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The microstructure and the magnetic properties of nanocomposite (Nd,Tb)5.5(Fe,Cr,M)76.5B18 (M=Co,Si) magnetic materials have been investigated. The samples were prepared by splat cooling and subsequent fast annealing treatment between 700 and 800 °C in order to develop a nanocrystalline microstructure. Optimum magnetic properties are found in samples with 3 at % Cr. A higher Cr content results in an increase of the coercive field but also in a decrease of both remanence and saturation magnetization. The magnetic properties of splat cooled materials with 3 at % Cr can be improved by the substitution of Co or (Co,Si). Splat cooled flakes with 2.5 at % Co and 0.5 at % Si show a coercive field Hc of 551 kA/m and a remanence μ0Mr of 0.91 T. After optimized annealing the magnetic materials consist of a homogeneous microstructure of Fe3B and (Nd,Tb)2Fe14B grains with a grain size in the range of 10–30 nm. The substitution of Co leads to a slight coarsening of the grain size.

High energy density magnets >400 kJ/m3 are increasingly used in many applications. Conventional casting techniques for sintered magnets reveal the formation of a high quantity of α-Fe and large Nd-rich regions. New techniques, like strip casting, produce homogeneous and fine scaled microstructures and are already used for producing high (BH)max magnets. The fast cooling rate during strip casting suppresses the formation of α-Fe dendrites and of large Nd-rich pockets. Directional solidification causes a formation of columnar grains containing a typical arrangement of hard magnetic Nd2Fe14B regions and Nd-rich regions. The Nd regions occur as intragranular platelets as well as intergranular phases. Intragranular lamellae show a periodicity which corresponds to a eutectoidal solidification according to the composition of the liquid and are directed parallel to the temperature gradient during solidification. The lamellae show an average width of 150 nm, a spacing of 3 μm, and a length up to the size of the hard magnetic grains. The fine separation of the hard magnetic and Nd phases is advantageous for the milling of the alloy after hydrogen decripitation and improves sinterability of magnets. Although the microstructure of strip cast alloys is much finer than that of ordinary cast alloys, the alignment of the powder is not deteriorated and Br is not reduced due to a sufficient large interlamellar spacing between the Nd-rich platelets that enables the formation of single crystal powder particles after milling.

Sintered magnets were prepared from jet‐milled and hydrogen‐decrepitated jet‐milled Nd‐Fe‐B:(Cu,Nb) powder. The HD process started after heating the cast material up to 200 °C. A single‐step annealing treatment at 525 °C improved the magnetic properties of all samples. Magnets prepared from the jet‐milled powder required a short time sintering (

The hard magnetic properties of hot‐worked R‐Fe‐B permanent magnets are improved by the addition of a minor amount of Cu (up to 2 at. %). Transmission electron microscope investigations show that the reason for the increase of the coercivity is the fact that Cu is mainly dissolved in the intergranular region separating the hard magnetic 2:14:1 grains. The results obtained are similar in Nd‐Fe‐B:Cu and Pr‐Fe‐B:Cu magnets. The intergranular region has been observed to consist of a eutectic consisting of two phases: the Nd‐or Pr‐rich phase and the orthorhombic NdCu‐ or PrCu‐phase. This corresponds to the eutectic decomposition of the liquid intergranular phase during cooling. It is suggested that the decrease of the melting temperature of the intergranular phase leads to a better wetting behavior and separation of the hard magnetic grains, and therefore to an enhancement of the coercivity.

We present a focused ion beam based technique for the synthesis of nanowires in room temperature ambient without using any additional material source. Based on the idea of a catalytic approach gallium antimonide and antimony nanowires were grown with diameters of about 20nm. We suppose that the intense focused ion beam exposure forms catalytic particles alloyed by the constituents of the growing nanowire in situ. In contrast to a broad class of techniques for nanowire growth neither heating of the sample nor any additional material source is required, thereby being compatible with on-chip microelectronics.