Thermodynamics and magnetism of selected complex intermetallic compounds and their hydrides
Many complex intermetallic compounds exhibit a large chemical affinity and solubility for hydrogen. Accompanying hydriding the physical properties (structural, thermodynamic, magnetic, etc.) of the compounds significantly differ from those of the parent intermetallics. In this study, the following systems were studied: ZrMn{sub 2}, ZrCrFe and ZrVCo; ZrMn{sub 2}T{sub 0.8} (T = Fe, Co, Ni and Cu); R{sub 2}Fe{sub 14}B (R = Gd, Tb, Dy, Ho and Er) and R{sub 2}Co{sub 14}B (R = La, Pr, Nd, Sm, Gd, Tb and Y). For the isoelectronic series of alloys all of the host alloys and hydrides crystallize in the C14 type structures. Pressure composition isotherms (PCIs) were determined. The standard thermodynamic quantities were derived from the measured PCIs and from calorimetric measurements. Magnetic properties were investigated for hyperstoichiometric systems and their hydrides. Hydrogenation is accompanied by a large expansion in unit-cell volume. Hydrogenation enhances magnetism in all cases. The systems exhibit susceptibility behavior. Unusual history-dependent magnetic behavior was observed for hydrides below 80 K. R{sub 2}Fe{sub 14}B systems were hydrogenated. The pressure-composition isotherms (PCIs) of hydrides showed only a solid solution behavior between room temperature and 300 C and at pressures down to 10{sup {minus}2} atm.
- Research Organization:
- Pittsburgh Univ., PA (USA)
- OSTI ID:
- 5180887
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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