Controlling the crystallization and magnetic properties of melt-spun Pr2Fe14B/α-Fe nanocomposites by Joule heating

Abstract

Pr 2 Fe 14 B/␣-Fe based nanocomposites have been prepared through crystallization of melt-spun amorphous Pr 7 Tb 1 Fe 85 Nb 0.5 Zr 0.5 B 6 ribbons by means of ac Joule heating while simultaneously monitoring room-temperature electrical resistance R. The R value shows a strong variation with respect to applied current I, and is closely related to the amorphous-to-nanocrystalline phase transformation. The curve of R versus I allows one to control the crystallization behavior during Joule heating and to identify the heat-treatment conditions for optimum magnetic properties. A coercivity of 550 kA/m and a maximum energy product of 128 kJ/m 3 have been obtained upon heating the amorphous ribbons at a current of 2.0 A. These properties are around 30% higher than the values of samples prepared by conventionally ͑furnace͒ annealed amorphous ribbons.

Explosive shock processing of Pr2Fe14B/α–Fe exchange-coupled nanocomposite bulk magnets

“…Nanocomposites with such characteristics have been recently shown to have significantly improved magnetic properties. [4][5][6][7][8] However, these nanocomposites have been typically produced in the form of powders or thin films, and there exist major obstacles in producing bulk nanocomposite magnets. Conventional sintering and hot-pressing methods, which are usually used to produce single-phase microcrystalline permanent magnets, are not favored in making bulk nanocomposite magnets because it is difficult to avoid grain growth during these processes.…”

High hard magnetic properties and cellular structure of nanocomposite magnet Nd4.5Fe73.8B18.5Cr0.5Co1.5Nb1Cu0.2

“…An additional merit is in the cost reduction due to the lower consumption of rare earth elements. For these remanence-enhanced materials, the studies on phase constitution of Fe 3 B/Nd 2 Fe 14 B [1,2], a-Fe(Co)/Nd 2 Fe 14 B, a-Fe/Pr 2 Fe 14 B [3][4][5][6] were reported. Recently, remanence enhancement was also observed in self-assembly FePt nanocomposite magnet [7] and in melt-spun FePtB magnets [8,9].…”

Optimization of the magnetic properties of nanostructured Y-Co-Fe alloys for permanent magnets

“…[14][15][16] Fig. 1 shows the influence of rapid thermal annealing temperature and time on (BH) max , σ max and µ 0 H c at room temperature.…”