Coercivity Enhancement in ${\rm Zr}_{2}{\rm Co}_{11}$ -Based Nanocrystalline Materials Due to Mo Addition

The Mo-content dependence of structure and magnetic properties of Zr₁₆Co_78-xMo_xSi₃B₃ ( x=0, 2, 3, 4, 5) nanocrystalline materials has been studied. The samples consist of hard-magnetic Zr₂Co₁₁ and soft-magnetic Co phases. The substitution of Mo for Co restrains the formation of Co, raises the content of Zr₂Co₁₁, and increases the mean grain size of Zr₂Co₁₁. Therefore, the coercive force of the sample increases with x. A coercive force of 7.9 kOe, which is a highest value reported among Zr-Co alloys, was achieved for x=5. The anisotropy field of Zr₂Co₁₁ remains almost unchanged with increasing Mo content.