论文信息 - Mechanically milled nanostructured (Sm,Pr)12.5Co85.5Zr2 magnets with TbCu7 structure

Mechanically milled nanostructured (Sm,Pr)12.5Co85.5Zr2 magnets with TbCu7 structure

Nanostructured (Sm,Pr)(Co,Zr) magnets with the TbCu7-type structure have been synthesized by mechanically milling (Sm1−xPrx)12.5Co85.5Zr2 alloys (0⩽x⩽0.8) followed by appropriate annealing. Magnetic properties, structure, and microstructure have been investigated. It is found that single-phase (Sm,Pr)(Co,Zr)7 magnets with the TbCu7 structure and with nanoscale grain size (14–19 nm) form in the whole composition range. Intrinsic coercivity Hci decreases from 20.7 to 5.6 kOe with increasing Pr content from 0 to 0.8, while energy products (BH)max shows an optimum value of 12.6 MGOe (Hci of 17.9 kOe) at x=0.2 due to increase in remanent magnetization. Remanence ratio is observed in the range of 0.64–0.69, with an optimum value of ∼0.69 at x=0.3. The high coercivity is ascribed to the formation of nanocrystalline (Sm,Pr)(Co,Zr)7 phase of the TbCu7-type structure with large anisotropy, and the remanence enhancement may result from the exchange-coupling interactions between nanosized (Sm,Pr)(Co,Zr)7 grains. The ...

D. Sellmyer | Jian Zhou | Hong Tang

[1] G. Hadjipanayis,et al. Coercivity in mechanically milled Pr–Co–Zr powders with TbCu7 structure , 2000 .

[2] J. Liu,et al. Structure and magnetic properties of SmCo7−xTix with TbCu7-type structure , 2000 .

[3] G. Hadjipanayis,et al. Magnetic properties and microstructure of mechanically milled Sm2(Co,M)17-based powders with M=Zr, Hf, Nb, V, Ti, Cr, Cu and Fe , 2000 .

[4] Y. Liu,et al. Processing and Hard Magnetic Properties of Nanocrystalline Sm(Co,Zr) 7 Magnet Powders , 2000 .

[5] G. Hadjipanayis. Nanophase hard magnets , 1999 .

[6] M. McHenry,et al. STRUCTURE AND MAGNETIC PROPERTIES OF RCO7-XZRX(R=PR OR ER, X=0-0.8) , 1999 .

[7] R. Street,et al. Mechanically alloyed nanocomposite magnets (invited) , 1998 .

[8] M. McHenry,et al. Structure and magnetic properties of SmCo7−xZrx alloys (x=0–0.8) , 1998 .

[9] K. Strnat,et al. Demagnetization curves of four rare‐earth‐cobalt magnet types at temperatures 300–1000 K , 1982 .

[10] V. Pecharsky,et al. Handbook on the physics and chemistry of rare earths , 1979 .

[11] B. A. Calhoun,et al. Ferromagnetic materials , 1955 .