Structure, phase transformation, and magnetic properties of R_(16)Fe_(76-x)Co_xC_8 (R ident to Nd, Dy; 0<=x<=76) alloys prepared by a remilling process

摘要

The effect of Co substitution on structure, phase transformation, and magnetic properties of R_(16)Fe_(76-x)Co_xC_8 (R ident to Nd, Dy; 0<=x<=76) alloys prepared by a remilling process has been studied systematically. The process of remilling and subsequent annealing is more beneficial for the formation of Nd_2(Fe,Co)_(14)C compound in Nd_(16)Fe_(76-x)Co_xC_8 alloys than in R_(16)Fe_(76-x)Co_xC_8 alloys. The R_2(Fe,Co)_(14)C phase is obtained for Nd_(16)Fe_(76-x)Co_xC_8 alloys with 0<=x<=20 and Dy_(16)Fe_(76-x)Co_xC_8 alloys with 0<=x<=25. Higher Co content results in the formation of Nd_2(Fe,Co)_(17)C_(delta)-type phase and Dy(Fe,Co)_7 phase for Nd_(16)Fe_(76-x)Co_xC_8 and R_(16)Fe_(76-x)Co_xC_8 alloys, respectively. The high coercivity, _iH_c=48.5 kOe, is achieved for Dy_(16)Fe_(51)Co_(25)C_8 alloy.