Grain boundary diffusion process(GBDP)serves as a promising approach in improving magnetic properties and thermal stability of Nd FeB permanent magnets.Herein,non-heavy rare earth Pr-Zn films deposited on the magnet s...Grain boundary diffusion process(GBDP)serves as a promising approach in improving magnetic properties and thermal stability of Nd FeB permanent magnets.Herein,non-heavy rare earth Pr-Zn films deposited on the magnet surface using DC-magnetron sputtering system are reported.The thermal stability and coercivity enhancement mechanism of Pr-Zn GBDP magnets were investigated.Results show that the coercivity of Pr-Zn GBDP magnet increases from 963.96 kA m^-1 to 1317.14 kA m^-1 without any remanence reduction.Notably,the demagnetization curve of Pr-Zn GBDP magnet still remains a high squareness ratio.The temperature coefficient of coercivity and anti-demagnetization ability of Pr-Zn GBDP magnet under high temperatures are improved after GBDP treatment.The well-optimized rare earth-rich(RE-rich)grain boundary phases and high effective anisotropy field of(Nd,RE)2 Fe14 B magnetic hardening layers surrounding main grains are the key factors to impact the magnetic properties and thermal stability of Nd FeB permanent magnets via GBDP treatment.展开更多
A method of co-sputtering deposition combined with physical masking was applied to the parallel preparation of a ternary Ti-NbZr system alloy. Sixteen independent specimens with varying compositions were obtained. The...A method of co-sputtering deposition combined with physical masking was applied to the parallel preparation of a ternary Ti-NbZr system alloy. Sixteen independent specimens with varying compositions were obtained. Their microstructure, phase structure,Young’s modulus, nanoindentation hardness, and electrochemical behavior in a phosphate buffer solution(PBS) were studied in detail. It was revealed that the Ti-Zr-Nb alloys possess a single BCC structure. As confirmed via nanoindentation tests, the Young’s modulus of the specimens ranged from 80.3 to 94.8 GPa and the nanoindentation hardness ranged from 3.6 to 5.0 GPa.By optimizing the composition of the specimens, the Ti34Zr52Nb14 alloy was made to possess the lowest modulus in this work(76.5 GPa). Moreover, the Ti34Zr52Nb14 alloy showed excellent corrosion resistance in PBS without any tendency for pitting at anodic potentials up to 1 Vsce. These preliminary advantages offer the opportunity to explore new orthopedic implant alloys based on Ti-Zr-Nb alloys. Moreover, this work provides an effective method for the parallel preparation of biomedical alloys.展开更多
采用直流磁控共溅射技术,在烧结态NdFeB磁体表面沉积一层非重稀土低熔点PrZn合金,在750℃×3 h进行真空热扩渗处理,500℃×2 h进行回火处理,研究此种工艺对磁体的磁性能、耐热性能及显微组织结构的影响。晶界扩散处理后,磁体在...采用直流磁控共溅射技术,在烧结态NdFeB磁体表面沉积一层非重稀土低熔点PrZn合金,在750℃×3 h进行真空热扩渗处理,500℃×2 h进行回火处理,研究此种工艺对磁体的磁性能、耐热性能及显微组织结构的影响。晶界扩散处理后,磁体在保持剩磁和方形度基本不变的情况下,矫顽力由963.96 k A·m^(-1)提高到1317.14 k A·m^(-1),即在原来的基础上增加了36.64%。磁体的耐热性得以提高,α_(Br)和β_(Hcj)均得以改善,α_(Br)由原样的-0.1188%·℃^(-1)降低到扩渗样的-0.1180%·℃^(-1),β_(Hcj)由原样的-0.5533%·℃^(-1)降低为扩渗样的-0.5133%·℃^(-1)。磁体显微组织结构的改善以及成分分布的优化,是晶界扩散处理后磁体矫顽力和耐热性得以改善的最主要原因。展开更多
Controllable and scalable preparation of electrocatalyst materials holds significant importance for their practical application.Magnetron sputtering is a highly effective synthesis method,known for its producing unifo...Controllable and scalable preparation of electrocatalyst materials holds significant importance for their practical application.Magnetron sputtering is a highly effective synthesis method,known for its producing uniform films and allowing easy control of component compositions.In this paper,we propose an in-situ synthesis method for layered double hydroxide(LDH)electrocatalysts through sacrificing magnetron sputtered films.The resulting FeCo-LDH catalyst demonstrated a low overpotential of only 300 mV at 10 mA·cm^(-2).Furthermore,we conducted spectroscopic analysis to investigate the surface changes of the catalysts during the oxygen evolution reaction(OER)process.Our findings indicated that the formation of Co oxyhydroxides plays a beneficial role in enhancing the catalytical performance of the FeCo-LDH for OER reaction.This restructuring strategy of converting a magnetron-sputtered sacrificial film into a catalytical LDH introduces a new avenue to the synthesis of transition metal-based electrocatalysts.展开更多
