Effect of Ga addition on the microstructure and magnetic properties of melt-spun (Nd0.8Ce0.2)13.8Fe68.96-xGaxCo11.49B5.74 alloys

The effects of Ga addition on the magnetic properties and microstructure of (Nd0.8Ce0.2)(13.8)Fe68.96-xGaxCo11.49B5.74 ribbons are investigated in this paper. The results indicate that the Ga doping is significantly effective in increasing the coercivity H-cj of the samples being improved from 15.93 kOe to 19.19 kOe. The XRD patterns show that the Ga addition reduces the amount of soft magnetic alpha-Fe phase. The highest positive peak in Henkel plot is obtained by 0.5 at% Ga doping, which indicates strongest intergranular exchange interaction. The best remanence J(r) (=) 7.6 kG, and maximum energy product (BH)(max) = 12.51 MGOe are obtained in (Nd0.8Ce0.2)(13.8)Fe68.46Ga0.5Co11.49B5.74 alloy ribbon. The Curie temperature (Tc) monotonically decreases from 674 K for the Ga free alloy to 667 K for 1.0 at% Ga doping. The improvement in magnetic properties can be attributed to the increase in volume fraction of the 2:14:1 main phase and grain refinement as a result of Ga doping.