Based on the phase diagram of the Fe-Pr system available,the thermodynamic optimization and calcula- tion of the system have been carried out by the least square method.The lattice stabilities of Fe and Pr are describ...Based on the phase diagram of the Fe-Pr system available,the thermodynamic optimization and calcula- tion of the system have been carried out by the least square method.The lattice stabilities of Fe and Pr are described by the expression recommended by SGTE organization.The liquid phase is described by the subregular solution model.The intermetallic compounds,Fe_(17)Pr_2 and Fe_2Pr,are treated as stoichiometric compounds.The optimized parameters describing phases in the system are presented.The comparision be- tween the calculated and experimentally determined phase diagram shows that the agreement is generally very good except for the liquid+δ-Fe equilibrium.It is suggested to measure this part of phase diagram again.展开更多
Pr_(83)Cu_(17)(wt%) grain boundary reconstruction was applied to prepare sintered NdFeB magnets. The effects of addition amount and annealing on the bending strength were investigated. The results show that Pr_(83)Cu_...Pr_(83)Cu_(17)(wt%) grain boundary reconstruction was applied to prepare sintered NdFeB magnets. The effects of addition amount and annealing on the bending strength were investigated. The results show that Pr_(83)Cu_(17) can not only effectively enhance the bending strength, but also change the mechanical anisotropy in two directions parallel and perpendicular to c-axis. The bending strength perpendicular to c-axis reaches 404 MPa in 10 wt% addition magnet, higher than 348 MPa along parallel direction. This change is attributed to the preferred distribution of boundary phases, i.e., ductile(Nd,Pr)-Fe-Cu phase along perpendicular direction to c-axis and(Nd,Pr)-Fe phase along parallel direction. Moreover, the Cu migration during 480 ℃ annealing is found to be related to this boundary phase distribution.展开更多
Cyclic voltammetry and chronoamperometry were used to investigate theelectrochemical behavior of Pr^(3+) ions in a system of 0.01 mol centre dot dm^(-3) Pr(CH_3SO_3)_3 +0.01 mol centre dot dm^(-3) FeCl_2 + 3.0 mol cen...Cyclic voltammetry and chronoamperometry were used to investigate theelectrochemical behavior of Pr^(3+) ions in a system of 0.01 mol centre dot dm^(-3) Pr(CH_3SO_3)_3 +0.01 mol centre dot dm^(-3) FeCl_2 + 3.0 mol centre dot dm^(-3) urea + DMSO on a R electrode. Someelectrochemical parameters were measured. Potentiostatic depositions between -1.6 and -2.4 V wereapplied to deposit Pr-Fe films in urea-DMSO mixed solution. The Pr content in the alloy films was inthe range of 34.89 wt. percent to 37.15 wt. percent. The Pr-Fe alloy films are proven to beamorphous by XRD (X-ray diffraction).展开更多
文摘Based on the phase diagram of the Fe-Pr system available,the thermodynamic optimization and calcula- tion of the system have been carried out by the least square method.The lattice stabilities of Fe and Pr are described by the expression recommended by SGTE organization.The liquid phase is described by the subregular solution model.The intermetallic compounds,Fe_(17)Pr_2 and Fe_2Pr,are treated as stoichiometric compounds.The optimized parameters describing phases in the system are presented.The comparision be- tween the calculated and experimentally determined phase diagram shows that the agreement is generally very good except for the liquid+δ-Fe equilibrium.It is suggested to measure this part of phase diagram again.
基金National Natural Science Foundation of China(51361007)Guangxi Natural Science Foundation(2014GXNSFAA118317,2013GXNSFAA019295)+1 种基金Scientific Research Project of Guangxi Education Department(YB2014139)Guangxi Key Laboratory of Information Materials(131010-Z)
基金supported by National Natural Science Foundation of China(51401021)the State Key Laboratory Advanced Metals and Materials(20162-14)
文摘Pr_(83)Cu_(17)(wt%) grain boundary reconstruction was applied to prepare sintered NdFeB magnets. The effects of addition amount and annealing on the bending strength were investigated. The results show that Pr_(83)Cu_(17) can not only effectively enhance the bending strength, but also change the mechanical anisotropy in two directions parallel and perpendicular to c-axis. The bending strength perpendicular to c-axis reaches 404 MPa in 10 wt% addition magnet, higher than 348 MPa along parallel direction. This change is attributed to the preferred distribution of boundary phases, i.e., ductile(Nd,Pr)-Fe-Cu phase along perpendicular direction to c-axis and(Nd,Pr)-Fe phase along parallel direction. Moreover, the Cu migration during 480 ℃ annealing is found to be related to this boundary phase distribution.
文摘Cyclic voltammetry and chronoamperometry were used to investigate theelectrochemical behavior of Pr^(3+) ions in a system of 0.01 mol centre dot dm^(-3) Pr(CH_3SO_3)_3 +0.01 mol centre dot dm^(-3) FeCl_2 + 3.0 mol centre dot dm^(-3) urea + DMSO on a R electrode. Someelectrochemical parameters were measured. Potentiostatic depositions between -1.6 and -2.4 V wereapplied to deposit Pr-Fe films in urea-DMSO mixed solution. The Pr content in the alloy films was inthe range of 34.89 wt. percent to 37.15 wt. percent. The Pr-Fe alloy films are proven to beamorphous by XRD (X-ray diffraction).
