Shinya Sakurada

Structural and magnetic properties of rapidly quenched (R,Zr)(Fe,Co)10Nx (R=Nd,Sm)

The structural and magnetic properties of (R,Zr)(Fe,Co)10(R=Nd,Sm) prepared by the rapid‐quenching method have been investigated. The presence of zirconium makes it possible to realize a TbCu7‐type crystal structure with a high c/a ratio of more than 0.87, while the same crystal structure has a c/a ratio of just 0.84–0.85 in the zirconium‐free case. The saturation magnetization of crystals having such a high c/a ratio as 0.87 exceeds 1.7 T at room temperature. These materials can be nitrogenated, and remarkable enhancement of magnetocrystalline anisotropy by nitrogenation can be seen in the case of Sm. The magnetic hardening of these nitrogenated materials can be achieved by annealing before nitrogenation. The highest value of (BH)max obtained so far for the nitrogenated materials is 144 kJ/m3 (18.0 MGOe). The iHc and Br values for this sample are 503 kA/m (6.3 kOe) and 1.08 T, respectively.

Effects of Solution Treated Temperature on the Structural and Magnetic Properties of Iron-Rich

The effects of solution-treatment temperature on the phase constitution, microstructure and magnetic properties of Sm(Co_bal.Fe_0.35Cu_0.06Zr_0.018)_7.8 were investigated systematically. The formation of Sm₂Co₇ around the Sm₂O₃ was confirmed and the volume fraction of Sm₂Co₇ increases with decreasing solution-treatment temperature. An area without cellular structure was observed around the Sm₂Co₇ phase in aged specimens solution treated at 1403 K. Thus, it was found that precipitation of Sm₂Co₇ phase prevents the formation of cellular structure during aging treatment. The coercivity of those magnets was less than 600 kA/m. On the other hand, the obvious formation of cellular structure was confirmed in the case of solution treatment at 1423 K and these magnets showed high coercivity of more than 1000 kA/m. The magnetic properties of M_r = 1.22 T and H_cJ = 1011 kA/m have been obtained for Sm(Co_bal.Fe_0.35Cu_0.06Zr_0.018)7.8 by solution treatment at 1423 K.

{\rm Sm}({\rm CoFeCuZr})_{\rm Z}

Abstract RFe 10 Si 2 (RLa, Pr, Nd, Sm, Gd, Er and Zr compounds were synthesized by the rapid quench method. The ThMn 12 structure can be obtained in the RFe 10 Si 2 system containing RSm, Gd and Er, while the NaZn 13 structure can be obtained in the system containing RLa, Pr and Nd. It has also been found that Nd 1− x Zr x Fe 10 Si 2 ( x = 0.25, 0.5 and 0.75) crystallized in the ThMn 12 structure. The factors which control the formation of ThMn 12 and NaZn 13 structures in the RFe 10 Si 2 system are discussed with respect to the atomic radius of the rare earth site element.

Sintered Magnet

Dependence of magnetic properties and microstructure on boron additions for nitrogenated (Sm,Zr)(Fe,Co)/sub 9/ alloys fabricated by rapidly quenching was investigated. The condition for getting high (BH)/sub max/ with high /sub i/H/sub c/ is to produce an amorphous phase in the rapidly quenched sample because it leads to the precipitation of uniform and fine grains by the annealing above their crystallization temperature. The role of boron is to form the amorphous phase easily by rapidly quenching. High (BH)/sub max/ of about 20 MGOe with high /sub i/H/sub c/ of 9.6 kOe was obtained for nitrogenated (Sm/sub 0.7/Zr/sub 0.3/)(Fe/sub 0.95/Co/sub 0.05/)/sub 9/B/sub 0.1/. High (BH)/sub max/ of 13.0 MGOe was also attained as an isotropic resin bonded magnet with density of 6.2 g/cm/sup 3/.

A study on the formation of ThMn12 and NaZn13 structures in RFe10Si2

In this study, we investigated intermediate-heat treatment (IHT) at temperatures between those of sintering and solution treatment, and evaluated the effects on the macrostructure, microstructure, and magnetic properties of Sm(Cobal.Fe0.35Cu0.06Zr0.018)7.8. We found that squareness was clearly improved by adopting the IHT, which promotes grain growth. These results indicate that reducing the fraction of grain boundaries by increasing the grain size affects the behavior of domain-wall motion. Magnetic properties of Mr 1.22 T, HcJ 1580 kA/m, and (BH)max 282 kJ/m3 (>35 MGOe) were obtained for Sm(Cobal.Fe0.35Cu0.06Zr0.018)7.8 subjected to IHT at 1453 K.

Magnetic properties and microstructure of rapidly quenched SmZrFeCoN magnets

The structural and magnetic properties of rapidly quenched (Sm,Zr)(Fe,Co)11Bx (x = 0–1) ribbons have been studied. Boron addition increases the amorphous forming ability and fine-uniform TbCu7 grains were obtained by rapid quenching with relatively low roll surface velocity. The magnetic properties of Mr = 0.99 T and Hcj = 273 kA m− 1 were obtained for (Sm0.7Zr0.3)(Fe0.8Co0.2)11B0.7 ribbons fabricated by rapid quenching with a surface velocity of 20 ms− 1 and subsequent annealing at 998 K for 0.9 ks.

Influence of intermediate-heat treatment on the structure and magnetic properties of iron-rich Sm(CoFeCuZr)Z sintered magnets

The potential for high conversion efficiency of the homojunction Cu(In, Ga)Se2 (CIGS) solar cells was examined by device simulations and experimental approaches. The simulation results showed that many electrons in n-CIGS layers could compensate to some extent for the existence of interface states at i-ZnO/n-CIGS interfaces in the homojunction structure. In the case of using the partial electrolyte treatments of CIGS films to produce the n-type doping, the concentrations of the Cd dopants in the n-CIGS layer were 1016 cm-2. The conversion efficiency of 17.2% for this homojunction CIGS solar cell was obtained.