The iso-electric point of different rare earths （La, Ce, Y） doped anatase TiO2 was set out, and three organisms with different sur- face electrical properties （methylene blue trihydrate-positive electricity, methyl...The iso-electric point of different rare earths （La, Ce, Y） doped anatase TiO2 was set out, and three organisms with different sur- face electrical properties （methylene blue trihydrate-positive electricity, methyl orange-negative electricity, methyl red-neutral electricity） were selected as photodegradable models. The result showed that the photocatalytic activity of 0.5wt.%Y ions doped anatase TiO2 was better than those of the others. The relationship between Zeta （ξ） potential and the photocatalytic activity of different RE doped anatase TiO2 were also investigated. The Y-doped anatase TiO2 was found with the special two iso-electric points and three ξ potential values.展开更多
1.Export situation from January to June 20241.1 Overall export situation of rare earth products Export value of rare earth products showed a wholistic down trend affected by the continuousdecline in rare earth prices ...1.Export situation from January to June 20241.1 Overall export situation of rare earth products Export value of rare earth products showed a wholistic down trend affected by the continuousdecline in rare earth prices in the first half year,however,export volume increased.According to statistics from the General Administration of Customs,from January to June 2024,China's cumulative export of rare earth products was 29,095 tons,an increase of 11%year-on-year,with a cumulative export value of 256 million US dollars,a decrease of 43% year-on-year,Figure 1.展开更多
The overall rare earth market was relatively stagnant in the first half of 2024,with mainstream rare earth prices downward..On the supply side:The production quotas for mining and separation allocated for light rare e...The overall rare earth market was relatively stagnant in the first half of 2024,with mainstream rare earth prices downward..On the supply side:The production quotas for mining and separation allocated for light rare earths in the first half of 2024 was increased compared with that in the same period of 2023;Supply of raw materials was sufficient for separation enterprises;Recycling enterprises were operated under their capacity.展开更多
Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has ...Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.展开更多
The solid oxide fuel cell (SOFC) is a high-efficient and environmentally friendly power generation system.The rare earth oxide materials are used extensively in the manufacturing of SOFC components.In particular, the ...The solid oxide fuel cell (SOFC) is a high-efficient and environmentally friendly power generation system.The rare earth oxide materials are used extensively in the manufacturing of SOFC components.In particular, the CeO2doped with Gd2O3 or Sm2O3, lanthanide perovskite oxides are indispensable and key materials for developing the intermediate temperature SOFC.The research and development status of application of high purity rare earth oxides in SOFC was overviewed.The rare earth oxide-based and -doped materials were discussed for the SOFC components.Concerning the rare earth oxides applicable to SOFC, several topics were also pointed out for further researching and developing.展开更多
Interface modulation is an important pathway for highly efficient electromagnetic wave absorption.Herein,tailored interfaces between Fe_(3)O_(4)particles and the hexagonal-YFeO_(3)(h-YFeO_(3))framework were constructe...Interface modulation is an important pathway for highly efficient electromagnetic wave absorption.Herein,tailored interfaces between Fe_(3)O_(4)particles and the hexagonal-YFeO_(3)(h-YFeO_(3))framework were constructed via facile self-assembly.The resulting interfa-cial electron rearrangement at the heterojunction led to enhanced dielectric and magnetic loss synergy.Experimental results and density function theory(DFT)simulations demonstrate a transition in electrical properties from a half-metallic monophase to metallic Fe_(3)O_(4)/h-YFeO_(3)composites,emphasizing the advantages of the formed heterointerface.The transformation of electron behavior is also accompan-ied by a redistribution of electrons at the Fe_(3)O_(4)/h-YFeO_(3)heterojunction,leading to the accumulation of localized electrons around the Y-O-Fe band bridge,consequently enhancing the polarization.A minimum reflection loss of-34.0 dB can be achieved at 12.0 GHz and 2.0 mm thickness with an effective bandwidth of 3.3 GHz due to the abundant interfaces,enhanced polarization,and rational impedance.Thus,the synergistic effects endow the Fe_(3)O_(4)/h-YFeO_(3)composites with high performance and tunable functional properties for efficient electromagnetic absorption.展开更多
