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Gas-atomized Nd-Fe-B magnetic powders were subjected to magnetic pulse compaction, which is very high-energy compaction method, can be densified in a short time with various binder contents at different compaction pressures. The powders were rapidly forced together with in an abbreviated period, and formed a well-packed dense sample with full density during the magnetic pulse compaction process. The influence of density on the magnetic properties of the Nd-Fe- B magnet was investigated. The relative density increased with pressure and highest density of 6.9 g/cm3 was achieved at a consolidation pressure of 3 GPa. The optimized binder content and pressure were found to be 1 wt% and 3 GPa, respectively, for achieving the highest density. The remanence and maximum energy product of the Nd-Fe-B magnets gradually increased with increasing density. The significant improvement in density can effectively offers high remanence of 6.635 kG and maximum energy product of 8.5 MGOe.

The coarsening behavior of copper nanopowders (50–150 nm in size) during mechanical milling was investigated as a function of milling atmosphere and milling time. Pure copper powders were milled under argon and air atmospheres for up to 80 h and the crystal structure, microstructure, and composition of the milled powders were investigated. It was shown that on milling the powders for 80 h under air atmosphere, the particle size was in the range of 7 to 80 μm due to sphere-to-sphere and/or sphere-to-flake welding and from the aggregation of the copper particles during milling. On the other hand, the particle size was only 7 to 35 μm, when milled under argon atmosphere even after 80 h of milling. There was no difference either in the crystal structure or lattice parameter of the copper powder after milling in the two atmospheres. The powders got contaminated with oxygen; the oxygen content increased with increasing milling time, reaching up to 4.97 wt.% when milled in air for 80 h. The oxygen got incorporated into the copper powders to form oxide layers, which were broken down during milling and thus played an important role in determining the final particle size and microstructure of the powder. A viable explanation was provided to explain the differences in the microstructure and sizes of the powder particles milled under the argon and air atmospheres.

This study reports on the mechanochemical synthesis (MCS) and consolidation of nanostructured CeB6 powders of high purity. CeB6 powders were prepared via MCS by milling CeO2, B2O3 and Mg powders in a high-energy ball mill for different milling times. The effects of milling time on the formation, microstructure and thermal behaviour of the synthesized powders were investigated and the optimum MCS duration was determined. Purified powders were obtained after HCl leaching by removing MgO by-product. The prepared powders were characterized by a number of techniques including X-ray diffraction, stereomicroscopy, scanning and transmission electron microscopy coupled with energy dispersive spectrometry, differential scanning calorimetry, atomic absorption spectrometry, particle size analysis, surface area analysis and vibrating sample magnetometry. The high-purity CeB6 powders having an average particle size of 86 nm were consolidated by cold-pressing followed by pressureless sintering at 1700 degrees C for 5 h. The bulk CeB6 specimen was investigated for its microstructure, density, electrical resistivity, surface roughness and some mechanical properties (microhardness and wear behaviour). The relative density, electrical resistivity, microhardness and wear rate of the bulk CeB6 were determined as 95.2% TD, 57.50 mu W.cm, 11.65 GPa and 1.46 x 10(-4) mm(3)/N.m, respectively., Scientific and Technological Research Council of Turkey (TÜBİTAK); Synthesis of Lanthanum, Cerium and Samarium Borides by Solid-State Reaction at Room Temperature; İstanbul Technical University Scientific Research Projects; Mechanochemical Synthesis and Characterization of Some Rare-Earth Metal Borides