Investigation of Structure and Magnetic Properties of Rare Earth-Leaned Pr 2(Fe, Co) 14(C, B)-Type Nanocomposites

Abstract

The phase evolution and magnetic properties of Pr xFe 82-x-yTi yCo 10B 4C 4 (x=9–10.5; y=0, 2) melt-spun ribbons have been investigated. The effects of wheel speed and annealing on the crystallization and magnetic properties of the ribbons were emphatically discussed. It was found that Ti substitution enhances the glass forming ability of the Pr 2(Fe,Co) 14(C,B)-type ribbons. For the high wheel speed V s (18 m/s), the Ti-substitution ribbons consist of significant amorphous phase, and show a typical two-step magnetic behavior, while most of Ti-free ribbons are mainly composed of the crystallized 2:14:1, α-(Fe, Co) and 2:17 phases. With decrease in wheel speed, all these composition of ribbons are crystallized, and more magnetically hard 2:14:1 phase is formed in the ribbons. The content of metastable 2:17 phase in the ribbons decreases with increasing Pr and Ti substitution. A B r of 9.5 kG, i H c of 9.8 kOe, and ( BH) max of 16.0 MGOe were obtained in the as-spun Ti-substitution Pr 10.5Fe 69.5Ti 2Co 10B 4C4 ribbon prepared at V s=15 m/s. For all the as-spun Ti-free ribbons prepared at different wheel speed V s, the ( BH) max is lower than 10 MGOe owing to poor demagnetization-curve shape. Ti substitution also helps suppressing the grain growth of 2:17 phase during annealing process, and simultaneously, gently promoting the growth of magnetically hard 2:14:1 phase. Annealing treatment significantly improves the magnetic properties of the Ti-substitution ribbons with higher Pr content. No obvious promotion of magnetic properties was found in the Ti-free ribbons after annealing.