Fe–Ga sheets with large magnetostriction are required for improving the conversion efficiency under the ultra-high frequencymagnetic field. Trace Tb element doping can simultaneously improve the magnetostriction and ...Fe–Ga sheets with large magnetostriction are required for improving the conversion efficiency under the ultra-high frequencymagnetic field. Trace Tb element doping can simultaneously improve the magnetostriction and ductility of Fe–Ga alloy. However, the im-pact of trace Tb doping on the microstructure and magnetostriction of Fe–Ga thin sheets is an open question. In this paper, the effects oftrace Tb addition on the secondary recrystallization and magnetostriction of Fe–Ga thin sheets are systematically studied by comparing thecharacteristics evolution of precipitation, texture, and nanoinclusions. The results indicate that trace Tb addition accelerates the secondaryrecrystallization of Goss texture due to the combined action of the bimodal size distributed precipitates, smaller grains, and more HEGBsin primary recrystallization. After quenching at 900℃, the magnetostriction value in 0.07 at %Tb-doped Fe_(81)Ga_(19)thin sheets increases by 30% to that of Fe_(81)Ga_(19)thin sheets. The increase in magnetostriction is attributed to the decrease in the number of Tb-rich precipitates andthe higher density of the nanometer-sized modified-D0_(3)inclusions induced by the dissolving of trace Tb elements after quenching. Theseresults demonstrate a simple and efficient approach for preparing Fe–Ga thin sheets with a large magnetostrictive coefficient by a combin-ation of trace RE element addition and conventional rolling method.展开更多
As one of the common resins materials,PVC has the advantages of adjustable ardness,high mechanical performance,high corrosion resistance,good insulation,high transparency and low production cost.It is widely used in t...As one of the common resins materials,PVC has the advantages of adjustable ardness,high mechanical performance,high corrosion resistance,good insulation,high transparency and low production cost.It is widely used in the industry and agriculture sectors.However,due to its poor stability,PVC tends to have the reaction of degradation or crosslinking under the action of heat,light,oxygen and mechanical force,which make it difficult to be processed and used,its product color deepened and its mechanical property reduced.To solve the problem,certain heat stabilizer can be added when processing,to improve PVC's thermal decomposition temperature and expand its lifespan.The commercialized PVC heat stabilizers展开更多
The development of AI-Mn alloy protective coatings is reviewed in this paper,and factors affecting the corrosion resistance of Al-Mn alloy coatings are introduced.The effect of the addition of rare earths on the phase...The development of AI-Mn alloy protective coatings is reviewed in this paper,and factors affecting the corrosion resistance of Al-Mn alloy coatings are introduced.The effect of the addition of rare earths on the phase composition and surface flatness of AI-Mn alloy coating is emphasized.At the same time,the main existing problems and future development trends of rare earth AI-Mn alloy coating are briefly summarized.展开更多
Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and...Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and comprehensive utilization of the solid wastes of rare earth hydrometallurgy slag,electrolysis slag,Fe-based rare earth permanent magnetic materials,Co-based rare earth permanent magnetic materials,rare earth hydrogen storage materials,rare earth polishing powders and rare earth catalysts were ...展开更多
To investigate the effect of rare earth on size and distribution of TiB2 phase in aluminum alloy refiner,Al-5Ti-1B-RE master alloy was fabricated,and its microstructure and phase constitutions were investigated by the...To investigate the effect of rare earth on size and distribution of TiB2 phase in aluminum alloy refiner,Al-5Ti-1B-RE master alloy was fabricated,and its microstructure and phase constitutions were investigated by the combination of first principles calculations and experimental investigation.The calculated results reveal that Ce has the most effective modification ability due to the most positive adsorption energy and the largest charge transfer value compared with other rare earth elements.Results of experimental investigation indicate that the addition of rare earth in the Al-5Ti-1B alloys can greatly refine the particle size of TiB2,improve the distribution of particles and lead to better refinement effect than that of the Al-5Ti-1B alloys without rare earth.Moreover,Ce has the best optimization effect,which agrees well with the calculated results.展开更多
