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Preparation of lead-free free-cutting graphite brasses by graphitization of cementite 被引量:1
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作者 卓海鸥 唐建成 +1 位作者 薛滢妤 叶楠 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第10期3252-3257,共6页
Graphite brasses were prepared by graphitizing annealing of cast brasses containing cementite particles,which were in-situ formed during the fasting process.The eutectic cast iron as carbon source was added into commo... Graphite brasses were prepared by graphitizing annealing of cast brasses containing cementite particles,which were in-situ formed during the fasting process.The eutectic cast iron as carbon source was added into common brasses by casting.SEM and EDS were used to analyze the microstructure of graphite brasses,and the relationship between the microstructure and machinability was investigated.The results show that graphite particles are formed by the decomposition of cementite particles in cast brasses.The graphite particles are uniformly dispersed in the brass matrix with the average size of 5.0 μm and the volume fraction of ~1.1%.The machinability in the graphite brass is dramatically increased relative to the common brass,because of the lubricating properties of graphite particles and its role in chip breaking.The workpiece surface of the graphite brasses chips is smooth and burr-free,and the chips of graphite brasses are short(C-shape) and discontinuous,which is much better than that of the long spiral chips of common brasses. 展开更多
关键词 lead-free graphite brass graphitization annealing microstructure machinability
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Ligand modulation of active center to promote lead-free Cs_(2)AgInCl_(6)photocatalytic CO_(2)reduction
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作者 Baofei Sun Wei Chen +10 位作者 Yanyi Huang Daofu Wu Heng Luo Faguang Kuang Hongmei Ran Yichen Liu Liqin Gao Jinchen Zhou Bo Gao Qiang Huang Xiaosheng Tang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期660-669,I0015,共11页
Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand ... Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand impedes the adsorption and activation of CO_(2)molecules in practical applications.Here,a ligand modulation technology is employed to enhance the photocatalytic CO_(2)reduction activity of lead-free Cs_(2)AgInCl_(6)microcrystals(MCs).The Cs_(2)AgInCl_(6)MCs passivated by Oleic acid(OLA)and Octanoic acid(OCA)are used for photocatalytic CO_(2)reduction.The results show that the surface defects and electronic properties of Cs_(2)AgInCl_(6)MCs can be adjusted through ligand modulation.Compared with the OLA-Cs_(2)AgInCl_(6),the OCA-Cs_(2)AgInCl_(6)catalyst demonstrated a significant improvement in the catalytic yield of CO and CH_(4).The CO and CH_(4)catalytic yields of OCA-Cs_(2)AgInCl_(6)reached 171.88 and34.15μmol g^(-1)h^(-1)which were 2.03 and 12.98 times higher than those of OLA-Cs_(2)AgInCl_(6),and the total electron consumption rate of OCA-Cs_(2)AgInCl_(6)was 615.2μmol g^(-1)h^(-1)which was 3.25 times higher than that of OLA-Cs_(2)AgInCl_(6).Furthermore,in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs_(2)AgInCl_(6)MCs induced by ligand modulation.This study illustrates the potential of lead-free Cs_(2)AgInCl_(6)MCs for efficient photocatalytic CO_(2)reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts. 展开更多
关键词 Surface ligand Photocatalysis CO_(2)reduction lead-free perovskite Reactive mechanism
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Mechanical and Electrical Properties of Some Sn-Zn Based Lead-Free Quinary Alloys
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作者 Shihab Uddin Md. Abdul Gafur +1 位作者 Suraya Sabrin Soshi Mohammad Obaidur Rahman 《Materials Sciences and Applications》 2024年第7期213-227,共15页
Although there are many lead-free soldering alloys on the market, none of them have ideal qualities. The researchers are combining binary alloys with a variety of additional materials to create the soldering alloys’ ... Although there are many lead-free soldering alloys on the market, none of them have ideal qualities. The researchers are combining binary alloys with a variety of additional materials to create the soldering alloys’ features. The eutectic Sn-9Zn alloy is among them. This paper investigated the mechanical and electrical properties of Sn-9Zn-x (Ag, Cu, Sb);{x = 0.2, 0.4, and 0.6} lead-free solder alloys. The mechanical properties such as elastic modulus, ultimate tensile strength (UTS), yield strength (YS), and ductility were examined at the strain rates in a range from 4.17 10−3 s−1 to 208.5 10−3 s−1 at room temperature. It is found that increasing the content of the alloying elements and strain rate increases the elastic modulus, ultimate tensile strength, and yield strength while the ductility decreases. The electrical conductivity of the alloys is found to be a little smaller than that of the Sn-9Zn eutectic alloy. 展开更多
