At different annealing temperatures, the saturation magnetostrictions and the correlation between the permeability μi and the temperature T （μi-T curves） of the Co66Fe4Mo2Si16B12 alloy were investigated using a sm...At different annealing temperatures, the saturation magnetostrictions and the correlation between the permeability μi and the temperature T （μi-T curves） of the Co66Fe4Mo2Si16B12 alloy were investigated using a small-angle magnetization tester and core tester. The experimental results showed that the μi-T curves had different shapes at different ranges of annealing temperature; the permeability μi of the alloy improved with the increase of the annealing temperatures below 460℃; when the alloy was annealed above 480℃, the poor magnetic properties were considered to be caused by larger saturation magnetostriction.展开更多
The bulk Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1, 3, 5, 7, 9） amorphous rods with diameters of 1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials....The bulk Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1, 3, 5, 7, 9） amorphous rods with diameters of 1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials. The amorphous and crystalline states, and thermal parameters, such as the glass transition temperature （Tg）, the initial crystallization temperature （Tx）, the supercooled liquid region （ΔTx=Tx-Tg）, the reduced glass transition temperature T<sup>rg （Tg/Tm, Tm: the onset temperature of melting of the alloy, and Tg/Tl, Tl: the finished temperature of melting of the alloy） were investigated by X-ray diffractometry （XRD） and differential scanning calorimetry （DSC） analysis. Glass forming ability of Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1,3,5,7,9） bulk metallic glasses has been studied. According to the results, the alloy （x=7） with the highest T<sup>rg （Tg/Tl=0.607, Tg/Tl=0.590） value, has the strongest glass forming ability among these alloys because its composition is near eutectic composition. The wide supercooled liquid region over 72 K indicates the high thermal stability for this alloy system. This bulk metallic glass exhibits quite high strength （Hv 1020）. The success of production of the Fe-based bulk metallic glass with industrial materials is of great significance for the future progress of basic research and practical application.展开更多
A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits ...A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits I4/m symmetry. The cation order η of the sample increases to 98.9（2）% from 94.2（3）%, which is prepared by the traditional sol-gel method. The initial magnetization isotherm of the sample is detected at 300 K. Unit-cell magnetization for the current sample is 1.332 #s at 300 K, and the one for the traditional sol-gel method sample is 0.946#9. Unit-cell magnetization is enhanced to 40.80% by the quench-treatment technique. Quench treatment is an effective method of enhancing the Fe/Mo order and magnetic properties of double perovskite SFMO.展开更多
Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have ...Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have been limited by insufficient durability in both alkaline and acidic environments.In particular,limited attention has been paid to stabilizing iron-based catalysts by introducing additional metal by the alloying effect.Herein,we report bimetallic Fe_(2)Mo nanoparticles on N-doped carbon(Fe_(2)Mo/NC)as an efficient and ultra-stable ORR electrocatalyst for the first time.The Fe_(2)Mo/NC catalyst shows high selectivity for a four-electron pathway of ORR and remarkable electrocatalytic activity with high kinetics current density and half-wave potential as well as low Tafel slope in both acidic and alkaline medias.It demonstrates excellent long-term durability with no activity loss even after 10,000 potential cycles.Density functional theory(DFT)calculations have confirmed the modulated electronic structure of formed Fe_(2)Mo,which supports the electron-rich structure for the ORR process.Meanwhile,the mutual protection between Fe and Mo sites guarantees efficient electron transfer and long-term stability,especially under the alkaline environment.This work has supplied an effective strategy to solve the dilemma between high electroactivity and long-term durability for the Fe-based electrocatalysts,which opens a new direction of developing novel electrocatalyst systems for future research.展开更多
The Fe48Cr15Mo14Er2C15B6amorphous steel can hardly be used as an engineering material because of its ex- treme brittleness and very low iron content. By changing the composition of the nonmagnetic amorphous steel, and...The Fe48Cr15Mo14Er2C15B6amorphous steel can hardly be used as an engineering material because of its ex- treme brittleness and very low iron content. By changing the composition of the nonmagnetic amorphous steel, and using the relation between the reduced glass transition tempera- ture Trg and the glass forming ability, a new amorphous Fe56Mn5Cr7Mo12Er2C12B6 alloy with good glass forming abil- ity and high iron content was obtained. The diameter of the as-cast sample rod reached 8 mm. This new amorphous steel has lower manufacturing cost due to its high iron content, and thus it can have wider applications.展开更多
文摘At different annealing temperatures, the saturation magnetostrictions and the correlation between the permeability μi and the temperature T （μi-T curves） of the Co66Fe4Mo2Si16B12 alloy were investigated using a small-angle magnetization tester and core tester. The experimental results showed that the μi-T curves had different shapes at different ranges of annealing temperature; the permeability μi of the alloy improved with the increase of the annealing temperatures below 460℃; when the alloy was annealed above 480℃, the poor magnetic properties were considered to be caused by larger saturation magnetostriction.
