Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared...Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared by the conventional precipitation method. Among various procedures for ethanol induced method, it was found that incorporation of ethanol in the precipitation process was the better. After incorporation of ethanol, the crystal size of CuO decreased and the reduction of copper species became easier. The better activity of Cu-Fe-Zr catalysts prepared by ethanol induced procedures was probably caused by the higher dispersion of Cu species.展开更多
Increasing iron content has been witnessed an essential method to improve the remanence of 2:17-type Sm-Co-Fe-Cu-Zr magnets,however,the inferior squareness factor accompanied with the increased iron content turns into...Increasing iron content has been witnessed an essential method to improve the remanence of 2:17-type Sm-Co-Fe-Cu-Zr magnets,however,the inferior squareness factor accompanied with the increased iron content turns into a neck sticking problem.In this work,the grain boundary optimization induced substantial squareness enhancement from 63.4%to 91.4%,and consequently an excellent maximum energy product of 32.63 MGOe have been achieved in iron-rich Sm-Co-Fe-Cu-Zr magnets via tuning solution process.It is clearly revealed that the grain boundary(GB)phases as well as the micro-twins’density in grain interiors can be controlled and interprets the enhancement mechanism of squareness.展开更多
Behavior of the coercivity of the high-temperature Sm(Co0.88-xFexCu0.09Zr0.03)7 magnets depending on the temperature and time of annealing with the temperature decreasing stepwise from 700 to 400℃ was investigated.It...Behavior of the coercivity of the high-temperature Sm(Co0.88-xFexCu0.09Zr0.03)7 magnets depending on the temperature and time of annealing with the temperature decreasing stepwise from 700 to 400℃ was investigated.It is shown that the growth rate of coercivity abruptly increases at the initial stage of annealing in the vicinity of the Curie temperature of the SmCo5 phase.The origin of the effect is the counter diffusion of Cu and Co atoms through dislocation tubes,which form because of enhanced stresses and a partial breakage of coherent coupling at the interface of the Sm2 Co17 and SmCo5 phases.Diffusive enrichment of the SmCo5 phase in Cu close to the interface with Sm2 Co17 leads to relaxation of stresses and increases in the gradient of the magnetic domain-wall energy and coercivity.展开更多
采用粉末冶金法制备烧结Sm(Co_(0.72)Fe_(0.15)Cu_(0.1)Zr_(0.03))_(7.5)永磁体,研究球磨时间对磁粉粒度、成分以及磁体磁性能的影响,并借助扫描电镜分析永磁体的显微组织结构,利用X射线电子能谱对永磁体进行成分分析。结果表明,球磨时...采用粉末冶金法制备烧结Sm(Co_(0.72)Fe_(0.15)Cu_(0.1)Zr_(0.03))_(7.5)永磁体,研究球磨时间对磁粉粒度、成分以及磁体磁性能的影响,并借助扫描电镜分析永磁体的显微组织结构,利用X射线电子能谱对永磁体进行成分分析。结果表明,球磨时间对磁粉平均粒度、粒度分布、永磁体磁性能、局部成分以及显微结构都有较大影响。Sm(Co_(0.72)Fe_(0.15)Cu_(0.1)Zr_(0.03))_(7.5)合金磁粉的最佳球磨时间是30 min,磁粉平均粒度大约为5.44μm,磁体孔隙较少,致密度较高,烧结时析出Sm_2O_3晶粒较少,在一定烧结和时效工艺下,制备的永磁体的综合磁性能最优:剩磁B_r=1.08 T(10.8 k Gs),感应矫顽力H_(cb)=795.4 k A/m(10.0 k Oe),内禀矫顽力H_(cj)=1901.6 k A/m(23.9 k Oe),最大磁能积(BH)max=217.8 k J/m^3(27.4 MGs Oe)。展开更多
基金Natural Science Foundation of State Key Laboratory of Coal Conversion(No09-610)
文摘Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared by the conventional precipitation method. Among various procedures for ethanol induced method, it was found that incorporation of ethanol in the precipitation process was the better. After incorporation of ethanol, the crystal size of CuO decreased and the reduction of copper species became easier. The better activity of Cu-Fe-Zr catalysts prepared by ethanol induced procedures was probably caused by the higher dispersion of Cu species.
基金financially supported by the National Key R&D Program of China(No.2018YFB2003901)NSFC-BRICS(No.51761145026)NSFC(Nos.91960101 and 51520105002)。
文摘Increasing iron content has been witnessed an essential method to improve the remanence of 2:17-type Sm-Co-Fe-Cu-Zr magnets,however,the inferior squareness factor accompanied with the increased iron content turns into a neck sticking problem.In this work,the grain boundary optimization induced substantial squareness enhancement from 63.4%to 91.4%,and consequently an excellent maximum energy product of 32.63 MGOe have been achieved in iron-rich Sm-Co-Fe-Cu-Zr magnets via tuning solution process.It is clearly revealed that the grain boundary(GB)phases as well as the micro-twins’density in grain interiors can be controlled and interprets the enhancement mechanism of squareness.
基金Project supported by BRICSSTI Framework Program for Basic Research(RFBR-BRICS)(17-52-80072)DST-BRICS,and the State Assignment of Ministry of Science and Education of Russia(topic “Magnet)(AAAA-A18-118020290129-5)
文摘Behavior of the coercivity of the high-temperature Sm(Co0.88-xFexCu0.09Zr0.03)7 magnets depending on the temperature and time of annealing with the temperature decreasing stepwise from 700 to 400℃ was investigated.It is shown that the growth rate of coercivity abruptly increases at the initial stage of annealing in the vicinity of the Curie temperature of the SmCo5 phase.The origin of the effect is the counter diffusion of Cu and Co atoms through dislocation tubes,which form because of enhanced stresses and a partial breakage of coherent coupling at the interface of the Sm2 Co17 and SmCo5 phases.Diffusive enrichment of the SmCo5 phase in Cu close to the interface with Sm2 Co17 leads to relaxation of stresses and increases in the gradient of the magnetic domain-wall energy and coercivity.
文摘采用粉末冶金法制备烧结Sm(Co_(0.72)Fe_(0.15)Cu_(0.1)Zr_(0.03))_(7.5)永磁体,研究球磨时间对磁粉粒度、成分以及磁体磁性能的影响,并借助扫描电镜分析永磁体的显微组织结构,利用X射线电子能谱对永磁体进行成分分析。结果表明,球磨时间对磁粉平均粒度、粒度分布、永磁体磁性能、局部成分以及显微结构都有较大影响。Sm(Co_(0.72)Fe_(0.15)Cu_(0.1)Zr_(0.03))_(7.5)合金磁粉的最佳球磨时间是30 min,磁粉平均粒度大约为5.44μm,磁体孔隙较少,致密度较高,烧结时析出Sm_2O_3晶粒较少,在一定烧结和时效工艺下,制备的永磁体的综合磁性能最优:剩磁B_r=1.08 T(10.8 k Gs),感应矫顽力H_(cb)=795.4 k A/m(10.0 k Oe),内禀矫顽力H_(cj)=1901.6 k A/m(23.9 k Oe),最大磁能积(BH)max=217.8 k J/m^3(27.4 MGs Oe)。