关键词 lead-free Solder Strain Rate Ultimate Tensile Strength DUCTILITY Electrical Conductivity
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Large Energy Capacitive High-Entropy Lead-Free Ferroelectrics 被引量:8
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作者 Liang Chen Huifen Yu +5 位作者 Jie Wu Shiqing Deng Hui Liu Lifeng Zhu He Qi Jun Chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第5期69-82,共14页
Advanced lead-free energy storage ceramics play an indispensable role in next-generation pulse power capacitors market.Here,an ultrahigh energy storage density of~13.8 J cm^(-3)and a large efficiency of~82.4%are achie... Advanced lead-free energy storage ceramics play an indispensable role in next-generation pulse power capacitors market.Here,an ultrahigh energy storage density of~13.8 J cm^(-3)and a large efficiency of~82.4%are achieved in high-entropy lead-free relaxor ferroelectrics by increasing configuration entropy,named high-entropy strategy,realizing nearly ten times growth of energy storage density compared with low-entropy material.Evolution of energy storage performance and domain structure with increasing configuration entropy is systematically revealed for the first time.The achievement of excellent energy storage properties should be attributed to the enhanced random field,decreased nanodomain size,strong multiple local distortions,and improved breakdown field.Furthermore,the excellent frequency and fatigue stability as well as charge/discharge properties with superior thermal stability are also realized.The significantly enhanced comprehensive energy storage performance by increasing configuration entropy demonstrates that high entropy is an effective but convenient strategy to design new high-performance dielectrics,promoting the development of advanced capacitors. 展开更多
关键词 High-entropy Energy storage lead-free Relaxor ferroelectrics Capacitors
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Photo-and Electrocatalytic CO_(2)Reduction Based on Stable Lead-Free Perovskite Cs2PdBr6 被引量:1
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作者 Daofu Wu Cheng Wang +7 位作者 Benjun Huo Ke Hu Xinchun Mao Zhigang Geng Qiang Huang Wenxia Zhang Jie Zeng Xiaosheng Tang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第5期364-371,共8页
All-inorganic lead-free palladium(Pd)halogen perovskites with prominent optoelectronic properties provide admirable potential for selective photo-and electroreduction of CO_(2).But it remains unachieved for effectivel... All-inorganic lead-free palladium(Pd)halogen perovskites with prominent optoelectronic properties provide admirable potential for selective photo-and electroreduction of CO_(2).But it remains unachieved for effectively converting the CO_(2)to CO with high selectivity on Pd-based perovskites driven by solar light or electricity.Herein,high-quality Cs_(2)PdBr_(6)microcrystals and nanocrystals were synthesized through a facile antisolvent method.Among all the reported pure-phase perovskites,the Cs_(2)PdBr_(6)nanocrystals synthesized at 50℃performed the highest effectiveness on CO_(2)to CO conversion generating 73.8μmol g^(-1)of CO yield with 100%selectivity under visible light illumination(λ>420 nm)for 3 h.Meanwhile,for the first time,we report a new application of lead-free perovskites,in which they are applied to electrocatalysis of CO_(2)reduction reaction.Noticeably,they showed significant electrocatalytic activity(Faradaic yield:78%for CO)and operation stability(10 h).And the surface reaction intermediates were dynamically monitored and precisely unraveled according to the in situ diffuse reflectance infrared Fourier transform spectra investigation.In combination with the density functional theory calculation,the reaction mechanism and pathways were revealed.This work not only provides significant strategies to enhance the photocatalytic performance of perovskites,but also shows excellent potential for their application in electrocatalysis. 展开更多
关键词 CO_(2)reduction CRYSTALLINITY lead-free perovskites morphology photocatalysis reaction mechanism
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Efficient Environment-friendly Lead-free Tin Perovskite Solar Cells Enabled by Incorporating 4-Fluorobenzylammonium Iodide Additives
