The iso-activity of[Ce]of samples reached in multiple-hole-graphite crucibles by controlling the oxygen potential through the reaction 2[Ce]+3CO=Ce_(2)O_(3)+3C.Combining conjugate gradient method of solving ill-condit...The iso-activity of[Ce]of samples reached in multiple-hole-graphite crucibles by controlling the oxygen potential through the reaction 2[Ce]+3CO=Ce_(2)O_(3)+3C.Combining conjugate gradient method of solving ill-conditioned equations,the activity interaction coeffients between Ce and Al.Si,Ti and Fe alloying elements were determined.The equilibrium constant of the reaction 2[Ce]+3[O]=Ce_(2)O_(3)and the standard free energy of formation of Ce203 in liquid Cu were obtained at 1.200 C.展开更多
In this paper,dependence of magnetic properties on microstructure and composition of Ce-Fe-B sintered magnets with Cu-doped Ce-rich alloy addition was investigated.It shows that the maximum energy product(BH)(max)and ...In this paper,dependence of magnetic properties on microstructure and composition of Ce-Fe-B sintered magnets with Cu-doped Ce-rich alloy addition was investigated.It shows that the maximum energy product(BH)(max)and coercivity H(cj)of Ce-Fe-B sintered magnet are improved from 6.76 to 9.13 MGOe by 35.1%,and from 1.44 to 1.67 kOe by 16.0%,respectively,via adding 5 wt%liquid phase alloy of Ce(35.58)Fe(57.47)Cu6 B(0.95)(at%).Compared with the magnet without Cerich alloy addition,the volume fraction of the grain-boundary phase with low melting point increases in the magnet with Ce-rich alloy additio n,which is be ne ficial to imp roving the microstructure and promoting the coercivity enhancement of the magnet.In the Ce-Fe-B magnet with Ce-rich alloy addition,Cu and Ce enrich in the grain boundaries of the magnet after annealing,therefore the as-annealed magnet has a higher coercivity than the as-sintered magnet.A distinct Fe-rich layer with the average thickness of 60 nm is found in the grain boundaries in the magnet without Ce-rich alloy addition,but it seems that Fe-rich phase disappears in the magnet with Ce-rich alloy addition.The present work suggests that the further improvement of coercivity in the Ce-Fe-B sintered magnets is expectable by designing the composition and structure of added liquid phase alloys.展开更多
The equilibrium product in Fe-Cu-Ce,Fe-P-Ce or Fe-Ti-Ce solution have ben Mentified to be Ce_2O_2S,but not the intermetallic compounds of Ce against Cu,P or Ti.The equilibrium eonstant of Ce_2O_2S=2[Ce]+2[O]+[S] and t...The equilibrium product in Fe-Cu-Ce,Fe-P-Ce or Fe-Ti-Ce solution have ben Mentified to be Ce_2O_2S,but not the intermetallic compounds of Ce against Cu,P or Ti.The equilibrium eonstant of Ce_2O_2S=2[Ce]+2[O]+[S] and the interaction coefficients between solutes in Fe-base solution have been determined as follows: K_(Ce_2O_2S)=2.57×10^(-5) e_(Ce)^(Cu)=-0.49;e_(Ce)~P=1.77;e_(Ce)^(Ti)=-3.62 e_(Cu)^(Ce)=-0.22;e_P^(Ce)=0.39;e_(Ti)^(Ce)=-1.23 ε_(Ce)^(Cu)=-128.0;ε_(Ce)~P=-224.1;ε_(Ce)^(Ti)=-710.0 Ce decreases the activities of Cu and Ti in Fe-base solution and increases their solubifities,as well as increases the activity of P and decreases its solubility.展开更多
文摘The iso-activity of[Ce]of samples reached in multiple-hole-graphite crucibles by controlling the oxygen potential through the reaction 2[Ce]+3CO=Ce_(2)O_(3)+3C.Combining conjugate gradient method of solving ill-conditioned equations,the activity interaction coeffients between Ce and Al.Si,Ti and Fe alloying elements were determined.The equilibrium constant of the reaction 2[Ce]+3[O]=Ce_(2)O_(3)and the standard free energy of formation of Ce203 in liquid Cu were obtained at 1.200 C.
基金Project supported by the National Natural Science Foundation of China(51590882)the Plan of National Key Research and Development of China(2016YFB0700903)
文摘In this paper,dependence of magnetic properties on microstructure and composition of Ce-Fe-B sintered magnets with Cu-doped Ce-rich alloy addition was investigated.It shows that the maximum energy product(BH)(max)and coercivity H(cj)of Ce-Fe-B sintered magnet are improved from 6.76 to 9.13 MGOe by 35.1%,and from 1.44 to 1.67 kOe by 16.0%,respectively,via adding 5 wt%liquid phase alloy of Ce(35.58)Fe(57.47)Cu6 B(0.95)(at%).Compared with the magnet without Cerich alloy addition,the volume fraction of the grain-boundary phase with low melting point increases in the magnet with Ce-rich alloy additio n,which is be ne ficial to imp roving the microstructure and promoting the coercivity enhancement of the magnet.In the Ce-Fe-B magnet with Ce-rich alloy addition,Cu and Ce enrich in the grain boundaries of the magnet after annealing,therefore the as-annealed magnet has a higher coercivity than the as-sintered magnet.A distinct Fe-rich layer with the average thickness of 60 nm is found in the grain boundaries in the magnet without Ce-rich alloy addition,but it seems that Fe-rich phase disappears in the magnet with Ce-rich alloy addition.The present work suggests that the further improvement of coercivity in the Ce-Fe-B sintered magnets is expectable by designing the composition and structure of added liquid phase alloys.
文摘The equilibrium product in Fe-Cu-Ce,Fe-P-Ce or Fe-Ti-Ce solution have ben Mentified to be Ce_2O_2S,but not the intermetallic compounds of Ce against Cu,P or Ti.The equilibrium eonstant of Ce_2O_2S=2[Ce]+2[O]+[S] and the interaction coefficients between solutes in Fe-base solution have been determined as follows: K_(Ce_2O_2S)=2.57×10^(-5) e_(Ce)^(Cu)=-0.49;e_(Ce)~P=1.77;e_(Ce)^(Ti)=-3.62 e_(Cu)^(Ce)=-0.22;e_P^(Ce)=0.39;e_(Ti)^(Ce)=-1.23 ε_(Ce)^(Cu)=-128.0;ε_(Ce)~P=-224.1;ε_(Ce)^(Ti)=-710.0 Ce decreases the activities of Cu and Ti in Fe-base solution and increases their solubifities,as well as increases the activity of P and decreases its solubility.
