cobalt so common now - material

摘要

The use of an alloy of cobalt (5 mols.) and mixed heavy and light lanthanide elements (1-1.43 mols.) produces permanent magnets with thermally stable magnetic properties e.g. residual magnetism, coercive field strength saturating magnetism etc. The general formula for such magnetic alloys is Co5(LnhxLnll-x)n where Lnh is heavy lanthanide e.g. Cd, Tb, Dy, and Lnl is light lanthanide e.g. Y, La, Ce, Sm etc. or cerium-mixed metal, and where 0 x 1 and 1 = u =1.43. A typical example is Co5Sm1-xGdx, the choice of composition being actually governed by the temp. of use of the magnet, and the alloy proportions being appropriately adjusted.