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作者 Shengli Zou Shengqiang Ren +8 位作者 Yiting Jiang Yuanfang Huang Wenwu Wang Changlei Wang Cong Chen Xia Hao Lili Wu Jingquan Zhang Dewei Zhao 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第6期318-326,共9页
Development of tin(Sn)-based perovskite solar cells(PSCs)largely lags behind that of lead counterparts due to fast crystallization process of Sn perovskite and numerous defects in both bulk and surface of Sn perovskit... Development of tin(Sn)-based perovskite solar cells(PSCs)largely lags behind that of lead counterparts due to fast crystallization process of Sn perovskite and numerous defects in both bulk and surface of Sn perovskite films.Herein,this work reports a facile strategy of introducing 4-fluorobenzylammonium iodide(FBZAI)as additives into Sn perovskite precursor to synergistically modulate the roles of benzylamine and fluorine in Sn-based PSCs.Incorporation of FBZAI can increase crystallinity,passivate defects,and inhibit the oxidation of Sn^(2+),leading to suppression of nonradiative recombination and enhancement of charge transport and collection in devices.As a result,the best-performing Sn-based PSC with the FBZAI additive achieves the maximum PCE of 13.85%with the enhanced fill factor of 77.8%and open-circuit voltage of 0.778 V.Our unencapsulated device exhibits good stability by maintaining 95%of its initial PCE after 160 days of storage. 展开更多
关键词 4-fluorobenzylammonium iodide defect passivation lead-free Sn perovskites perovskite solar cells stability
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Air-Stable,Eco-Friendly RRAMs Based on Lead-Free Cs_(3)Bi_(2)Br_(9)Perovskite Quantum Dots for High-Performance Information Storage
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作者 Xiaofei Cao Zhuangzhuang Ma +4 位作者 Teng Cheng Yadong Wang Zhifeng Shi Jizheng Wang Li Zhang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第5期406-414,共9页
Development of lead-free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory(RRAM)fields.However,their inferior memory properties compared with the lead-ba... Development of lead-free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory(RRAM)fields.However,their inferior memory properties compared with the lead-based analogs hinder their commercialization.Herein,the lead-free Cs_(3)Bi_(2)Br_(9)perovskite quantum dot(PQD)-based RRAMs are reported with outstanding memory performance,where Cs_(3)Bi_(2)Br_(9)quantum dots(QDs)are synthesized via a modified ligand-assisted recrystallization process.This is the first report of applying Cs_(3)Bi_(2)Br_(9)QDs as the switching layer for RRAM device.The Cs_(3)Bi_(2)Br_(9)QD device demonstrates nonvolatile resistive switching(RS)effect with large ON/OFF ratio of 105,low set voltage of-0.45 V,as well as good reliability,reproducibility,and flexibility.Concurrently,the device exhibits the notable tolerance toward moisture,heat and light illumination,and long-term stability of 200 days.More impressively,the device shows the reliable light-modulated RS behavior,and therefrom the logic gate operations including"AND"and"OR"are implemented,foreboding its prospect in logic circuits integrated with storage and computation.Such multifunctionality of device could be derived from the unique 2D layered crystal structure,small particle size,quantum confinement effect,and photoresponse of Cs_(3)Bi_(2)Br_(9)QDs.This work provides the strategy toward the high-performance RRAMs based on stable and eco-friendly perovskites for future applications. 展开更多
关键词 air stability high memory performance lead-free perovskite quantum dots light-assisted logic gate operation RRAM devices
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Stable yellow light emission from lead-free copper halides single crystals for visible light communication
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作者 Baiqian Wang Yuru Tang +6 位作者 Xin Yang Wensi Cai Ru Li Wen Ma Shuangyi Zhao Chen Chen Zhigang Zang 《Nano Materials Science》 EI CAS CSCD 2023年第1期78-85,共8页
Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and th... Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and the available perovskites yellow LEDs suffer from the instability. Herein, a pressure-assisted cooling method is proposed to grow lead-free CsCu2I3single crystals, which possess uniform surface morphology and enhanced photoluminescence quantum yield(PLQY) stability, with only 10% PLQY losses after being stored in air after 5000 h.Then, the single crystals used for yellow LEDs without encapsulation exhibit a decent Correlated Color Temperature(CCT) of 4290 K, a Commission Internationale de l’Eclairage(CIE) coordinate of(0.38, 0.41), and an excellent 570-h operating stability under heating temperature of 100°C. Finally, the yellow LEDs facilitate the application in wireless visible light communication(VLC), which show a-3 dB bandwidth of 21.5 MHz and a high achievable data rate of 219.2 Mbps by using orthogonal frequency division multiplexing(OFDM) modulation with adaptive bit loading. The present work not only promotes the development of lead-free single crystals, but also inspires the potential of CsCu2I3in the field of yellow illumination and wireless VLC. 展开更多