Refractory high-entropy alloys(HEAs)possess many useful properties such as high strength and high-temperature stability.So far,most studies on refractory HEAs have been limited to a few well-known compositions and on ...Refractory high-entropy alloys(HEAs)possess many useful properties such as high strength and high-temperature stability.So far,most studies on refractory HEAs have been limited to a few well-known compositions and on their coarse-grain bulk forms.Here we fabricate nanocrystalline(TiZrHf)_(x)(NbTa)_(1−x)HEA thin films with a large range of compositions(x=0.07–0.90)by the direct current(DC)magnetron co-sputtering technique and measure their mechanical properties using the nanoindentation method.All the as-deposited HEA thin films show a solid-solution body-centered cubic(bcc)structure.As the compositional ratio(x)increases,the elastic modulus decreases from 153 to 123 GPa,following the trend of the rule of mixture.As x increases,the hardness first decreases from 6.5 GPa(x=0.07)to the lowest value(4.6 GPa,x=0.48)and then increases to the highest value(7.1 GPa,x=0.90),showing a concave trend.The change in hardness might be attributed to the combinational influence caused by the atomic size and modulus effects,as well as the texture effect.The authors also propose a few open questions for future studies on this and related HEA systems.展开更多
Magnesium-ion batteries(MIBs)are promising alternatives to lithium-ion batteries due to their safety and high theoretical specific capacity,and the abundance of magnesium reserves.However,their anodes and electro-lyte...Magnesium-ion batteries(MIBs)are promising alternatives to lithium-ion batteries due to their safety and high theoretical specific capacity,and the abundance of magnesium reserves.However,their anodes and electro-lytes severely restrict the development of MIBs,so alloy-type anodes provide an effective strategy to circum-vent the surface passivation issue encountered with Mg metal in conventional electrolytes.Theoretically,a germanium anode can deliver a high specific capacity of 1476 mAh g?1,but hitherto,no experimental reports have described Ge in MIBs.Herein,we experimentally verified that Ge could reversibly react with Mg 2þions through the design of dual-phase Ge–Bi film electrodes fabricated by magnetron co-sputtering.Notably,a Ge 57 Bi 43 electrode delivered a high specific capacity of 847.5 mAh g?1,owing to the joint alloying reactions of Ge and Bi with Mg,which was much higher than the specific capacity of Bi(around 385 mAh g?1).Moreover,the Ge–Bi anode showed excellent rate performance,good cycling stability,and superior compatibility with conventional electrolytes such as Mg(TFSI)2.More importantly,the Mg storage mechanism of the Ge–Bi anode was unveiled by operando X-ray diffraction,and density functional theory calculations rationalized that the introduction of Bi to form Ge–Bi evidently decreased the defect formation energy and effectively boosted the electrochemical reactivity of Ge with Mg.展开更多
采用共溅射及分步溅射方法在涂钼的钠钙玻璃衬底上分别形成金属预制层,先后在低温及高温下对金属预制层进行合金后硫化,制备了铜锌锡硫（Cu2Zn SnS4,CZTS）薄膜。研究了薄膜的晶体结构、表面和截面形貌、元素组分、薄膜中的相纯度及元...采用共溅射及分步溅射方法在涂钼的钠钙玻璃衬底上分别形成金属预制层,先后在低温及高温下对金属预制层进行合金后硫化,制备了铜锌锡硫（Cu2Zn SnS4,CZTS）薄膜。研究了薄膜的晶体结构、表面和截面形貌、元素组分、薄膜中的相纯度及元素的化学状态。结果表明：共溅射预制层得到的CZTS薄膜的表面及截面形貌优于分步溅射预制层得到的CZTS薄膜。用紫外-可见分光光度计与Hall测试系统表征了CZTS薄膜的光电特性,发现在200℃退火15 h能有效降低CZTS薄膜的缺陷态密度,增加CZTS薄膜中的载流子迁移率和扩散系数。研究结果表明,采用共溅射制备CZTS薄膜太阳电池性能优于分步溅射法,且经过退火处理的CZTS薄膜制备的电池特性均得到有效提高。基于分步溅射法制备的CZTS吸收层制备的电池开路电压为722 m V,短路电流密度为11.2 mA/cm2,最高转换效率为3.22%;基于共溅射法制备的CZTS吸收层制备的电池开路电压为637 m V,短路电流密为15.0 mA/cm2,最高转换效率为3.88%。展开更多
