No abstract

Chemically ordered L10-type FeNi, also known as tetrataenite, is under investigation as a rare-earth-free advanced permanent magnet. Correlations between crystal structure, microstructure and magnetic properties of naturally occurring tetrataenite with a slightly Fe-rich composition (~ Fe55Ni44) obtained from the meteorite NWA 6259 are reported and augmented with computationally derived results. The tetrataenite microstructure exhibits three mutually orthogonal crystallographic variants of the L10 structure that reduce its remanence; nonetheless, even in its highly unoptimized state tetrataenite provides a room-temperature coercivity of 95.5 kA m(-1) (1200 Oe), a Curie temperature of at least 830 K and a largely temperature-independent anisotropy that preliminarily point to a theoretical magnetic energy product exceeding (BH)max = 335 kJ m(-3) (42 MG Oe) and approaching those found in today's best rare-earth-based magnets.

The mesoporous framework [Cu(3)(L)(H(2)O)(3)]·(DMF)(35)·(H(2)O)(35) (NOTT-119) shows on desolvation a BET surface area of 4118(200) m(2) g(-1), a pore volume of 2.35 cm(3) g(-1), a total H(2) uptake of 101 mg g(-1) at 60 bar, 77 K and a total CH(4) uptake of 327 mg g(-1) at 80 bar, 298 K.

The measurements and analysis of hydrogen adsorption isotherms on the metal-organic framework Zn 4 O(benzenedicarboxylate) 3 , IRMOF-1, at temperatures ranging from 50 to 100 K and pressures up to 40 bar are presented. The maximum excess adsorption amount measured on this material is about 9 wt % at 10 bar and 50 K. For the lowest temperatures, the measured excess adsorption isotherms exhibit a maxima and then decrease rapidly as function of pressure. The data collected in the decreasing region of the excess isotherms are used for the calculation of the adsorbed phase density and the absolute isotherms. Under these conditions, the adsorbed phase is found to behave like an incompressible fluid having a density comparable to that of hydrogen in its liquid state. The absolute isotherms, obtained by modeling the isotherms using a modified micropore filling model, can be up to 30% higher than the excess maxima depending on the equilibrium pressure and temperature. The adsorption enthalpy, expressed as function of fractional filling and temperature, lies within a typical physisorption range of 3-6 kJ/mol.