关键词 lead-free copper halides Single crystals Yellow light-emitting diodes Visible light communication(VLC)
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First Principle Study of Cesium-based Lead-free Halide Double Perovskites
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作者 郑伟 甘小燕 +4 位作者 DU Dingjin WANG Yajie DAI Siqi GUO Liling LIU Hanxing 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第3期520-529,共10页
Inorganic halide double perovskites A_(2)B'B"X_(6) have gained significant interests for their diverse composition,stable physicochemical properties,and potential for photoelectric applications.The influences... Inorganic halide double perovskites A_(2)B'B"X_(6) have gained significant interests for their diverse composition,stable physicochemical properties,and potential for photoelectric applications.The influences of trivalent and monovalent cations on the formation energy,decomposition energy,electronic structure and optical properties of cesium-based lead-free Cs^(+)_(2)B'B"Br_(6) (B'=Na^(+),In^(+)Cu^(+),or Ag^(+);B"=Bi^(3),Sb^(3+),In^(3+)) are systematically studied.In view of the analysis and results of the selected double perovskites,for the double perovskites with different B-site trivalent cation,the band gap increases in the order of Cs_(2)AgInBr_(6),Cs_(2)AgSbBr_(6) and Cs_(2)AgBiBr_(6),with Cs_(2)AgBiBr_(6) possessing the highest thermodynamic stability.Therefore,the Bi-based perovskites are further studied to elucidate the effect of monovalent cation on their stability and electronics.Results show that the thermodynamic stability rises in the sequence of Cs_(2)NaBiBr_(6),Cs_(2)InBiBr_(6),Cs_(2)AgBiBr_(6) and Cs_(2)CuBiBr_(6).Notably,Cs_(2)CuBiBr_(6) exhibits a relatively narrow and appropriate band gap of 1.4634 eV,together with the highest absorption coefficient than other compounds,suggesting that Cs_(2)CuBiBr_(6) is a promising light absorbing material that can be further explored experimentally and be applied to optoelectronic devices.Our research offers theoretical backing for the potential optoelectronic application of cesium-based lead-free halide double perovskites in solar energy conversion. 展开更多
关键词 lead-free double perovskites density functional theory Cs_(2)B'B"Br_(6) STABILITY electronic properties optical property STABILITY
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Research of Lead-free Na_(0.5)Bi_(0.5)TiO_(3)-BaTiO_(3)System Piezoelectric Ceramics
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作者 ZHANG Weifeng LIU Ming 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第2期325-329,共5页
To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparat... To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparation condition and piezoelectric properties of the samples were investigated.The XRD results show that the fabric transites from rhombohedral to tetragonal gradually with the substitution of the Ba^(2+).The morphotropic phase boundaries(MPB)exists in the composition range of 0.06. 展开更多
关键词 lead-free piezoelectric ceramic Na_(0.5)Bi_(0.5)TiO_(3) BaTiO_(3) piezoelectric performance
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Effect of Strain Rate on Tensile Behavior of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} Lead-Free Solder Alloys
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作者 Shihab Uddin Md. Abdul Gafur Mohammad Obaidur Rahman 《Materials Sciences and Applications》 CAS 2023年第4期273-283,共11页
The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carrie... The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carried out at room temperature at the strain rate of 4.17 × 10<sup>-3</sup> s<sup>-1</sup>, 20.85 × 10<sup>-3</sup> s<sup>-1</sup>, and 208.5 × 10<sup>-3</sup> s<sup>-1</sup>. It is seen that the tensile strength increases and the ductility decrease with increasing the strain rate over the investigated range. From the strain rate change test results, the strain sensitivity values are found in the range of 0.0831 to 0.1455 due to the addition of different alloying elements. 展开更多
关键词 lead-free Solder Strain Rate Strain Sensitivity DUCTILITY Tensile Properties
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Effects of phosphorus addition on the properties of Sn-9Zn lead-free solder alloy 被引量:7
