To elucidate the predominant factor determining the soft magnetic properties of nearly zero-magnetostrictive amorphous alloys, the effects of processing conditions on the magnetic properties were investigated.
And the effects of Nb substitution instead of Co on the crystallization temperature (Tx), hardness and magnetic properties were investigated.
Also, the conventional and the magentic field annealing were done to obtain the optimum heat treatment condition in each composition and to explain the related phenomena caused from Nb addition.
Amorphous alloy ribbon of about 1 mm width was made by the single-roll casting method.
The coercive force (Hc) did not vary with the roll rotating speed and melt temperature, and was proportional to the ratio of surface roughness to ribbon thickness, $\delta$T/T.
Thus, it could be concluded that domain wall pinning exerts a major role in determining the magnitude of Hc.
Tx and the hardness increased and the soft magnetic properties were improved as Nb contents increased. This alloy seems to approach the zero $\lambda_s$, value as Nb contents increase.
By annealing in the temperature range between Tc and Tx and by magnetic field annealing at any temperature, these alloys became magnetically softer.
It was also shown that Nb addition mitigates the formation of preferred domain orientation in magnetic field annealing and domain-wall pinning effect caused from annealing under Tc without field.
