周谦莉
,
杜挺
金属学报
利用下列组装的固体电解质定氧电池Mo/Cr,Cr_2O_3//ZrO_2(MgO)//[O],Ce_2O_2S/Mo+ZrO_2金属陶瓷,Mo.在1600℃温度下对含微量C的Fe-Nb-Ce溶液进行热力学性质的研究。实验测得1600℃时Fe液中反应Ce_2O_2S=2[Ce]+2[O]+[S]的平衡常数和Ce_2O_2S的标准生成自由能分别为K=4.395×10~(-15),ΔG°_(Ce_2O_2S)=-514.786kJ·mol~(-1);Ce与Nb的活度相互作用系数为e_(Nb)~(Ce)=-2.306,e_(Ce)~(Nb)=-3.481。 随着Nb含量的增加,在微量碳含量的条件下,产物中存在NbC化合物,本文对NbC的生成问题进行了探讨,并得到1600℃时,Fe液中NbC的标准生成自由能为ΔG°_(NbC)=-87.111kJ·mol~(-1)。
关键词:
Fe-Nb-Ce溶液
,
thermodynamic properties
,
oxygen
,
sulphur
,
carbon
QIN Ziqiang YU Zongsen University of Science and Technology Beijing
,
Beijing
,
China QIN Ziqiang Department of Metal Physics
,
University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The segregation of sulphur at iron/graphite interfaces in both grey and nodular iron was in- vestigated with AES.Sulphur was found to nonequilibratorily segregate at the interfaces in grey iron,but not in nodular iron.Such different behaviors of segregation,which will exagger- ate the difference of grey and nodular iron in sulphur content at iron/graphite interfaces, might be derived from the difference of solidification process between the two irons.
关键词:
cast iron
,
null
,
null
,
null
ZHOU Qianli DU Ting Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China Senior engineer
,
Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China
金属学报(英文版)
The solid oxide electrolyte galvanic cell represented by Mo/Cr,Cr_2O_3//ZrO_2(MgO)//[O], Ce_2O_2S/Mo+ZrO_2 ceramic-metal,Mo have been used to study the thermodynamic proper- ties of Fe-Nb-Ce solution containing trace carbon at 1600℃.The equilibrium constant for the reaction Ce_2O_2S=2[Ce]+2[O]+[S] and the standard free energy of formation of Ce_2O_2S have been determined in liquid iron at 1600℃ as K=4.395×10~(-15).ΔG_(Ce_2)O_2S=-514.786 kJ·mol~(-1).The interaction coefficients between cerium and niobium are found to he e_(Nd)~(Ce)=-2.306,e_(Nd)~(Ce)=-3.481. The equilibrium products began to contain the compound NbC with the increase of Nh concentration in the condition of trace carbon.The formation of NbC is discussed in this work.The standard free energy of formation of NbC in liquid iron at 1600℃ have been de- termined as ΔG_(NbC)=-87.111 kJ·mol~(-1).
关键词:
Fe-Nb-Ce liquid solution
,
null
,
null
,
null
,
null
C. M. Liu1)
,
K. Abiko2) and M. Tanino2) 1) Schoolof Materials and Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China 2) Institute for Materials Research
,
Tohoku University
,
Sendai980
,
Japan
金属学报(英文版)
Effectoftheintergranularsegregationof Sonthehot ductilityof high purityiron wasquan titativelyinvestigated using high purityiron specimenscontaining < 2 ,5,10 ,20 and 60massppm Sby scanning AES,tensiletests under high vacuum and SEMof the fracturedsurface. The main resultsareasfollows: high purityironcontaininglessthan 2 massppm Sexhibitsanexcellenthotductility,thatis,reductionofareatofracturelargerthan95 % ,at alltesttemperaturesbetween673 and 1173 K. Dissolved Sof5 massppm causesanevident hot ductility dropof high purityiron at873～973 K.Increasingthedissolved Scontentfur ther decreases hot ductility and widensthetemperaturerange ofembrittlement. Theembrit tledspecimensfailinintergranular mode. Theamountoftheequilibrium intergranularseg regation of Sincreases withincreasingtheconcentration of dissolved Sand with decreasingthe annealingtemperature. Ssegregates much moreon cavitysurfacesthan atgrain boundaries.
关键词:
high purityiron
,
null
,
null
,
null
,
null
,
null