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作者 Hui-zhen Huang Xiu-qin Wei +1 位作者 Dun-qiang Tan Lang Zhou 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第6期563-567,共5页
This article explores tile effects of phosphorus addition on the wettability between Sn-9Zn solder alloy and Cu substrates, the oxidation behavior and the corrosion behavior of Sn-9Zn solder alloy. Spreading test was ... This article explores tile effects of phosphorus addition on the wettability between Sn-9Zn solder alloy and Cu substrates, the oxidation behavior and the corrosion behavior of Sn-9Zn solder alloy. Spreading test was used to characterize the wettability of Sn-9Zn-xP solder alloys to Cu substrates. The oxidation and corrosion behaviors of Sn- 9Zn-xP solder alloys were determined by means of weight gaining, and secondary ion mass spectrometry was used to analyze the oxygen content. The role and mechanism of P in the solder alloys were also discussed. It is found that the addition of P can significantly improve the wettability of the solder alloys. Incorporating P into Sn-9Zn solder alloy obviously decreases the oxygen content and enhances the oxidation and corrosion resistance. Microstructure observations show that an appropriate amount of P can greatly refine coarse rod-like Zn-rich phases in Sn-gZn solder alloy. 展开更多
关键词 lead-free solder PHOSPHORUS WETTABILITY oxidntion CORROSION
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Effect of diode-laser parameters on shear force of micro-joints soldered with Sn-Ag-Cu lead-free solder on Au/Ni/Cu pad 被引量:6
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作者 王俭辛 薛松柏 +3 位作者 方典松 鞠金龙 韩宗杰 姚立华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2006年第6期1374-1378,共5页
Soldering experiments with Sn-3.5Ag-0.5Cu lead-free solder on Au/Ni/Cu pad were carried out by means of diode-laser and IR reflow soldering methods respectively.The influence of different heating methods as well as ou... Soldering experiments with Sn-3.5Ag-0.5Cu lead-free solder on Au/Ni/Cu pad were carried out by means of diode-laser and IR reflow soldering methods respectively.The influence of different heating methods as well as output power of diode-laser on shear force of micro-joints was studied and the relationship between the shear force and microstructures of micro-joints was analyzed.The results indicate that the formation of intermetallic compound Ag3Sn is the key factor to affect the shear force and the fine eutectic network structures of micro-joints as well as the dispersion morphology of fine compound Ag3Sn,in which eutectic network band is responsible for the improvement of the shear force of micro-joints soldered with Sn-Ag-Cu lead-free solder.With the increases of output power of diode-laser,the shear force and the microstructures change obviously.The eutectic network structures of micro-joints soldered with diode-laser soldering method are more homogeneous and the grains of Ag3Sn compounds are finer in the range of near optimal output power than those soldered with IR reflow soldering method,so the shear force is also higher than that using IR reflow soldering method.When the output power value of diode-laser is about 41.0 W,the shear force exhibits the highest value that is 70% higher than that using IR reflow soldering method. 展开更多
关键词 DIODE-LASER SOLDERING SN-AG-CU lead-free SOLDER shear force microstructure
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Ultrasensitive and stable X-ray detection using zero-dimensional lead-free perovskites 被引量:13
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作者 Xiaojia Zheng Wei Zhao +7 位作者 Peng Wang Hairen Tan Makhsud I.Saidaminov Shujie Tie Ligao Chen Yufei Peng Jidong Long Wen-HuZhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第10期299-306,共8页
Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of... Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors. 展开更多
关键词 X-ray detector Zero-dimensional perovskite lead-free Carrier concentration STABILITY Limit of detection Sensitivity
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Formation of Bulk Intermetallic Compound AgaSn in Slowly-Cooled Lead-Free Sn-4.0 wt pct Ag Solders 被引量:4
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作者 Jun SHEN+, Yongchang LIU, Yajing HAN, Peizhen ZHANG and Houxiu GAO College of Materials Science & Engineering, Tianjin University, Tianjin 300072, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第6期827-830,共4页
