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Corrosion resistance of in-situ growth of nano-sized Mg(OH)2 on micro-arc oxidized magnesium alloy AZ31-Influence of EDTA
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作者 Chang-Yang Li Xiao-Li Fan +8 位作者 Rong-Chang Zeng Lan-Yue Cui Shuo-Qi Li Fen Zhang Qing-Kun He M. Bobby Kannan Hong-Wei (George) Jiang Dong-Chu Chen Shao-Kang Guan 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第6期1088-1098,共11页
One of the major obstacles for the clinical use of biodegradable magnesium(Mg)-based materials is their high corrosion rate. Micro-arc oxidation(MAO) coatings on Mg alloys provide mild corrosion protection owing to th... One of the major obstacles for the clinical use of biodegradable magnesium(Mg)-based materials is their high corrosion rate. Micro-arc oxidation(MAO) coatings on Mg alloys provide mild corrosion protection owing to their porous structure. Hence, in this study a dense Mg(OH)2 film was fabricated on MAO-coated Mg alloy AZ31 in an alkaline electrolyte containing ethylenediamine tetraacetic acid disodium(EDTA-2 Na) to reinforce the protection. Surface morphology, chemical composition and growth process of the MAO/Mg(OH)2 hybrid coating were examined using field-emission scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectrophotometer. Corrosion resistance of the coatings was evaluated via potentiodynamic polarization curves and hydrogen evolution tests. Results manifested that the Mg(OH)2 coating possesses a porous nano-sized structure and completely seals the micro-pores and micro-cracks of the MAO coating.The intermetallic compound of AlMn phase in the substrate plays a key role in the growth of Mg(OH)2 film. The current density of Mg(OH)2-MAO composite coating decreases three orders of magnitude in comparison with that of bare substrate, indicating excellent corrosion resistance. The Mg(OH)2-MAO composite coating is beneficial to the formation of calcium phosphate corrosion products on the surface of Mg alloy AZ31, demonstrating a great promise for orthopaedic applications. 展开更多
关键词 MAGNESIUM alloys Micro-arc oxidation MAGNESIUM HYDROXIDE Coatings BIOMATERIALS
镁及镁合金行业标准体系不断完善相关标准研制井喷可期 预览
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作者 席欢 《世界有色金属》 2019年第2期161-165,共5页
镁及镁合金广泛应用于汽车、3C产品、轨道交通、城市建设、医疗和军工等行业。SAC/TC243经过2018年12月对镁及镁合金行业2个月的研究工作,准备在镁及镁合金领域制定更多的系列标准,使镁及镁合金领域的标准体系能够完善和适应行业需要。
关键词 镁合金 标准 国际标准
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固态和液态镁及镁锂合金的密度 预览
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作者 R.N.ABDULLAEV R.A.KHAIRULIN +2 位作者 Yu.M.KOZLOVSKII A.Sh.AGAZHANOV S.V.STANKUS 《中国有色金属学报:英文版》 SCIE EI CAS CSCD 2019年第3期507-514,共8页
给出关于固体和液态的镁以及含23.03at.%和30.02at.%Li的超轻镁锂合金的密度和热膨胀率的新实验数据。采用膨胀计法和伽马射线衰减技术进行测量,测量的温度范围对于镁为145~1244K,对于镁锂合金为293~1000K。直接测量Mg和Mg70Li30合金在... 给出关于固体和液态的镁以及含23.03at.%和30.02at.%Li的超轻镁锂合金的密度和热膨胀率的新实验数据。采用膨胀计法和伽马射线衰减技术进行测量,测量的温度范围对于镁为145~1244K,对于镁锂合金为293~1000K。直接测量Mg和Mg70Li30合金在固.液相变时的密度变化,建立体积性质与温度的关系和参考表。将所得结果与文献数据进行比较,结果表明,镁锂体系中的共晶成分不是23at.%Li。研究发现,在0~30at.%Li范围内,液态镁锂体系的摩尔体积与浓度几乎呈线性关系,和理想混合物的明显不同。 展开更多
关键词 密度 熔体 固体 镁锂合金 热膨胀 互扩散
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改善镁/氢化镁水解放氢性能研究进展 预览
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作者 杨波 邹建新 +1 位作者 曾小勤 丁文江 《有色金属工程》 CAS 北大核心 2019年第9期10-16,共7页
概述了Mg/MgH2水解产氢过程中遇到的问题,以及提高水解反应动力学的方法:一是增大Mg/MgH2的比表面积,二是打破水解过程中产生的Mg(OH)2保护层对水解的限制。总结了目前改善水解性的方法,如通过降低粉末尺寸、在溶液中添加不同催化剂(酸... 概述了Mg/MgH2水解产氢过程中遇到的问题,以及提高水解反应动力学的方法:一是增大Mg/MgH2的比表面积,二是打破水解过程中产生的Mg(OH)2保护层对水解的限制。总结了目前改善水解性的方法,如通过降低粉末尺寸、在溶液中添加不同催化剂(酸、盐等)和复合具有催化作用的第二相(金属氧化物、氯化物、金属氢化物、金属、石墨等)等。重点阐述了各催化剂对Mg/MgH2水解性能的影响及作用机理,并提出了一些建议与看法。 展开更多