文摘The bulk Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1, 3, 5, 7, 9） amorphous rods with diameters of 1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials. The amorphous and crystalline states, and thermal parameters, such as the glass transition temperature （Tg）, the initial crystallization temperature （Tx）, the supercooled liquid region （ΔTx=Tx-Tg）, the reduced glass transition temperature T<sup>rg （Tg/Tm, Tm: the onset temperature of melting of the alloy, and Tg/Tl, Tl: the finished temperature of melting of the alloy） were investigated by X-ray diffractometry （XRD） and differential scanning calorimetry （DSC） analysis. Glass forming ability of Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1,3,5,7,9） bulk metallic glasses has been studied. According to the results, the alloy （x=7） with the highest T<sup>rg （Tg/Tl=0.607, Tg/Tl=0.590） value, has the strongest glass forming ability among these alloys because its composition is near eutectic composition. The wide supercooled liquid region over 72 K indicates the high thermal stability for this alloy system. This bulk metallic glass exhibits quite high strength （Hv 1020）. The success of production of the Fe-based bulk metallic glass with industrial materials is of great significance for the future progress of basic research and practical application.
基金Supported by the National Natural Science Foundation of China under Grant No U1304110the Doctoral Science Foundation of Henan Normal University under Grant No 01026500109
文摘A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits I4/m symmetry. The cation order η of the sample increases to 98.9（2）% from 94.2（3）%, which is prepared by the traditional sol-gel method. The initial magnetization isotherm of the sample is detected at 300 K. Unit-cell magnetization for the current sample is 1.332 #s at 300 K, and the one for the traditional sol-gel method sample is 0.946#9. Unit-cell magnetization is enhanced to 40.80% by the quench-treatment technique. Quench treatment is an effective method of enhancing the Fe/Mo order and magnetic properties of double perovskite SFMO.
基金supported by the National Key R&D Program of China(No.2021YFA1501101)the National Nature Science Foundation of China(Nos.21862011,21771156,and 51864024)+4 种基金Yunnan province(No.2019FI003)the Shenzhen Knowledge Innovation Program(Basic Research,No.JCYJ20190808181205752)the Research Grants Council(RGC)of the Hong Kong Special Administrative Region,China(Project No.CityU 11206520)the National Natural Science Foundation of China/RGC Joint Research Scheme(No.N_PolyU502/21)the funding for Projects of Strategic Importance of The Hong Kong Polytechnic University(Project Code:1-ZE2V).
文摘Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have been limited by insufficient durability in both alkaline and acidic environments.In particular,limited attention has been paid to stabilizing iron-based catalysts by introducing additional metal by the alloying effect.Herein,we report bimetallic Fe_(2)Mo nanoparticles on N-doped carbon(Fe_(2)Mo/NC)as an efficient and ultra-stable ORR electrocatalyst for the first time.The Fe_(2)Mo/NC catalyst shows high selectivity for a four-electron pathway of ORR and remarkable electrocatalytic activity with high kinetics current density and half-wave potential as well as low Tafel slope in both acidic and alkaline medias.It demonstrates excellent long-term durability with no activity loss even after 10,000 potential cycles.Density functional theory(DFT)calculations have confirmed the modulated electronic structure of formed Fe_(2)Mo,which supports the electron-rich structure for the ORR process.Meanwhile,the mutual protection between Fe and Mo sites guarantees efficient electron transfer and long-term stability,especially under the alkaline environment.This work has supplied an effective strategy to solve the dilemma between high electroactivity and long-term durability for the Fe-based electrocatalysts,which opens a new direction of developing novel electrocatalyst systems for future research.
基金This work was supported by the National Natural Science Foundation of China(Grans No.50371098 and 50321101)the Key Project of the Beiing Science and Technology Program(Contract No.H02040030320).
文摘The Fe48Cr15Mo14Er2C15B6amorphous steel can hardly be used as an engineering material because of its ex- treme brittleness and very low iron content. By changing the composition of the nonmagnetic amorphous steel, and using the relation between the reduced glass transition tempera- ture Trg and the glass forming ability, a new amorphous Fe56Mn5Cr7Mo12Er2C12B6 alloy with good glass forming abil- ity and high iron content was obtained. The diameter of the as-cast sample rod reached 8 mm. This new amorphous steel has lower manufacturing cost due to its high iron content, and thus it can have wider applications.