TiN x/CF y composite coatings were prepared by RF magnetron co-sputtering using twin cylindrical tube targets with Ar and N 2 mixtures.The composition of the coatings deposited at various positions was analyzed by X-r...TiN x/CF y composite coatings were prepared by RF magnetron co-sputtering using twin cylindrical tube targets with Ar and N 2 mixtures.The composition of the coatings deposited at various positions was analyzed by X-ray photoelectron spectroscopy（XPS） and Rutherford back-scattering spectrometry（RBS）.The results revealed that the composition of the deposited coatings has a wide range of TiN x and CFy contents at different deposition positions,which leads to different structures and performances.The hardness of the composite coatings increases from 32 to 1603 HV with increasing the TiN x concentration.The static contact angle of water ranges from 20° to 102° and decreases upon the incorporation of more TiN x into the CF y polymer.The presence of the CF y groups enhances the contact angle between the coating and the solutions dropped onto it,which could effectively protect the coating from corrosion and improve the wear resistance properties in high relative humidity（RH）.The brittleness of the coatings decreases due to the softness of the CF y component,which can bear most of the load and result in less probability of crack formation.XPS results demonstrate the existence of a Ti-（C N） chemical bond in the composite coatings,which improves the wear resistance of the coatings.It is indicated that the wear resistance of the TiN x/CF y coatings is independent of the hardness.However,these properties depend on the uniform structure and the existence of chemical bonding between the TiN x and CF y phases.Moreover,a specific ratio between the soft CF y phase and the hard TiN x phase can produce coatings with good wear resistance.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51561009)the General Program of National Natural Science Foundation of Jiangxi Province(No.20192BAB206004)+2 种基金the Higher School Science and Technology Landing Project of Jiangxi Province(No.KJLD14043)the Doctoral Start-up Foundation of Jiangxi University of Science and Technology(No.3401223391)the China Scholarship Council(No.201703000006)for funding to visit Nanyang Technological University,Singapore.
文摘Grain boundary diffusion process(GBDP)serves as a promising approach in improving magnetic properties and thermal stability of Nd FeB permanent magnets.Herein,non-heavy rare earth Pr-Zn films deposited on the magnet surface using DC-magnetron sputtering system are reported.The thermal stability and coercivity enhancement mechanism of Pr-Zn GBDP magnets were investigated.Results show that the coercivity of Pr-Zn GBDP magnet increases from 963.96 kA m^-1 to 1317.14 kA m^-1 without any remanence reduction.Notably,the demagnetization curve of Pr-Zn GBDP magnet still remains a high squareness ratio.The temperature coefficient of coercivity and anti-demagnetization ability of Pr-Zn GBDP magnet under high temperatures are improved after GBDP treatment.The well-optimized rare earth-rich(RE-rich)grain boundary phases and high effective anisotropy field of(Nd,RE)2 Fe14 B magnetic hardening layers surrounding main grains are the key factors to impact the magnetic properties and thermal stability of Nd FeB permanent magnets via GBDP treatment.
基金supported by the National Natural Science Foundation of China(Grant No.51671020)
文摘A method of co-sputtering deposition combined with physical masking was applied to the parallel preparation of a ternary Ti-NbZr system alloy. Sixteen independent specimens with varying compositions were obtained. Their microstructure, phase structure,Young’s modulus, nanoindentation hardness, and electrochemical behavior in a phosphate buffer solution(PBS) were studied in detail. It was revealed that the Ti-Zr-Nb alloys possess a single BCC structure. As confirmed via nanoindentation tests, the Young’s modulus of the specimens ranged from 80.3 to 94.8 GPa and the nanoindentation hardness ranged from 3.6 to 5.0 GPa.By optimizing the composition of the specimens, the Ti34Zr52Nb14 alloy was made to possess the lowest modulus in this work(76.5 GPa). Moreover, the Ti34Zr52Nb14 alloy showed excellent corrosion resistance in PBS without any tendency for pitting at anodic potentials up to 1 Vsce. These preliminary advantages offer the opportunity to explore new orthopedic implant alloys based on Ti-Zr-Nb alloys. Moreover, this work provides an effective method for the parallel preparation of biomedical alloys.