关键词 氢化镁 水解 催化 氢气
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Corrosion resistance of nanostructured magnesium hydroxide coating on magnesium alloy AZ31: influence of EDTA
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作者 Xiao-Li Fan Yuan-Fang Huo +5 位作者 Chang-Yang Li M.Bobby Kannan Xiao-Bo Chen Shao-Kang Guan Rong-Chang Zeng Quan-Li Ma 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第6期520-531,共12页
A hexagonal nanosheet Mg(OH)2 coating was prepared through a one-step hydrothermal method using LiOH solution as mineralizer and then modified by ethylenediaminetetraacetic acid(EDTA) to minimize the rapid corrosion o... A hexagonal nanosheet Mg(OH)2 coating was prepared through a one-step hydrothermal method using LiOH solution as mineralizer and then modified by ethylenediaminetetraacetic acid(EDTA) to minimize the rapid corrosion of AZ31 Mg alloy.The performance of the coating was evaluated using electrochemical technique,hydrogen evolution measurements, nanoscratch test,Fourier-transform infrared spectroscopy(FTIR), X-ray diffraction(XRD) patterns and field-emission scanning electron microscopy(FESEM).The results suggested that the corrosion rate of bare AZ31 Mg alloys was significantly reduced by one and two orders of magnitude through the protection from Mg(OH)2 coating and modification with EDTA(i.e., EDTA-Mg(OH)2 coating), respectively.FESEM micrographs indicated that the modification in EDTA elicits to the formation of an EDTA-Mg(OH)2 composite with a thickness as twice as that of as-prepared Mg(OH)2 coating.Nanoscratch tests revealed strong adhesion between the composite or Mg(OH)2 coating and the substrate.The study of formation and corrosion mechanisms of the coatings manifested that Mg(OH)2 was first formed near the intermetallic compound AlMn particles and gradually covered the entire surface, wherein the AlMn particles played an important role in the coating growth process.And it also proved that EDTA accelerated the formation of Mg(OH)2. 展开更多
关键词 Corrosion resistance MAGNESIUM alloy MAGNESIUM HYDROXIDE EDTA INTERMETALLIC compound
抑制蒸腾对番茄生长及植株镁、钾、钙吸收的影响 预览
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作者 李惠霞 刘岩 +1 位作者 陈竹君 周建斌 《干旱地区农业研究》 CSCD 北大核心 2019年第4期111-116,共6页
北方日光温室生产中蔬菜频繁出现营养失调,导致产量、品质明显下降,为探明番茄养分失调是否与蒸腾受到抑制有关,通过2个水培试验分别研究了短期(24 h)及长期(24 d)喷施蒸腾抑制剂对中杂9号和改良毛粉两个番茄品种蒸腾、生物量和镁、钾... 北方日光温室生产中蔬菜频繁出现营养失调,导致产量、品质明显下降,为探明番茄养分失调是否与蒸腾受到抑制有关,通过2个水培试验分别研究了短期(24 h)及长期(24 d)喷施蒸腾抑制剂对中杂9号和改良毛粉两个番茄品种蒸腾、生物量和镁、钾及钙养分吸收的影响。结果表明:短期(24 h)抑制蒸腾,蒸腾量减少20.6%、镁吸收量减少4.5%,蒸腾与番茄镁吸收呈显著正相关关系;长期(24 d)喷施蒸腾抑制剂减少了番茄生长量、光合速率,蒸腾量减少47.5%时镁吸收量减少17.1%,钾、钙吸收量分别减少12.9%和44.1%,不同番茄品种间对钾、钙、镁的吸收无显著差异。可见,抑制蒸腾减少番茄对镁、钾、钙的吸收。北方日光温室冬茬栽培中高湿、寡照等不良环境因子会诱导番茄营养失调症的发生。 展开更多
关键词 抑制蒸腾 番茄 吸收 生长
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血镁水平与维持性血液透析患者全因死亡的相关性
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作者 田茂露 佟小雅 +2 位作者 林鑫 袁静 查艳 《中华肾脏病杂志》 CAS CSCD 北大核心 2019年第8期575-581,共7页