Sn-Ag alloy system has been regarded as one of the most promising lead-free solder to substitute conventional Sn- Pb eutectic solder. But the formation of bulk Ag3Sn intermetallic compounds (IMCs) during reflow and ... Sn-Ag alloy system has been regarded as one of the most promising lead-free solder to substitute conventional Sn- Pb eutectic solder. But the formation of bulk Ag3Sn intermetallic compounds (IMCs) during reflow and post heat treatment significantly influences the performance of the solder joints. With an effort to clarify its microstructural evolution as a function of slow cooling rates, the fraction of bulk IMCs within the slowly solidified Sn-4.0 wt pct Ag solder was investigated by standard metallographic and compared with that detected by thermal analysis. It was found that the bulk IMCs fraction determined by thermal analysis corresponds quite well with the microstructure observation results. In accordance with the conventional solidification theory, the lower the applied cooling rate, the fewer the amount of bulk Ag3Sn IMCs formed in Sn-4.0 wt pct Ag alloy. In addition, Vickers hardness measurement results indicated that the relative coarse eutectic Ag3Sn IMCs distributing in the lamellar eutectic structure favored the improvement of the mechanical performance. 展开更多
关键词 lead-free solder Intermetallic compounds Microstructure Thermal analysis
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Effects of Ga,Al,Ag,and Ce multi-additions on the wetting characteristics of Sn-9Zn lead-free solder 被引量:3
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作者 WANG Hui XUE Songbai +1 位作者 ZHAO Feng CHEN Wenxue 《Rare Metals》 SCIE EI CAS CSCD 2009年第6期600-605,共6页
An orthogonal method was used to evaluate the effects of Ga, Al, Ag, and Ce multi-additions on the wetting characteristics of Sn-9Zn lead-free solders by wetting balance method. The results show that the optimal loadi... An orthogonal method was used to evaluate the effects of Ga, Al, Ag, and Ce multi-additions on the wetting characteristics of Sn-9Zn lead-free solders by wetting balance method. The results show that the optimal loading of Ga, Al, Ag, and Ce was 0.2 wt.%, 0.002 wt.%, 0.25 wt.%, and 0.15 wt.%, respectively. Intermetallic compounds (IMCs) formed at the interface between Sn-9Zn-0.2Ga-0.002Al-0.25Ag- 0.15Ce solder and Cu substrate were investigated by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analysis. The SEM images illustrate that the IMCs can be divided into two portions from the substrate side to the solder side: a planar CusZns layer and an additional continuous scallop-like AgZn3 layer. The EDS analysis also shows that Ga segregates in the solder abutting upon the interface. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) of the surface components of Sn-9Zn-0.2Ga-0.002Al- 0.25Ag-0.15Ce solder indicate that Al aggregates at the surface in the form of Al203 protective fdm, which prevents the further oxidation of the solder surface. On the other hand, Ce aggregates at the subsurface, which may reduce the surface tension of the solder and improve the wettability in consequence. 展开更多
关键词 METALLOGRAPHY lead-free solder wetting balance method WETTABILITY intermetallic compounds
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Research progress in lead-less or lead-free three-dimensional perovskite absorber materials for solar cells 被引量:4
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作者 Huan-yu Zhang Rui Li +2 位作者 Wen-wu Liu Mei Zhang Min Guo 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2019年第4期387-403,共17页
The trend toward lead-free or lead-less perovskite solar cells(PSCs) has attracted increasing attention over the past few years because the toxicity of lead(Pb) is one of the substantial restrictions for large-scale a... The trend toward lead-free or lead-less perovskite solar cells(PSCs) has attracted increasing attention over the past few years because the toxicity of lead(Pb) is one of the substantial restrictions for large-scale applications. Researchers have investigated the viability of substituting Pb with other elements(group 14 elements, group 2 elements, transition-metal elements, and group 13 and 15 elements) in the three-dimensional(3 D) perovskites by theoretical calculations and experimental explorations. In this paper, recent research progress in Pb-less and Pb-free PSCs on the perovskite compositions, deposition methods, and device structures are summarized and the main problems that hinder the enhancement of device efficiency and stability are discussed in detail. To date, the fully Sn-based PSCs have shown a power conversion efficiency(PCE) of 8.12% and poor device stability. However, lead-less PSCs have shown higher PCE and a better stability. In addition, the introduction of double-perovskite materials also draws researchers' attention. We believe that the engineering of elemental composition, perovskite deposition methods, and interfacial modification are critical for the future development of Pb-less and Pb-free PSCs. 展开更多
