Magnetic properties of melt-spun MM–Fe–B ribbons with different wheel speeds and mischmetal contents

In this study, the effect of wheel speed and mischmetal (MM) content on the magnetic properties of MMFeB ribbons was investigated. The samples were prepared via direct solidification technique. The nominal composition of the alloy ingots is MM _x Fe_92−x B₈ with x varying from 9 to 15 in steps of 2. Experimental results show the overall magnetic properties of the ribbons. Analysis of the results shows that the magnetic properties first improve and then degrade with the wheel speed and MM content increasing. Increase in MM content leads to better formation of crystal texture in the ribbons, indicating that the α-Fe phase might undermine the formation of crystal texture. Magnetic properties results show that the coercivity of the ribbons rises with an appropriate increase in both MM content and wheel speed during melt-spun process. The strongest magnetic properties of the ribbons (remanence of M _r = 0.72 T, intrinsic coercivity of H _cj = 352.58 kA·m⁻¹, and maximum energy product of (BH)_max = 72.14 kJ·m⁻³) are obtained for compositions where x = 13 and a wheel speed of v = 20 m·s⁻¹.

The variation in maximum remanence (M _r), coercivity (H _cj), and maximum energy product ((BH)_max) values were analyzed as a function of wheel speed for the MM₁₃Fe₇₉B₈ melt-spun ribbons. All of the ribbons’ magnetic properties (M _r, H _cj, and (BH)_max) first increase as the wheel speed increases up to 20 m·s⁻¹ and then decrease gradually. The best magnetic properties are obtained at a wheel speed of 20 m·s⁻¹, achieving M _r value of 0.72 T, H _cj value of 352.58 kA·m⁻¹, and (BH)_max value of 72.14 kJ·m⁻³.