目的探讨血液透析患者血镁(Mg)水平与全因死亡的相关性.方法纳入2015年6月至2016年6月于贵州省7家血液透析中心行维持性血液透析(MHD)治疗3个月以上的门诊成人患者.收集并记录患者人口学资料、稳定透析3个月以上且第一年随访时的临床及... 目的探讨血液透析患者血镁(Mg)水平与全因死亡的相关性.方法纳入2015年6月至2016年6月于贵州省7家血液透析中心行维持性血液透析(MHD)治疗3个月以上的门诊成人患者.收集并记录患者人口学资料、稳定透析3个月以上且第一年随访时的临床及实验室检查作为基线数据.所有患者随访至2018年6月30日.根据患者基线血Mg水平四分位数将所有患者分为4组.采用Kaplan-Meier法比较各组患者生存率.采用Cox回归模型分析Mg与全因死亡的相关性.采用Logistic回归分析低血镁水平的影响因素.结果共868例具有基线Mg数据的血液透析患者被纳入研究,年龄(55.47±16.17)岁,其中男性516例(59.4%);低镁血症(Mg<0.7 mmol/L)患者11例(1.3%),高镁血症(Mg>1.05 mmol/L)患者432例(49.8%),Mg>2.0 mmol/L患者16例(1.8%).Mg水平中位数(四分位数间距)为1.05(0.95,1.24)mmol/L.Mg四分位数组间比较显示,4组间年龄、血红蛋白、血清白蛋白、血钙、甲状旁腺素(PTH)、血肌酐、血尿酸和血尿素氮水平差异均有统计学意义(均P<0.05).经过中位24个月的随访,207例患者死亡.Kaplan-Meier生存曲线显示基线血Mg≤0.95 mmol/L患者全因死亡率较高(Log-rank检验χ^2=15.11,P=0.002).但经年龄、合并症及生化指标(尤其是白蛋白)等校正后,4组患者全因死亡的风险比差异无统计学意义.多因素Logistic回归分析结果显示,低血清白蛋白(OR=0.946,95%CI 0.913~0.979,P=0.002)及低血尿酸(OR=0.994,95%CI 0.992~0.997,P<0.001)是基线血Mg≤0.95 mmol/L发生的危险因素.结论MHD患者中低镁血症少见,而高镁血症较常见.血Mg≤0.95 mmol/L与MHD患者全因死亡风险增加相关,但可能并非其独立危险因素.基线血清Mg≤0.95 mmol/L的发生与较低的血清白蛋白及血尿酸水平有关. 展开更多
关键词 肾透析 死亡率 危险因素
Recent Research on the Deformation Behavior of Particle Reinforced Magnesium Matrix Composite: A Review
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作者 Kun-Kun Deng Cui-Ju Wang +1 位作者 Kai-Bo Nie Xiao-Jun Wang 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第4期413-425,共13页
Particle reinforced magnesium matrix composite(PMMC) possesses the merits of high specific strength, high specific modulus, better dimensional stability, good wear resistance and lower production cost, which is though... Particle reinforced magnesium matrix composite(PMMC) possesses the merits of high specific strength, high specific modulus, better dimensional stability, good wear resistance and lower production cost, which is thought as a promising material in the field of aerospace, automobile, electronic communication, etc. To eliminate the casting defect, the PMMC is usually experienced hot deformation process. The present paper mainly focuses on the deformation behavior of PMMCs. First, the development of PMMCs based on particle size is introduced. Then, the hot deformation technology and deformation mechanism of PMMCs at elevated temperature are given and analyzed, respectively. After reviewing the dynamic recrystallization and texture of PMMCs, its future development is suggested based on the current research progress. 展开更多
关键词 MAGNESIUM matrix composite PARTICLE Hot DEFORMATION DEFORMATION mechanism RECRYSTALLIZATION
Effect of Different Scale Precipitates on Corrosion Behavior of Mg–10Gd–3Y–0.4Zr Alloy
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作者 Shuang Yu Rui-Ling Jia +3 位作者 Tao Zhang Fu-Hui Wang Jian Hou Hui-Xia Zhang 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第4期433-442,共10页
A large amount of directional and willow-like β’ phase was precipitated in Mg-10 Gd-3 Y-0.4 Zr(GW103 K) alloy after solution treatment and subsequently aged treatment(T6). In order to explore the effect of the preci... A large amount of directional and willow-like β’ phase was precipitated in Mg-10 Gd-3 Y-0.4 Zr(GW103 K) alloy after solution treatment and subsequently aged treatment(T6). In order to explore the effect of the precipitates on the corrosion behavior of the GW103 K alloy, the alloy was subjected to solution treatment(T4) at 773 K for 4 h at first, subsequently aged at 498 K for 193 h(T6). The microstructure evolution of the GW103 K alloy after this treatment was investigated by scanning electron microscopy and transmission electron microscopy. The high-angle annular detector dark-field scanning transmission electron microscopy was used to observe the typical corrosion morphologies of the nanoscale precipitation phases(β’) in the T6-treated alloy. The corrosion rate was measured by potentiodynamic polarization test. Combining with the potential measurement results by scanning Kelvin probe force microscopy, the