Using long-chain fatty acid as extractant, the process of removing the impurity element aluminum in the solution of praseodymium-neodymium chloride and the influence of extracting conditions were studied. The results ...Using long-chain fatty acid as extractant, the process of removing the impurity element aluminum in the solution of praseodymium-neodymium chloride and the influence of extracting conditions were studied. The results show that the amount of aluminum can be decreased from 728 to 14 mg·L -1 that is the 98% of total in the solution of praseodymium-neodymium chloride by one-stage extraction under the condition as follows: the concentration of rare earth is 100～200 g·L -1, the organic phase is 20% fatty acid -10% isooctanol -70% kerosene (V/V), saponification number is 20% with dense ammonia, and the extracting equilibrium time is 5～15 min. Under the same conditions, the extraction ratio of aluminum in the system of fatty acid is 3～5 times of that in naphthene acid. The fatty acid extractant is distinctly better than naphthene acid.展开更多
Application of rare earth in steels has gone through three stages in China.The investigation of rare earth adding method begun at the late 1970's has solved the technical problems caused by rare earth addition.Con...Application of rare earth in steels has gone through three stages in China.The investigation of rare earth adding method begun at the late 1970's has solved the technical problems caused by rare earth addition.Control ling sulphide morphology,several rare earth treated steel grades with improved properties have been developed and put into production.Rare earth exerts remarkable effect on the performance of low sulphur steel and on the hydrogen behavior in steel.Rare earth used for surface treatment of iron and steel materials expands rare earth utilization.展开更多
Preparing process was presented and the influences of concentration of acetic acid, reaction temperature, the ratio of cerium carbonate and acetic acid, heat preservation time to the yield of cerium acetate were discu...Preparing process was presented and the influences of concentration of acetic acid, reaction temperature, the ratio of cerium carbonate and acetic acid, heat preservation time to the yield of cerium acetate were discussed.The crystalline cerium acetate and rare earth acetate such as ( La, Ce, Pr, Nd) (Ac) 3, ( Ce, Pr, Nd) (Ac) 3, ( Pr, Nd, Er,Y) (Ac) 3 and yttrium acetate were prepared under this condition.The shape, structure and composition of the crystals were determined by the methods of SEM, TG-DTA, X-ray diffraction and chemical analysis.The optimum prepared conditions of cerium acetate were described.This prepared process has characteristics such as simple process route, low cost, high yield, good quality, no pollution to environment, etc.展开更多
Rare earth standardization was developed along with rare earth industry.In recent decades, great advances have been made in China rare earth industry.This paper describes the status of rare earth standardization, prob...Rare earth standardization was developed along with rare earth industry.In recent decades, great advances have been made in China rare earth industry.This paper describes the status of rare earth standardization, problems existed and ways to perfect.Now the number of Chinese Rare Earth Standards has increased to 232 with expanding of the categories and covering scope of rare earth products.But the present standard system cannot be completely suited with rare earth production and trade, and not keep pace with the advance of technology.Standards are important rules in world trade and must be acted on.展开更多
In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was prepared.The effect of the second phases,initial texture and deformation behavior on this low mechani...In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was prepared.The effect of the second phases,initial texture and deformation behavior on this low mechanical anisotropy was investigated.The results revealed that the alloy tube contains the high content(Mg1-xZnx)11Ce phase and the low content of Mg12Ce phase.These second phases are respectively incoherent and coherent with the Mg matrix,and their influence can be ignored.Additionally,the alloy tube exhibited a weak basal fiber texture,where the c-axis was aligned along the 0°∼30°tilt from TD to ED.Such a texture made the initial deformation(at 1.0%∼1.6%strain)of the three samples controlled by comparable basalslip.As deformation progressed(1.6∼9.0%strain),larger amounts of ETWs nucleated and gradually approached saturation in the three samples,re-orienting the c-axis to a 0°∼±30°deviation with respect to the loading directions.Meanwhile,the prismatic and pyramidal<c+a>slips replaced the dominant deformation progressively until fracture.Eventually,the similar deformation mechanisms determined by the weak initial texture in the three samples contribute to the comparable strain hardening rates,resulting in the low compressive anisotropy of the alloy tube.展开更多
