Nd9Fe85-xTi4C2Bx (x=10–15) magnetic alloys were investigated by differential thermal analysis and X-ray diffraction analysis. The results showed that with the B content increasing from 10 at.% to 15 at.%, the liquidus temperatures TL of the alloys decreased from 1498.5 to 1472.5 K; the solidus temperatures TS of them increased from 1353.2 to 1358.3 K; and the nucleation undercooling of the alloy melts cooled at the rate of 40 K/min decreased from 122.8 to 95.9 K, resulting in the solidification structures consisting of Nd2Fe14B, Fe3B, α-Fe, Nd1.1Fe4B4 and TiC nanocrystallines. Furthermore, the Nd9Fe85-xTi4C2Bx (x=11, 13, 15) bulk alloys in sheet form with the thickness of 0.7 mm were prepared by copper mold suction casting and their solidification characteristics and solidification structures under sub-rapidly cooling rate were investigated. The results showed that partially amorphous structures were obtained in the as-cast bulk alloys and the amount of amorphous decreased with the increase of the B content. By annealing the as-cast bulk alloys at 923 K for 10 min, the nanocomposite microstructures composed with Nd2Fe14B, Fe3B and α-Fe nanocrystallines, which showed a single-phase hard magnetic behavior and enhanced magnetic properties, were achieved.DTA heating and cooling curves of Nd9Fe85–xTi4C2Bx (x=10–15) alloy ingots (at heating and cooling rate of 40 K/min) with marking of characteristic temperatures (Nd9Fe71Ti4C2B14)

The bulk nanocomposite magnets of Nd9Fe81–xTi4C2Nb4Bx (x=11, 13, 15) in sheet form with the thickness of 0.7 mm were prepared by copper mold suction casting and subsequently annealing. The microstructure evolution and magnetic properties of bulk magnets were studied. It was shown that the as-cast microstructure of bulk alloys were composed of Nd2Fe14B, α-Fe, Fe3B crystalline phases and an amorphous matrix, and that the glass formability of alloy was improved with increasing the B content. The DSC analysis showed that the as-cast bulk alloys had the crystallization behavior of a two-step process. After annealing at the temperatures which was 40–63 K higher than their onset temperatures of the second exothermic peak, Nd9Fe81–xTi4C2Nb4Bx (x=11, 13, 15) bulk alloys obtained a finely mixed structure which were composed of Nd2Fe14B, α-Fe, Fe3B, (Nb,Ti)C crystalline phases and a residual amorphous phase, whose magnetic properties were significantly enhanced. For the bulk magnets of Nd9Fe81–xTi4C2Nb4Bx (x=11, 13, 15), the optimal magnetic properties of Br=0.63 T, iHc=155.1 kA/m, (BH)max=18.73 kJ/m3 could be achieved when x=13 after annealing at 983 K for 10 min.Room temperature hysteresis loops of Nd9Fe81-xTi4C2Nb4Bx(x11, 13, 15) bulk samples aS-cast and annealed optimally

Amorphous (Nd,Pr)13Fe80Nb1B6 ribbons were crystallized at 670–730°C for 5–25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isothermal incubation time is 12, 5, and less than 5 min at 670, 700, and 730°C, respectively. High coercivities, with the maximum value of iHc = 1616 kA/m at 700°C for 19 min, measured by a physical property measurement system, are obtained in the crystallized ribbons. This is mainly attributed to the addition of Pr and Nb, because Pr2Fe14B has a higher anisotropic field than Nd2Fe14B, and Nb enriched in the grain boundary regions can not only reduce the exchange-coupling effects among hard grains, but also impede grain growth during the crystallization process. In addition, it should also be related to the characteristics of the furnace that the authors designed.