effects of the skeleton-like Mg24(Gd,Y)5 andf precipitates on the corrosion behavior of GW103 K alloy were explored. The results showed that the corrosion rate of the GW103 K alloy in different conditions was ranked as: as-cast alloy> T4-treated alloy> T6-treated alloy,attributing to the fact that the relative potential differences of skeleton-like Mg24(Gd,Y)5 were lower than those of the matrix, therefore Mg24(Gd, Y)5 phase formed micro-galvanic coupling with the matrix and corrosion dissolution occurred.The nanoscale β’ precipitates in T6-treated alloy can retard the cathodic process. 展开更多
关键词 MAGNESIUM ALLOY AGING PRECIPITATES Corrosion Potential difference Transmission electron microscopy(TEM)
Effects of samarium content on microstructure and mechanical properties of Mg-0.5Zn-0.5Zr alloy
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作者 Kai Guan Fanzhi Meng +8 位作者 Pengfei Qin Qiang Yang Dongdong Zhang Baishun Li Wei Sun Shuhui Lv Yuanding Huang Norbert Hort Jian Meng 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第7期1368-1377,共10页
Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate th... Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate that grains of the as-cast alloys are gradually refined as Sm content increases. The dominant intermetallic ph^se changes from Mg3Sm to Mg4iSm5 till Sm content exceeds 5.0 wt%. The dynami-cally precipitated intermetallic phase during hot-extrusion in dll Sm-containing alloys is Mg3Sm. The intermetallic particles induced by Sm addition could act as heterogeneous nucleation sites for dynamic recrystallization during hot extrusion. They promoted dynamic recrystallization via the particle stim-ulated nucleation mechanism, and resulted in weakening the basal texture in the as-extruded alloys. Sm addition can significantly enhance the strength of the as-extruded Mg-0.5Zn-0.5Zr alloy at room temperature, with the optimal dosage of 3.5 wt%. The optimal yield strength (YS) and ultimate tensile strength (UTS) are 368 MPa and 383 MPa, which were enhanced by approximately 23.1% and 20.8% com-pared with the Sm-free alloy, respectively. Based on microstructural analysis, the dominant strengthening mechanisms are revealed to be grain boundary strengthening and dispersion strengthening. 展开更多
关键词 MAGNESIUM ALLOYS SAMARIUM Transmission electron MICROSCOPY (TEM) Microstructure Mechanical properties
Catalytic effect of SrTiO3 on the hydrogen storage behaviour of MgH2 预览
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作者 M.S.Yahya M.Ismail 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第1期46-53,共8页
The effects of Sr TiO3 on the hydrogen storage properties of MgH2 have been studied for the first time.The onset dehydrogenation temperature of the MgH2-10 wt% SrTiO3 is found to be 275℃, which is 55℃ lower as compa... The effects of Sr TiO3 on the hydrogen storage properties of MgH2 have been studied for the first time.The onset dehydrogenation temperature of the MgH2-10 wt% SrTiO3 is found to be 275℃, which is 55℃ lower as compared to the as-milled MgH2. The composite is able to absorb 4.3 wt% of hydrogen in 60 min instead of 1.1 wt% for the as-milled Mg H2. Meanwhile, the composite is able to release 5.3 wt% of hydrogen in 17 min compared to 1.9 wt% by the as-milled Mg H2 at 320℃. The calculated Eaof the Mg H2-10 wt% SrTiO3 is 109 k J/mol, which is 26.3 kJ/mol lower than the calculated Eaof the as-milled MgH2. The Sr TiO3 is not decomposed during the ball milling and the re/dehydrogenation processes. The catalytic effect shown by the SrTiO3 is owing to its ability to change the physical structure of the MgH2 particles during the ball milling process. 展开更多
