Thermodynamic Calculations of the Rare Earth Permanent Magnets: Fe-RE Binary Systems

As the key sub-binary systems in the rare-earth (RE) permanent magnetic materials with excellent magnetic properties (e.g. Nd-Fe-B, Sm-Fe-N magnets), the Fe-RE binary systems were investigated widely due to the industrial applications of permanent magnets. In this work, the experimental data of phase equilibria and thermodynamic properties of the Fe-RE binary systems (RE=La, Ce, Pr, Nd) in the published literature are reviewed firstly. Based on available phase equilibria data and thermodynamic data, the Fe-RE binary systems are assessed thermodynamically using the CALPHAD method. As a result, further experimental information and thermodynamic calculations will be both required in order to develop thermodynamic database of the RE-Fe-B ternary systems, which is very useful to study the relations between alloy composition, microstructure and magnetic properties of novel Nd-Fe-B-based permanent magnets.

Download Full-text

Thermodynamic Calculation of Phase Equilibria in the Mn-RE (RE=Nd, Gd, Dy) Binary Systems

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.1036 ◽

2017 ◽

Vol 898 ◽

pp. 1036-1041

Author(s):

M.H. Rong ◽

S.D. Lin ◽

Jiang Wang ◽

H.Y. Zhou ◽

G.H. Rao

Keyword(s):

Magnetic Properties ◽

Thermodynamic Properties ◽

Phase Equilibria ◽

Thermodynamic Calculation ◽

Binary Systems ◽

Ternary Systems ◽

Experimental Information ◽

Calphad Method ◽

Self Consistent ◽

Ternary Intermetallic Compounds

Ternary intermetallic compounds with rare earth elements and transition metals in the RE-Mn-X (X=Si, Ge, Sn etc.) ternary systems show interesting magnetic properties. As key sub-binary systems of the RE-Mn-X (X=Si, Ge, Sn etc.) ternary systems, the information of phase equilibria and thermodynamic properties of the Mn-RE (RE=Nd, Gd, Dy) binary systems are indispensable to explore the RE-Mn-X (X=Si, Ge, Sn etc.) alloys with better magnetic properties. In this work, the experimental data of phase equilibria and thermodynamic properties of the Mn-RE (RE=Nd, Gd, Dy) binary systems in the published literature were reviewed. Based on the available experimental information, thermodynamic calculation of phase equilibria of the Mn-RE (RE=Nd, Gd, Dy) binary systems was performed using the CALPHAD method. As a result, further experimental investigation and thermodynamic optimization would be still necessary in order to develop the self-consistent and compatible thermodynamic database of the RE-Mn-based alloy systems.

Download Full-text

Thermodynamic Calculation of the Heavy Rare Earth Permanent Magnets: Fe-RE (RE=Gd, Tb, Dy, Lu) Binary Systems

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1142.62 ◽

2017 ◽

Vol 1142 ◽

pp. 62-68

Author(s):

Xiao Long Chen ◽

Jiang Wang ◽

Tai Li Chen ◽

Mao Hua Rong ◽

Guang Hui Rao ◽

...

Keyword(s):

Experimental Data ◽

Magnetic Properties ◽

Phase Equilibria ◽

Binary Systems ◽

Permanent Magnets ◽

Ternary Systems ◽

Calphad Method ◽

Experimental Investigations ◽

Heavy Rare Earth ◽

Microstructure And Magnetic Properties

The Fe-RE (RE=Gd, Tb, Dy, Lu) binary systems with the experimental data of phase equilibria and thermodynamic properties in the published literature were reviewed firstly. Based on available phase equilibria data and thermodynamic data, the Fe-RE (RE=Gd, Tb, Dy, Lu) binary systems were assessed thermodynamically using the CALPHAD method. As a result, further experimental investigations and thermodynamic calculations would be both required in order to develop thermodynamic database of the RE-Fe-B ternary systems, which is very useful to study the relations between alloy compositions, microstructure and magnetic properties of novel Nd-Fe-B-based permanent magnets.

Download Full-text

Microstructure and Magnetic Properties of RE2.28Fe13.58B1.14 Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.848.709 ◽

2016 ◽

Vol 848 ◽

pp. 709-714 ◽

Cited By ~ 3

Author(s):

Gang Fu ◽

Jiang Wang ◽

Mao Hua Rong ◽

Guang Hui Rao ◽

Huai Ying Zhou

Keyword(s):

Crystal Structure ◽

Magnetic Properties ◽

Rare Earth ◽

Single Phase ◽

Permanent Magnets ◽

Industrial Applications ◽

Arc Melting ◽

Light Rare Earth Elements ◽

Curie Temperatures ◽

Microstructure And Magnetic Properties

The rare-earth (RE) permanent magnets based on Nd2Fe14B with excellent magnetic properties have been widely used in industrial applications. In this work, the crystal structure, microstructure and magnetic properties of Nd2.28Fe13.58B1.14, Ce2.28Fe13.58B1.14 and Pr2.28Fe13.58B1.14 alloys prepared by arc-melting were investigated. The results show that all alloys are single phase with tetragonal Nd2Fe14B-type (space group P42/mnm). The Curie temperatures (Tc) of RE2.28Fe13.58B1.14 (RE=Nd, Ce, Pr) alloys are 583 K, 423 K and 557 K, respectively. On the other hand, the coercivities of Nd2.28Fe13.58B1.14 and Pr2.28Fe13.58B1.14 alloys are about 1.05 T and 1.23 T, respectively, while that of Ce2.28Fe13.58B1.14 alloy is only about 0.25 T due to the poor squareness of hysteresis loop. Meanwhile, the saturation magnetizations of Nd2.28Fe13.58B1.14 and Pr2.28Fe13.58B1.14 alloys are about 135 emu/g and 113 emu/g, respectively, while that of Ce2.28Fe13.58B1.14 alloy is about 97 emu/g. It was indicated that the Curie temperatures and magnetic properties of RE2.28Fe13.58B1.14 alloys with the same crystal structure are dependent on light rare earth elements.

Download Full-text

Thermodynamic Calculation of the Rare Earth Permanent Magnets: Fe-RE (RE=Ho, Er, Tm, Sm) Binary Systems

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.1042 ◽

2017 ◽

Vol 898 ◽

pp. 1042-1047

Author(s):

M.H. Rong ◽

X.L. Chen ◽

Jiang Wang ◽

S.D. Lin ◽

G.H. Rao ◽

...

Keyword(s):

Experimental Data ◽

Phase Diagram ◽

Thermodynamic Properties ◽

Thermodynamic Calculation ◽

Binary Systems ◽

Permanent Magnets ◽

Ternary Systems ◽

Calculated Phase Diagram ◽

Experimental Information ◽

Microstructure And Magnetic Properties

The experimental data of phase equilibria and thermodynamic properties of the Fe-RE (RE=Ho, Er, Tm, Sm) binary systems were reviewed. The previous thermodynamic calculation of the Fe-RE (RE=Ho, Er, Tm, Sm) binary systems were discussed based on the comparison of the calculated phase diagram and thermodynamic properties with the experimental data. The compared results show that more experimental information of phase diagram and thermodynamic properties in the Fe-RE (RE=Ho, Er, Tm, Sm) binary systems should be determined and then thermodynamic re-calculation of these binary systems would be performed to develop compatible and available thermodynamic database of the RE-Fe-B ternary systems. It is indispensable to study the relations between alloy compositions, microstructure and magnetic properties of novel Nd-Fe-B-based permanent magnets.

Download Full-text