Structure and magnetism of Fe-26Cr-12Co-1Si ribbon magnets

Abstract This paper provides a new and simple way to obtain thinner ribbon magnets with hard magnetic properties. Fe-26Cr-12Co-1Si ribbons were fabricated by melt-spinning at a speed of 40 m/s and followed by multi-step ageing at 647–540 °C. Phase composition, microstructure, domain structure and magnetic properties of the ribbons were studied. It has been found that the phase transformation of γ+α→α 1 +α 2 + Fe(Si,M) 2 +σ and element diffusion are dominant respectively during the first stage ageing and later multi-step ageing. Consequently, a spinodal structure containing a majority of α 1 and small amount of α 2 is formed. Model for microstructure and magnetic structure evolution of the ribbons in the ageing process is established. Hc as high as 1026.6 Oe and Br of 7274.8 Gs can be achieved in the seven-step aged ribbons. Such outstanding magnetic performances may be attributed to five main microstructural and magnetic structural factors.