Isothermal Sections of 1∶ 2, 1∶3 and 2∶ 17-type Compounds at 773 K in the Sm-Nd-Fe-Co Quaternary System

摘要

The isothermal sections of 1:2, 1:3 and 2:17-type compounds at 773 K in the Sm-Nd-Fe-Co quaternary system were determined by using optical microscopy, X-ray diffraction analysis, electron probe microanalysis. The NdCo2-SmCo2-SmFe2-NdFe2 section consists of 1 single-phase region: (Sm,Nd)(Fe,Co)2; 2 two-phase regions: (Sm,Nd)(Fe,Co)2+ (Sm,Nd)(Fe,Co)3, α(Nd,Sm)+(Sm,Nd)5(Fe,Co)17; 1 three-phase region: (Sm,Nd)(Fe,Co)2+ α(Nd,Sm)+(Sm,Nd)5(Fe,Co)17. The NdCo3-SmCo3-SmFe3-NdFe3 section consists of 1 single-phase region: (Sm,Nd)(Fe,Co)3; 2 two-phase regions: (Sm,Nd)(Fe,Co)3+ (Sm,Nd)2(Fe,Co)17, α(Nd,Sm)+(Sm,Nd)5(Fe,Co)17; 1 three-phase region: (Sm,Nd)2(Fe,Co)17+α(Nd,Sm)+(Sm,Nd)5(Fe,Co)17. There is a single-phase region: (Sm,Nd)2(Fe,Co)17 in the Nd2Co17-Sm2Co17-Sm2Fe17-Nd2Fe17 section. It has been found that the range of the single-phase region increases from the 1:2-type compound section to the 2:17-type compound section and the stability of the compounds does in the same way.