The first one-step synthesis of dumbbell-like gold-iron oxide nanoparticles has been reported here. Surface functionalization with a biocompatible chitosan matrix allowed us to obtain a novel ...targetable diagnostic and therapeutic tool.
The first one-step synthesis of dumbbell-like gold-iron oxide nanoparticles has been reported here. Surface functionalization with a biocompatible chitosan matrix allowed us to obtain a novel targetable diagnostic and therapeutic tool.
Near-equiatomic Fe-Pd-based nanotubes with diameters of 200 nm and lengths of 1 km were directly electrodeposited from a single electrolyte into polycarbonate templates. The as-deposited Fe sub(50)Pd ...sub(50) nanotubes were then characterized compositionally, structurally and magnetically. The as-deposited Fe sub(50)Pd sub(50) tubes had an fcc crystal structure and were magnetically soft (H sub()Casymptotic to 10 kA/m), with the easy axis of the magnetization being parallel to the axes of the tubes. Angular-dependence measurements of the coercivity, where the hysteresis loops were measured as a function of the angle (theta) of the applied demagnetizing field, revealed a combination of magnetization reversal mechanisms, consisting of the curling mechanism, which dominates at low angles, with a transition to coherent rotation at angles >=70. The development of the coercivity with annealing temperature due to the L1 sub(0) ordering was also investigated. For this purpose the as-deposited nanotubes were annealed at temperatures from 400 C to 650 C for 1 h in Ar + 7% H sub(2) and the phase formation, the microstructure and the magnetic properties were analyzed. A maximum in the coercivity of 135 kA/m was achieved upon annealing at 550 C.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Spark plasma sintering (SPS) technique is applied in combination with hydrogen decrepitation process for the recycling of SmCo5 magnets. The SmCo5 magnets for recycling were first decrepitated by ...hydrogen gas of a pressure of 4 bar for 3 hours to produce decrepitated powder. This powder was then used to prepare isotropic sintered magnets using the SPS technique, by sintering at 800-1000 oC for 1 minute. Full densification of the SPS-ed magnets was possible at a temperature of 1000 oC. The sample sintered at 900 oC showed the best internal coercivity (jHc) of higher than 1500 kA/m with high remanence (Br) value of 0.47 T and energy product (BH(max)) of 43.4 kJ/m3. The properties of the SPS-ed sample sintered at 900 oC were compared with conventionally sintered (CVS-ed) sample prepared by using fresh SmCo5 powder. The results showed the improvement of the magnetic properties of the SPS-ed sample in comparison to the CVS-ed sample at room temperature, and the possibility to use the SPS-ed sample at high temperature of 180 oC, where the sample showed good magnetic properties of jHc of 1502 kA/m, Br of 0.44 T and BH(max) of 36.4 kJ/m3. The microstructure and X-ray diffraction patterns of the SPS-ed and the CVS-ed samples were studied; where the samples showed to basically consist of SmCo5 matrix phase with Sm2Co7 and Sm-oxides.
Understanding the interactions with nitrogen that happen during the processing of Sm-Fe-material is essential if we want to achieve the best magnetic properties. The magnetic behavior of Sm/sub ...13.7/Fe/sub 86.3/ and Sm/sub 13.8/Fe/sub 82.2/Ta/sub 4.0/ materials during nitriding processes was investigated using a specially designed vibrating-sample magnetometer (VSM) modified with a high-temperature (up to 1000/spl deg/C) vacuum-gas system. The nitriding process for the samples was performed at a heating rate of 5/spl deg/C/min to 500/spl deg/C and 1 bar. If the sample was previously hydrogenation-disproportionation-desorption-recombination (HDDR)-ed, the nitrogen uptake goes very smoothly; on the other hand, if the samples were not HDDR processed, the nitrogen reaction also consisted of the decomposition of SmFe/sub 2/ and SmFe/sub 3/ phases. In order to achieve good coercivities a combination of milling and the HDDR process is necessary.
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