文摘采用直流磁控共溅射技术,在烧结态NdFeB磁体表面沉积一层非重稀土低熔点PrZn合金,在750℃×3 h进行真空热扩渗处理,500℃×2 h进行回火处理,研究此种工艺对磁体的磁性能、耐热性能及显微组织结构的影响。晶界扩散处理后,磁体在保持剩磁和方形度基本不变的情况下,矫顽力由963.96 k A·m^(-1)提高到1317.14 k A·m^(-1),即在原来的基础上增加了36.64%。磁体的耐热性得以提高,α_(Br)和β_(Hcj)均得以改善,α_(Br)由原样的-0.1188%·℃^(-1)降低到扩渗样的-0.1180%·℃^(-1),β_(Hcj)由原样的-0.5533%·℃^(-1)降低为扩渗样的-0.5133%·℃^(-1)。磁体显微组织结构的改善以及成分分布的优化,是晶界扩散处理后磁体矫顽力和耐热性得以改善的最主要原因。
基金support from the National Natural Science Foundation of China(Nos.52250710159,51731008,51671163)。
文摘Controllable and scalable preparation of electrocatalyst materials holds significant importance for their practical application.Magnetron sputtering is a highly effective synthesis method,known for its producing uniform films and allowing easy control of component compositions.In this paper,we propose an in-situ synthesis method for layered double hydroxide(LDH)electrocatalysts through sacrificing magnetron sputtered films.The resulting FeCo-LDH catalyst demonstrated a low overpotential of only 300 mV at 10 mA·cm^(-2).Furthermore,we conducted spectroscopic analysis to investigate the surface changes of the catalysts during the oxygen evolution reaction(OER)process.Our findings indicated that the formation of Co oxyhydroxides plays a beneficial role in enhancing the catalytical performance of the FeCo-LDH for OER reaction.This restructuring strategy of converting a magnetron-sputtered sacrificial film into a catalytical LDH introduces a new avenue to the synthesis of transition metal-based electrocatalysts.
基金support from the Discovery Grants Program(No.RGPIN-2018-05731)the Natural Sciences and Engineering Research Council of Canada(NSERC)+3 种基金New Frontiers in Research Fund-Exploration(No.NFRFE-2019-00603)Dean’s Spark Assistant Professorship in the Faculty of Applied Science&Engineering atUniversity of Toronto.M.J.R.H.acknowledges the financial support from Vanier Canada Graduate Scholarship(NSERC),Ontario Graduate Scholarship,and Queen Elizabeth II/Eleanor and Burnett Thall Graduate ScholarshipCanada Foundation for Innovation(CFI)-John R.Evans Leaders Fund(JELF)Project#38044.
文摘Refractory high-entropy alloys(HEAs)possess many useful properties such as high strength and high-temperature stability.So far,most studies on refractory HEAs have been limited to a few well-known compositions and on their coarse-grain bulk forms.Here we fabricate nanocrystalline(TiZrHf)_(x)(NbTa)_(1−x)HEA thin films with a large range of compositions(x=0.07–0.90)by the direct current(DC)magnetron co-sputtering technique and measure their mechanical properties using the nanoindentation method.All the as-deposited HEA thin films show a solid-solution body-centered cubic(bcc)structure.As the compositional ratio(x)increases,the elastic modulus decreases from 153 to 123 GPa,following the trend of the rule of mixture.As x increases,the hardness first decreases from 6.5 GPa(x=0.07)to the lowest value(4.6 GPa,x=0.48)and then increases to the highest value(7.1 GPa,x=0.90),showing a concave trend.The change in hardness might be attributed to the combinational influence caused by the atomic size and modulus effects,as well as the texture effect.The authors also propose a few open questions for future studies on this and related HEA systems.
基金The authors acknowledge the support by National Natural Science Foundation of China(51871133)Taishan Scholar Foundation of Shan-dong Province,the Key Research and Development Program of Shandong Province(2021ZLGX01)the program of Jinan Science and Tech-nology Bureau(2019GXRC001).
