The Alnico (Aluminum, Nickel, Cobalt) family was introduced in the 1930's. It's characterized by excellent temperature stability, high residual induction, relatively high energies and resistant to corrosion. These were the first materials specifically designed for permanent magnets to be used in meters and instruments commercially.
Alnico is vailable in both cast and sintered forms. Sintered Alnico offer slightly lower Magnetic properties but better mechanical characteristics than cast Alnico. These materials are brittle, hard and cannot effectively be machined by conventional techniques other than by grinding.