Nanocomposite Sm2Co17/Co permanent magnets by mechanical alloying

Abstract

Mechanically alloyed magnets SmCox (x=6.0–11.0) have been prepared using starting materials of commercial SmCo5 and Co powders. X-ray diffraction data indicate that the equilibrium Sm2Co17 phase can be achieved in a nanocomposite Sm2Co17/Co system at x=8.5–11.0, while a Sm2Co17/SmCo5 structure occurs at x=6.0–8.0. The best magnetic properties obtained at x=10.0 are as follows: (BH)max=10.2 MGOe, Br=9.4 kG, Hc=4.0 kOe, and S=0.82. Wohlfarth’s remanence analysis indicates that the high remanence can be attributed to the intergranular interaction between neighboring cobalt and Sm2Co17 grains.

A Facile Synthesis of SmCo5 Magnets from Core/Shell Co/Sm2O3 Nanoparticles

“…Ball milling and melt spinning, the two standard physical methods used for the fabrication of nanostructured SmCo 5 magnets, provide only limited control of the sizes of the final magnetic grains. [15][16][17][18][19][20][21][22][23] Solution-phase chemical synthesis approaches have been applied to prepare monodisperse magnetic nanoparticles, and have recently been extended to the synthesis of SmCo 5 nanoparticles by coupling the polyol reduction of samarium acetylacetonate, Sm(acac) 3 , with the thermal decomposition of Co 2 (CO) 8 . [24][25][26][27] Although the molar ratio of Sm/Co in the cles.…”

Solar Thermoelectric Generator for Micropower Applications

“…The temperature of 900 K in Ref. 6 is not achievable primarily because the radiative loss (for e = 1) exceeds the incident solar flux and because the material ZT for Bi 2 Te 3 degrades at such high temperature.…”

“…A recently published model estimates a maximum system efficiency of 35% for a flat-plate (19 solar concentration) solar thermoelectric system. 6 Herein we show that the recently reported models are unphysicalspecifically they treat the hot-side heat transfer inconsistently, resulting in hot-side temperatures of 900 K without solar concentration. 6 In fact, for a Bi 2 Te 3 module with natural air convection, the heat flux at low solar concentration using flat-plate or box-type concentrators results in a relatively low hot-side temperature (<320 K).…”

Experimental Performance of a Solar Thermoelectric Cogenerator Comprising Thermoelectric Modules and Parabolic Trough Concentrator without Evacuated Tube

“…4 However, due to the low TE conversion efficiency of such systems, the STEPG concept went unnoticed for a long time until the recent revival after review of its advantages, which are exemplified as: small scale (compact system without a large heat transfer system), high output power density, low maintenance cost, long operating time, stable output, and utilization of a wide solar spectral range (300 nm to 2500 nm) through absorption by a solar plate. 5 Most recent studies on either TEPG or STEPG have paid more attention to optimization of the TE devices by selecting materials with high ZT values, 6 appropriate design of the TE structure, 7 thermodynamic analysis of the TEPG, 8,9 and construction of small TEPG devices. 9 Work on STEPG with single TE modules was reported in Refs.…”