The studies were made on the preparation processes of the rare earth metal and alloy target materials and their characterization. In this work the rare earth metals were prepared by electrolysis of the oxide in molten...The studies were made on the preparation processes of the rare earth metal and alloy target materials and their characterization. In this work the rare earth metals were prepared by electrolysis of the oxide in molten salt for Nd metal and metallothermic reduction of the fluorides for Gd, Tb, Dy metals. After vacuum refining and distillation purification these rare earth metals were used for manufacturing the element targets, mosaic targets and as the starting materials of preparing the rare earth-transition metal (RE-TM) alloy targets. The four kinds of Dy-FeCo, NdDy-FeCo, Tb-FeCo and GdTb-FeCo alloy targets with diameter of 100 mm and thickness of 3 mm were prepared using powder metallurgical technique. The oxygen content and microstructure of the prepared RE-TM cast alloys and sintered targets were analyzed. The features and requirements of the RE-TM alloy sputtering target materials were also discussed.展开更多
NdFeB magnet and samarium cobalt magnet are two important rare earth permanent magnetic materials.They are widely used in new energy vehicles,wind power generation,electronic equipment,medical equipment,aviation indus...NdFeB magnet and samarium cobalt magnet are two important rare earth permanent magnetic materials.They are widely used in new energy vehicles,wind power generation,electronic equipment,medical equipment,aviation industry,national defense and military industry,permanent magnet motor and other industries.展开更多
The cheap and easily available PVC products have been widely used in human life for its advantages of good corrosion resistance and high mechanical property.However,thermal stability is the most critical in PVC manufa...The cheap and easily available PVC products have been widely used in human life for its advantages of good corrosion resistance and high mechanical property.However,thermal stability is the most critical in PVC manufacturing.PVC is easily decomposed in oxygen atmosphere and at high temperature.Therefore,heat stabilizer has to be used during process to restrain or slow down the decomposition of PVC.展开更多
China has the largest reserves of rare earths in the world. Besides,it is a country with the large production,application and export volumes of rare earths.Today,Chinese rare earth products can meet the requirements b...China has the largest reserves of rare earths in the world. Besides,it is a country with the large production,application and export volumes of rare earths.Today,Chinese rare earth products can meet the requirements by different展开更多
基金Education Commission of Sichuan Province of China (2006A099)
文摘The iso-electric point of different rare earths （La, Ce, Y） doped anatase TiO2 was set out, and three organisms with different sur- face electrical properties （methylene blue trihydrate-positive electricity, methyl orange-negative electricity, methyl red-neutral electricity） were selected as photodegradable models. The result showed that the photocatalytic activity of 0.5wt.%Y ions doped anatase TiO2 was better than those of the others. The relationship between Zeta （ξ） potential and the photocatalytic activity of different RE doped anatase TiO2 were also investigated. The Y-doped anatase TiO2 was found with the special two iso-electric points and three ξ potential values.
文摘1.Export situation from January to June 20241.1 Overall export situation of rare earth products Export value of rare earth products showed a wholistic down trend affected by the continuousdecline in rare earth prices in the first half year,however,export volume increased.According to statistics from the General Administration of Customs,from January to June 2024,China's cumulative export of rare earth products was 29,095 tons,an increase of 11%year-on-year,with a cumulative export value of 256 million US dollars,a decrease of 43% year-on-year,Figure 1.
文摘The overall rare earth market was relatively stagnant in the first half of 2024,with mainstream rare earth prices downward..On the supply side:The production quotas for mining and separation allocated for light rare earths in the first half of 2024 was increased compared with that in the same period of 2023;Supply of raw materials was sufficient for separation enterprises;Recycling enterprises were operated under their capacity.
