Anisotropic Nd–Fe–B magnet powders can be produced by the hydrogenationdecomposition-desorption-recombination (HDDR) process from Nd–Fe–B–Co–M (M=Ga, Zr, Nb, Hf, and Ta) alloys. The present status of those HDDR bonded magnets made them are reviewed with regards to powder particle size dependence their magnetic properties, thermal stability, magnetization behavior. results a mechanistic study on recombination step also presented. properties anisotropic depend relatively little size. Bonded...

MgO insulation coating with thickness of ca. 50nm was evaporated on the surface iron powder and fabricated soft magnetic composite(SMC) low loss. The had greater heat resistance than conventional phosphate coating, which enabled stress relieving annealing at higher temperature (600C). Electrical properties SMC examined. electrical resistivity annealed 700C 21μΩm. loss 50Hz for Bm = 1.5T 5.34W, 40% same level laminated steel plate (t0.35). These results show that has enough adhesiveness to obtain

The hydrogenation-decomposition-desorption-recombination (HDDR) process is a unique method to produce anisotropic Nd/sub 2/Fe/sub 14/B-based magnet powder for bonded application. In this study, we studied the effect of appending intermediate Ar (IA) treatment, i.e., hydrogenated materials are annealed under an atmosphere before evacuation treatment in HDDR process, on magnetic properties powder. It was found that IA very effective enhance anisotropy optimum made from processed 12.6/Fe/sub...

Soft magnetic composites (SMC’s) are produced compacting iron powder coated with a thin insulator and then heat-treating the greens. In this study, to improve properties of SMC’s, formation heat resistant MgO insulation layer on particles was examined. It found that coating can be made by dry process two steps, i.e., oxidation particle surfaces reduction oxide magnesium vapor. The SMC fabricated from MgO-coated exhibits high resistivity even after treatment at 600, which leads low losses...

Nd12.6-xDyxFebal.CoyB6.2Zr0.1Ga0.3(x =0.3-1.9, y =5.8-18.3) alloys were processed by improved HDDR process with intermediate argon treatment and desorption under constant H2 pressure to increase remanence coercivity, respectively. In this study, we investigated effect of Co Dy contents on the magnetic properties powders. By process, powders containing 0.3 at.% 12 16 is increased a maximum 0.96 T, coercivity them 0.9 1.6 5.8 1570 kA/m. Undecomposed (Nd, Dy)2(Fe, Co)14B phase remains in...

We studied the magnetic properties of Nd-Dy-Fe-Co-B-Zr-Ga magnet powders produced by hydrogenation-decomposition-desorption-recombination (HDDR) process, using a hydrogen pressure 0.1 MPa. Magnet with iHC higher than 1200 kA/m were obtained from alloys Nd11.3Dy1.3Fe80-yCoyB7.0Zr0.1Ga0.3, y≤11.6 at%. It was found that annealing in an Ar atmosphere added after HD treatment HDDR process improved anisotropy powders. Typical this are as follows: Br=1.27T, iHc=1280 kA/m, (BH)max=283 kJ/m3, and β=-0.44%/°C.

Recent progress in hydrogenation-decomposition-desorption-recombination (HDDR) process technologies is described with regard to the commercial production of Nd-Fe-B magnet powders. The applications powders resin-bonded magnets and hot-pressed are also presented. HDDR reaction kinetics an essential factor for improvements magnetic properties Modified process, i.e., annealing decomposed alloys under Ar atmosphere, then evacuating them correct desorption rate, can enhance anisotropy...

