Stability of PrCo5+delta and Pr1-xHfxCo5+delta alloys with TbCu7-type structure at 900-1150 degrees C and their magnetic properties

作者：Gabay A M^*; Hadjipanayis G C

来源：Journal of Alloys and Compounds, 2011, 509(5): 2562-2566.

DOI：10.1016/j.jallcom.2010.11.090

• Permanent magnets
• Rare earth-cobalt magnets
• Phase equilibria
• TbCu7 structure

The TbCu7-type structure in bulk Pr-Hf-Co alloys was obtained by high-temperature homogenization of alloys adjacent to the PrCo5 composition. At 1150 degrees C, the homogeneity range of binary PrCo5+delta structure stretches to 84.5 at.% Co; addition of up to 1.5 at.% Hf extends this range to 85.3 at.% Co. The lattice constants, Curie temperature and room-temperature saturation magnetization of the PrCo5+delta phase approximately follow the Vegard's law as if this phase were transitional between the stoichiometric PrCo5 phase and the hypothetical disordered Pr2Co17 phase. Hafnium decreases the saturation magnetization of the Pr1-xHfCo5+delta phase, but has no significant effect on its Curie temperature. The highest saturation magnetization of 12.9 kG was observed in the off-stoichiometric binary alloy Pr84.5Co15.5. The solubility of Co in the PrCo5 structure was found to decrease with decreasing the homogenization temperature; only Pr1-xHfxCo5 alloys exhibited the single-phase structure after annealing at 900 degrees C.

• 出版日期2011-2-3