基金funded by the National Key R&D Program of China(2021YFA1501101)the National Natural Science Foundation of China(No.22471103,22425105,22201111,21931001,22221001,and 22271124)+5 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Special Fund Project of Guiding Scientific and Technological Innovation Development of Gansu Province(2019ZX-04)the 111 Project(B20027)as well as the National Natural Science Foundation of Gansu Province(22JR5RA470)the Fundamental Research Funds for the Central Universities(lzujbky-2023-eyt03)supported by the Agency for Science,Technology and Research(A*STAR)MTC Individual Research Grants(IRG)M22K2c0078.
文摘Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.
文摘The solid oxide fuel cell (SOFC) is a high-efficient and environmentally friendly power generation system.The rare earth oxide materials are used extensively in the manufacturing of SOFC components.In particular, the CeO2doped with Gd2O3 or Sm2O3, lanthanide perovskite oxides are indispensable and key materials for developing the intermediate temperature SOFC.The research and development status of application of high purity rare earth oxides in SOFC was overviewed.The rare earth oxide-based and -doped materials were discussed for the SOFC components.Concerning the rare earth oxides applicable to SOFC, several topics were also pointed out for further researching and developing.
基金supported by the National Natural Science Foundation of China(Nos.52122106 and 52027802)the“Pioneer”Research and Development Program of Zhejiang Province,China(No.2022C01230)+2 种基金the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,China(No.2021SZ-FR005)the Space Application System of China Manned Space Program(No.KJZ-YY-NCL03)the opening fund of Key Laboratory of Rare Earths,Chinese Academy of Sciences。
文摘Interface modulation is an important pathway for highly efficient electromagnetic wave absorption.Herein,tailored interfaces between Fe_(3)O_(4)particles and the hexagonal-YFeO_(3)(h-YFeO_(3))framework were constructed via facile self-assembly.The resulting interfa-cial electron rearrangement at the heterojunction led to enhanced dielectric and magnetic loss synergy.Experimental results and density function theory(DFT)simulations demonstrate a transition in electrical properties from a half-metallic monophase to metallic Fe_(3)O_(4)/h-YFeO_(3)composites,emphasizing the advantages of the formed heterointerface.The transformation of electron behavior is also accompan-ied by a redistribution of electrons at the Fe_(3)O_(4)/h-YFeO_(3)heterojunction,leading to the accumulation of localized electrons around the Y-O-Fe band bridge,consequently enhancing the polarization.A minimum reflection loss of-34.0 dB can be achieved at 12.0 GHz and 2.0 mm thickness with an effective bandwidth of 3.3 GHz due to the abundant interfaces,enhanced polarization,and rational impedance.Thus,the synergistic effects endow the Fe_(3)O_(4)/h-YFeO_(3)composites with high performance and tunable functional properties for efficient electromagnetic absorption.
基金financially supported by the National Natural Science Foundation of China (No. 52004164)the Funding Program of Science and Technology Department of Liaoning Province, China (No. 2023-MSLH-249)the Funding Program of Education Department of Liaoning P rovince, China (No. LMGD2023018)。
文摘Fe–Ga sheets with large magnetostriction are required for improving the conversion efficiency under the ultra-high frequencymagnetic field. Trace Tb element doping can simultaneously improve the magnetostriction and ductility of Fe–Ga alloy. However, the im-pact of trace Tb doping on the microstructure and magnetostriction of Fe–Ga thin sheets is an open question. In this paper, the effects oftrace Tb addition on the secondary recrystallization and magnetostriction of Fe–Ga thin sheets are systematically studied by comparing thecharacteristics evolution of precipitation, texture, and nanoinclusions. The results indicate that trace Tb addition accelerates the secondaryrecrystallization of Goss texture due to the combined action of the bimodal size distributed precipitates, smaller grains, and more HEGBsin primary recrystallization. After quenching at 900℃, the magnetostriction value in 0.07 at %Tb-doped Fe_(81)Ga_(19)thin sheets increases by 30% to that of Fe_(81)Ga_(19)thin sheets. The increase in magnetostriction is attributed to the decrease in the number of Tb-rich precipitates andthe higher density of the nanometer-sized modified-D0_(3)inclusions induced by the dissolving of trace Tb elements after quenching. Theseresults demonstrate a simple and efficient approach for preparing Fe–Ga thin sheets with a large magnetostrictive coefficient by a combin-ation of trace RE element addition and conventional rolling method.
