Magnetic property enhancement of modified nanocrystalline ZrCo$_{5}$-based magnets*

The metastable ZrCo$_{5}$ compound may be a good candidate for the development of rare-earth-free high-performance hard magnetic materials because of its high magnetocrystalline anisotropy field. Melt spinning is a good approach to synthesize metastable phase because of its high quench rate. In this work, the effect of Zr and Fe addition on structure and magnetic properties of melt-spun nanocrystalline Zr$_{1+x}$Co$_{5}$(0--0.3) alloys has been investigated. All the samples consist of orthorhombic ZrCo$_{5}$ hard magnetic and Co/Zr$_{6}$Co$_{23}$ soft magnetic phases. Proper Zr addition causes nanostructure refinement and the increase of the hard magnetic phase content, which strengthens intergrain exchange coupling. As a result, coercivity and maximum energy product of ZrCo$_{5}$-based magnet are significantly enhanced. The best magnetic properties: $_{i}$H$_{c}$ = 2.8 kOe, (BH)$_{max}$ = 4MGOe, which is the best value among Co-Zr binary alloys, are achieved in Zr$_{1.1}$Co$_{5}$. The temperature coefficient of its coercivity between 10 and 380K is -0.05{\%}/K. The saturation magnetization of nanocrystalline Zr$_{1.1}$Co$_{5}$ is greatly increased due to 16 at{\%} Fe addition.