrosion resistance. Typical Bhmax range 9.0 to 72 kJ/m³ (1.13 to 9.0 MGOe)