文摘As one of the common resins materials,PVC has the advantages of adjustable ardness,high mechanical performance,high corrosion resistance,good insulation,high transparency and low production cost.It is widely used in the industry and agriculture sectors.However,due to its poor stability,PVC tends to have the reaction of degradation or crosslinking under the action of heat,light,oxygen and mechanical force,which make it difficult to be processed and used,its product color deepened and its mechanical property reduced.To solve the problem,certain heat stabilizer can be added when processing,to improve PVC's thermal decomposition temperature and expand its lifespan.The commercialized PVC heat stabilizers
文摘The development of AI-Mn alloy protective coatings is reviewed in this paper,and factors affecting the corrosion resistance of Al-Mn alloy coatings are introduced.The effect of the addition of rare earths on the phase composition and surface flatness of AI-Mn alloy coating is emphasized.At the same time,the main existing problems and future development trends of rare earth AI-Mn alloy coating are briefly summarized.
文摘Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and comprehensive utilization of the solid wastes of rare earth hydrometallurgy slag,electrolysis slag,Fe-based rare earth permanent magnetic materials,Co-based rare earth permanent magnetic materials,rare earth hydrogen storage materials,rare earth polishing powders and rare earth catalysts were ...
基金supported by the Natural Science Foundation of Inner Mongolia Autonomous Region(Grant No.2021MS05049)the Youth Fund Project of State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization(Grant No.2021Z2348)the Project of China North Rare Earth(Group)High-tech Co.,Ltd.(Grant No.2020H2177).
文摘To investigate the effect of rare earth on size and distribution of TiB2 phase in aluminum alloy refiner,Al-5Ti-1B-RE master alloy was fabricated,and its microstructure and phase constitutions were investigated by the combination of first principles calculations and experimental investigation.The calculated results reveal that Ce has the most effective modification ability due to the most positive adsorption energy and the largest charge transfer value compared with other rare earth elements.Results of experimental investigation indicate that the addition of rare earth in the Al-5Ti-1B alloys can greatly refine the particle size of TiB2,improve the distribution of particles and lead to better refinement effect than that of the Al-5Ti-1B alloys without rare earth.Moreover,Ce has the best optimization effect,which agrees well with the calculated results.
文摘Using long-chain fatty acid as extractant, the process of removing the impurity element aluminum in the solution of praseodymium-neodymium chloride and the influence of extracting conditions were studied. The results show that the amount of aluminum can be decreased from 728 to 14 mg·L -1 that is the 98% of total in the solution of praseodymium-neodymium chloride by one-stage extraction under the condition as follows: the concentration of rare earth is 100～200 g·L -1, the organic phase is 20% fatty acid -10% isooctanol -70% kerosene (V/V), saponification number is 20% with dense ammonia, and the extracting equilibrium time is 5～15 min. Under the same conditions, the extraction ratio of aluminum in the system of fatty acid is 3～5 times of that in naphthene acid. The fatty acid extractant is distinctly better than naphthene acid.
文摘Application of rare earth in steels has gone through three stages in China.The investigation of rare earth adding method begun at the late 1970's has solved the technical problems caused by rare earth addition.Control ling sulphide morphology,several rare earth treated steel grades with improved properties have been developed and put into production.Rare earth exerts remarkable effect on the performance of low sulphur steel and on the hydrogen behavior in steel.Rare earth used for surface treatment of iron and steel materials expands rare earth utilization.
