The Fe-Pt based intermetallic compounds exhibit good chemical stability and unique magnetic proper-ties,where Ni is an important additional element to optimize the magnetic properties or obtain the outstanding catalyt...The Fe-Pt based intermetallic compounds exhibit good chemical stability and unique magnetic proper-ties,where Ni is an important additional element to optimize the magnetic properties or obtain the outstanding catalytic performances of the Fe-Pt based alloys.Knowledge of how Ni addition affects the order-disorder transitions of the Fe-Pt intermetallics is thus necessary;however,the related information is limited.Therefore,in this work,the phase diagrams of the Fe-Ni-Pt system were experimentally in-vestigated,and as a result,the isothermal sections of the Fe-Ni-Pt system at 600 and 900℃,as well as the vertical sections of Fe_(80)Ni_(20)-Pt_(80)Ni_(20)and Fe_(50)Pt_(50)-Ni_(50)Pt_(50)were constructed.Based on these re-sults,the influences of Ni addition on the crystal stabilities and phase transformations of the ordered Fe-Pt intermetallics have been well described.The results show that the L1_(0)-FePt and L1_(0)-NiPt phases form a ternary continuous solid solution of L1_(0)-(Fe,Ni)Pt,whereas Ni can dissolve in the L1_(2)-Fe_(3)Pt and L1_(2)-FePt_(3)phases as high as 57.0 at.%and 26.0 at.%at 600℃,respectively.The selective occupancy of Ni atoms has been predicted,which should depend on the alloy composition.For both the L1_(0)-(Fe,Ni)Pt and L1_(2)-FePt_(3)phases,when Pt contents are less than their stoichiometric values,Ni atoms will preferentially occupy the Pt sublattice,forming as many nearest-neighbor Fe-Pt bonds as possible.All these results can correlate the alloy compositions,annealing temperatures and crystal structures to both magnetic and catalytic properties,thus providing a basis for optimizing the Fe-Ni-Pt alloys towards enhanced magnetic or catalytic performances.展开更多
基金supported by the Major Scientific and Technological Projects in Yunnan Province(No.202002AB080001-1)the National Natural Science Foundation of China(Nos.U1602275 and 51971059).Special thanks are due to the instrumen-tal data analysis from the Analytical and Testing Center,Northeast-ern University。
文摘The Fe-Pt based intermetallic compounds exhibit good chemical stability and unique magnetic proper-ties,where Ni is an important additional element to optimize the magnetic properties or obtain the outstanding catalytic performances of the Fe-Pt based alloys.Knowledge of how Ni addition affects the order-disorder transitions of the Fe-Pt intermetallics is thus necessary;however,the related information is limited.Therefore,in this work,the phase diagrams of the Fe-Ni-Pt system were experimentally in-vestigated,and as a result,the isothermal sections of the Fe-Ni-Pt system at 600 and 900℃,as well as the vertical sections of Fe_(80)Ni_(20)-Pt_(80)Ni_(20)and Fe_(50)Pt_(50)-Ni_(50)Pt_(50)were constructed.Based on these re-sults,the influences of Ni addition on the crystal stabilities and phase transformations of the ordered Fe-Pt intermetallics have been well described.The results show that the L1_(0)-FePt and L1_(0)-NiPt phases form a ternary continuous solid solution of L1_(0)-(Fe,Ni)Pt,whereas Ni can dissolve in the L1_(2)-Fe_(3)Pt and L1_(2)-FePt_(3)phases as high as 57.0 at.%and 26.0 at.%at 600℃,respectively.The selective occupancy of Ni atoms has been predicted,which should depend on the alloy composition.For both the L1_(0)-(Fe,Ni)Pt and L1_(2)-FePt_(3)phases,when Pt contents are less than their stoichiometric values,Ni atoms will preferentially occupy the Pt sublattice,forming as many nearest-neighbor Fe-Pt bonds as possible.All these results can correlate the alloy compositions,annealing temperatures and crystal structures to both magnetic and catalytic properties,thus providing a basis for optimizing the Fe-Ni-Pt alloys towards enhanced magnetic or catalytic performances.