Fully dense magnets prepared by hot pressing of the hydrogenation-decomposition-desorption-recombination (HDDR)-processed powders have very fine microstructures. We investigated magnetic properties and surface morphology machined HDDR thin pressed magnets. In performance magnets, it is hard to get influence thickness almost not damage roughness. The long-term stabilities were total irreversible flux loss a high coercivity magnet at 423 K was -1.3% after 1000 h. make possible stabilize Nd-Fe-B

It is well established that the hydrogenation-decomposition-desorption-recombination (HDDR) process can produce anisotropic Nd2Fe14B-based magnet powders having high coercivities. In this study, we investigated effects of intermediate argon (IA) treatment, where alloys are annealed under atmosphere after hydrogenation in HDDR process, on magnetic properties Nd12.6Febal.Co17.4B6.5Zr0.1Ga0.3 powders. was found anisotropy improved with IA treatment time. On other hand, their coercivities...

Effects of aging treatments a precipitation hardened type magnetic alloy, Sm(Co <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.67</inf> Fe xmlns:xlink="http://www.w3.org/1999/xlink">0.21</inf> Cu xmlns:xlink="http://www.w3.org/1999/xlink">0.08</inf> Ni xmlns:xlink="http://www.w3.org/1999/xlink">0.02</inf> Zr ) xmlns:xlink="http://www.w3.org/1999/xlink">7.6</inf> , were investigated with regard to their coercivity and magnetization process. It...

Fully dense magnets were prepared by hot pressing of the hydrogenation-decomposition-desorption-recombination (HDDR)-processed powders, and they had very fine microstructures. The typical magnetic properties HDDR pressed magnet with composition Nd13.0Fe62.9Co17.4B6.2Zr0.1Ga0.4 Br=1.26 T, HcJ=969 kA/m (BH)max=279 kJ/m3. surface morphology machined thin investigated. performance hardly depended on their thickness, that high coercivity Nd12.4Dy0.6Fe74.5Co5.8B6.2Zr0.1Ga0.4 is same because...

To decrease the hysteresis losses of soft magnetic composite (SMC) cores, it is effective that coercivity cores reduced by high temperature stress relieving annealing to green compacts. It reported about properties SMC, which MgO system evaporation insulation coating on surface iron powders had greater heat-resistance than conventional phosphate coating. We found can be obtained new SMC core with lower loss made from evaporated The them at 50 Hz for Bm = 1.5 T was 30% and almost same...

Rapidly quenched Pr–Co binary ribbons with various Pr contents in the range of 11.1∼18.1 at% were produced by single roller method and their magnetic properties investigated. It was found that 17.3 exhibit high coercivity value 1100 kA/m, which is two or three times higher than those sintered magnets system. These alloy consist only PrCo5 grains 0.3∼0.8 μm diameter. On contrary, other compositions, contain Pr2Co17 Pr5Co19 phase as a secondary phase, possess much lower values. This indicates...

Anisotropic fully dense Nd Fe-B magnets can be produced by compacting the HDDR-processed powder under an orienting magnetic field, and then hot pressing green compacts. In this study, we investigated field dependence of properties in pressed made from Nd12.7Dy0.3Fe64.3Co16.0B6.2Zr0.1Ga0.4 different stages HDDR process. It was found that semi-processed powder, which recombination reaction decomposed phases is not completed, more highly oriented applied fields less than 1190 kA/m comparison...

Soft magnetic composites (SMC) have attracted a growing interest since they the positive points in isotropic properties and high electric resistivity. They also advantage fabricating complex shape products easily. In this experiment, water atomized iron powder with phosphate insulator coating around its surface was mixed binder three kinds of SMC specimens were prepared. The first one is prepared without (Sample A), second by using silicon resin as C), third thermosetting polyimide D)....

By rapid quenching techiques directly from the liquid, Sm-Co binary ribbons were produced over range 20∼39wt% Sm. The samples melted and quenched in Ar gas atomosphere order to avoid oxidation. continuous obtained 20 50 μm thickness, 1 3 mm width about m length. These flexible, it was possible wind around a rod 8 diameter. coercivities of as-quenched for Sm content > 34 wt% (the stoichiometric SmCo5) almost same as sintered SmCo5 magnets. In case < wt%, higher than those systems.