文摘Preparing process was presented and the influences of concentration of acetic acid, reaction temperature, the ratio of cerium carbonate and acetic acid, heat preservation time to the yield of cerium acetate were discussed.The crystalline cerium acetate and rare earth acetate such as ( La, Ce, Pr, Nd) (Ac) 3, ( Ce, Pr, Nd) (Ac) 3, ( Pr, Nd, Er,Y) (Ac) 3 and yttrium acetate were prepared under this condition.The shape, structure and composition of the crystals were determined by the methods of SEM, TG-DTA, X-ray diffraction and chemical analysis.The optimum prepared conditions of cerium acetate were described.This prepared process has characteristics such as simple process route, low cost, high yield, good quality, no pollution to environment, etc.
文摘Rare earth standardization was developed along with rare earth industry.In recent decades, great advances have been made in China rare earth industry.This paper describes the status of rare earth standardization, problems existed and ways to perfect.Now the number of Chinese Rare Earth Standards has increased to 232 with expanding of the categories and covering scope of rare earth products.But the present standard system cannot be completely suited with rare earth production and trade, and not keep pace with the advance of technology.Standards are important rules in world trade and must be acted on.
基金supported by the National Natural Science Foundation of China(Nos.51974082,51901037)State Key Laboratory of Baiyunobo Rare Earth Resource Research and Comprehensive Utilization(No.2021H2279)Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project 2.0 of China,No.BP0719037).
文摘In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was prepared.The effect of the second phases,initial texture and deformation behavior on this low mechanical anisotropy was investigated.The results revealed that the alloy tube contains the high content(Mg1-xZnx)11Ce phase and the low content of Mg12Ce phase.These second phases are respectively incoherent and coherent with the Mg matrix,and their influence can be ignored.Additionally,the alloy tube exhibited a weak basal fiber texture,where the c-axis was aligned along the 0°∼30°tilt from TD to ED.Such a texture made the initial deformation(at 1.0%∼1.6%strain)of the three samples controlled by comparable basalslip.As deformation progressed(1.6∼9.0%strain),larger amounts of ETWs nucleated and gradually approached saturation in the three samples,re-orienting the c-axis to a 0°∼±30°deviation with respect to the loading directions.Meanwhile,the prismatic and pyramidal<c+a>slips replaced the dominant deformation progressively until fracture.Eventually,the similar deformation mechanisms determined by the weak initial texture in the three samples contribute to the comparable strain hardening rates,resulting in the low compressive anisotropy of the alloy tube.
基金Former the Ministry of Metallurgical Industry of China (BJ95-06-01)
文摘The studies were made on the preparation processes of the rare earth metal and alloy target materials and their characterization. In this work the rare earth metals were prepared by electrolysis of the oxide in molten salt for Nd metal and metallothermic reduction of the fluorides for Gd, Tb, Dy metals. After vacuum refining and distillation purification these rare earth metals were used for manufacturing the element targets, mosaic targets and as the starting materials of preparing the rare earth-transition metal (RE-TM) alloy targets. The four kinds of Dy-FeCo, NdDy-FeCo, Tb-FeCo and GdTb-FeCo alloy targets with diameter of 100 mm and thickness of 3 mm were prepared using powder metallurgical technique. The oxygen content and microstructure of the prepared RE-TM cast alloys and sintered targets were analyzed. The features and requirements of the RE-TM alloy sputtering target materials were also discussed.
文摘NdFeB magnet and samarium cobalt magnet are two important rare earth permanent magnetic materials.They are widely used in new energy vehicles,wind power generation,electronic equipment,medical equipment,aviation industry,national defense and military industry,permanent magnet motor and other industries.
文摘The cheap and easily available PVC products have been widely used in human life for its advantages of good corrosion resistance and high mechanical property.However,thermal stability is the most critical in PVC manufacturing.PVC is easily decomposed in oxygen atmosphere and at high temperature.Therefore,heat stabilizer has to be used during process to restrain or slow down the decomposition of PVC.
文摘China has the largest reserves of rare earths in the world. Besides,it is a country with the large production,application and export volumes of rare earths.Today,Chinese rare earth products can meet the requirements by different