关键词 PEROVSKITE solar cells lead-free PEROVSKITE MATERIALS lead-less PEROVSKITE MATERIALS composition engineering stability
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Property alterations of Sn-0.6Cu-0.05Ni-Ge lead-free solder by Ag, Bi, In and Sb addition 被引量:3
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作者 Kannachai KANLAYASIRI Rachata KONGCHAYASUKAWAT 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第6期1166-1175,共10页
The Sn-Cu-Ni-Ge solder is a strong challenger to the Sn-Ag-Cu(SAC) solders as a replacement for the Sn-Pb eutectic solder. This research investigated the effects of addition of Ag, Bi, In, and Sb on the physical pro... The Sn-Cu-Ni-Ge solder is a strong challenger to the Sn-Ag-Cu(SAC) solders as a replacement for the Sn-Pb eutectic solder. This research investigated the effects of addition of Ag, Bi, In, and Sb on the physical properties of the Sn-0.6 Cu-0.05 Ni-Ge(SCNG) lead-free solder and the interfacial reaction with the Cu substrate. The melting behavior, microstructure, tensile strength, and wettability of the SCNG-x(x=Ag, Bi, In, Sb) solders were examined. The findings revealed that the introduction of Ag, Bi, In, and Sb minimally altered the solidus temperature, liquidus temperature, and tensile strength of the solder. However, the cooling behavior and solidified microstructure of the solder were affected by the concentration of the alloying elements. The wettability of the SCNG solder was improved with the doping of the alloying elements except Sb. The thickness of intermetallic layer was increased by the addition of the alloying elements and was related to the cooling behavior of the solder. The morphology of intermetallic layer between the SCNG-x solders and the Cu substrate was different from that of the typical SAC solders. In conclusion, alloying the SCNG solder with Ag, Bi, In or Sb is able to improve particular properties of the solder. 展开更多
关键词 Sn-Cu-Ni-Ge solder lead-free solder alloying effect physical properties
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Manufacture and Cytotoxicity of a Lead-free Piezoelectric Ceramic as a Bone Substitute—Consolidation of Porous Lithium Sodium Potassium Niobate by Cold Isostatic Pressing 被引量:3
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作者 Qi Wang Jun Yang +4 位作者 Wu Zhang Roxanne Khoie Yi-ming Li Jian-guo Zhu Zhi-qing Chen 《International Journal of Oral Science》 SCIE CAS CSCD 2009年第2期99-104,共6页
Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing (CIP) was applied to fabricate... Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing (CIP) was applied to fabricate porous lithium sodium potassium niobate (Li0.06Na0.5K0.44) NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague- Dawley rats were examined by a scanning electron microscopy (SEM) and metbylthiazol tetrazolium (MTT) assay. Results The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. Conclusion Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute. 展开更多
关键词 lead-free piezoelectric ceramic cold isostatic pressing (CIP) CYTOCOMPATIBILITY OSTEOBLAST
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Influence of Cu content on microstructure,grain orientation and mechanical properties of Sn-xCu lead-free solders 被引量:3
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作者 Kannachai KANLAYASIRI Niwat MOOKAM 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第4期1226-1241,共16页
The effect of Cu content on the microstructure,grain orientation and mechanical properties of Sn-xCu(x=0-4.0 wt.%)lead-free solder was studied.Results showed that added Cu induced the formation of intermetallic phases... The effect of Cu content on the microstructure,grain orientation and mechanical properties of Sn-xCu(x=0-4.0 wt.%)lead-free solder was studied.Results showed that added Cu induced the formation of intermetallic phases.Only theη-Cu;Sn;andε-Cu;Sn phases were present in theβ-Sn matrix.For all contents,the strongly preferred orientation of theβ-Sn phase was formed on the{001}plane.In Sn doped with 1.0 wt.%Cu,theη-Cu;Sn;phase exhibited the preferred orientation of{0001}plane,whereas doping with 3.0 or 4.0 wt.%Cu transformed the preferred orientation to the{010}plane.In addition,only the{0001}and{■}planes were present in theε-Cu;Sn phase.The high Cu contents contributed to an increased number of low-angle boundaries,high residual strain,tensile strength and microhardness. 展开更多
关键词 lead-free solder Sn-Cu alloys crystallographic orientation MICROSTRUCTURE INTERMETALLICS mechanical properties
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