文摘Magnesium-ion batteries(MIBs)are promising alternatives to lithium-ion batteries due to their safety and high theoretical specific capacity,and the abundance of magnesium reserves.However,their anodes and electro-lytes severely restrict the development of MIBs,so alloy-type anodes provide an effective strategy to circum-vent the surface passivation issue encountered with Mg metal in conventional electrolytes.Theoretically,a germanium anode can deliver a high specific capacity of 1476 mAh g?1,but hitherto,no experimental reports have described Ge in MIBs.Herein,we experimentally verified that Ge could reversibly react with Mg 2þions through the design of dual-phase Ge–Bi film electrodes fabricated by magnetron co-sputtering.Notably,a Ge 57 Bi 43 electrode delivered a high specific capacity of 847.5 mAh g?1,owing to the joint alloying reactions of Ge and Bi with Mg,which was much higher than the specific capacity of Bi(around 385 mAh g?1).Moreover,the Ge–Bi anode showed excellent rate performance,good cycling stability,and superior compatibility with conventional electrolytes such as Mg(TFSI)2.More importantly,the Mg storage mechanism of the Ge–Bi anode was unveiled by operando X-ray diffraction,and density functional theory calculations rationalized that the introduction of Bi to form Ge–Bi evidently decreased the defect formation energy and effectively boosted the electrochemical reactivity of Ge with Mg.
文摘采用共溅射及分步溅射方法在涂钼的钠钙玻璃衬底上分别形成金属预制层,先后在低温及高温下对金属预制层进行合金后硫化,制备了铜锌锡硫（Cu2Zn SnS4,CZTS）薄膜。研究了薄膜的晶体结构、表面和截面形貌、元素组分、薄膜中的相纯度及元素的化学状态。结果表明：共溅射预制层得到的CZTS薄膜的表面及截面形貌优于分步溅射预制层得到的CZTS薄膜。用紫外-可见分光光度计与Hall测试系统表征了CZTS薄膜的光电特性,发现在200℃退火15 h能有效降低CZTS薄膜的缺陷态密度,增加CZTS薄膜中的载流子迁移率和扩散系数。研究结果表明,采用共溅射制备CZTS薄膜太阳电池性能优于分步溅射法,且经过退火处理的CZTS薄膜制备的电池特性均得到有效提高。基于分步溅射法制备的CZTS吸收层制备的电池开路电压为722 m V,短路电流密度为11.2 mA/cm2,最高转换效率为3.22%;基于共溅射法制备的CZTS吸收层制备的电池开路电压为637 m V,短路电流密为15.0 mA/cm2,最高转换效率为3.88%。
基金supported by the National Science Foundation for Young Scholars of China (Grant Nos.51302054 and 51205056)the Natural Science Foundation for Young Scholars of Heilongjiang Province of China (Grant No.QC2012C008)the Natural Science Foundation of Heilongjiang Province (Grant No.E201356)
文摘TiN x/CF y composite coatings were prepared by RF magnetron co-sputtering using twin cylindrical tube targets with Ar and N 2 mixtures.The composition of the coatings deposited at various positions was analyzed by X-ray photoelectron spectroscopy（XPS） and Rutherford back-scattering spectrometry（RBS）.The results revealed that the composition of the deposited coatings has a wide range of TiN x and CFy contents at different deposition positions,which leads to different structures and performances.The hardness of the composite coatings increases from 32 to 1603 HV with increasing the TiN x concentration.The static contact angle of water ranges from 20° to 102° and decreases upon the incorporation of more TiN x into the CF y polymer.The presence of the CF y groups enhances the contact angle between the coating and the solutions dropped onto it,which could effectively protect the coating from corrosion and improve the wear resistance properties in high relative humidity（RH）.The brittleness of the coatings decreases due to the softness of the CF y component,which can bear most of the load and result in less probability of crack formation.XPS results demonstrate the existence of a Ti-（C N） chemical bond in the composite coatings,which improves the wear resistance of the coatings.It is indicated that the wear resistance of the TiN x/CF y coatings is independent of the hardness.However,these properties depend on the uniform structure and the existence of chemical bonding between the TiN x and CF y phases.Moreover,a specific ratio between the soft CF y phase and the hard TiN x phase can produce coatings with good wear resistance.