关键词 Hydrogen storage MAGNESIUM HYDRIDE CATALYTIC effect SORPTION properties
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Influence of Reaction Time on Growth Behaviours of Mg-Al LDH Films 预览
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作者 WU Liang CHEN Jing +5 位作者 ZHANG Sheng TANG Ai-tao YANG Dan-ni ZHANG Gen LIU Lei PAN Fu-sheng 《表面技术》 EI CAS CSCD 北大核心 2019年第3期19-26,共8页
Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method.The characteristics of the film were investigated by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),scanning electron m... Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method.The characteristics of the film were investigated by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),scanning electron microscopy(SEM)observation and electrochemical tests.The results showed that the crystallinity of LDH film was increased with reaction time.When the reaction time was more than 12 h,the LDH film had complete crystal layered structure.The anodic oxide film was sealed basically by the growth of LDH nanosheets after 6 h reaction.The corrosion resistance of the films became better with the increasing of reaction time.However,after 12 h reaction,the corrosion resistance of the film decreased.The formation behavior of the Mg-Al LDH film was proposed.That the competitive growth of LDH grains,which contains dissolution and recrystallization,was proposed to explain the change of the growth and corrosion resistance of the Mg-Al LDH film. 展开更多
关键词 magnesium alloy corrosion resistance in-situ GROWTH LAYERED double hydroxide(LDH) reaction time
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Magnesium:pathophysiological mechanisms and potential therapeutic roles in intracerebral hemorrhage 预览
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作者 Jason J.Chang Rocco Armonda +1 位作者 Nitin Goyal Adam S.Arthur 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第7期1116-1121,共6页
Intracerebral hemorrhage(ICH)remains the second-most common form of stroke with high morbidity and mortality.ICH can be divided into two pathophysiological stages:an acute primary phase,including hematoma volume expan... Intracerebral hemorrhage(ICH)remains the second-most common form of stroke with high morbidity and mortality.ICH can be divided into two pathophysiological stages:an acute primary phase,including hematoma volume expansion,and a subacute secondary phase consisting of blood-brain barrier disruption and perihematomal edema expansion.To date,all major trials for ICH have targeted the primary phase with therapies designed to reduce hematoma expansion through blood pressure control,surgical evacuation,and hemostasis.However,none of these trials has resulted in improved clinical outcomes.Magnesium is a ubiquitous element that also plays roles in vasodilation,hemostasis,and blood-brain barrier preservation.Animal models have highlighted potential therapeutic roles for magnesium in neurological diseases specifically targeting these pathophysiological mechanisms.Retrospective studies have also demonstrated inverse associations between admission magnesium levels and hematoma volume,hematoma expansion,and clinical outcome in patients with ICH.These associations,coupled with the multifactorial role of magnesium that targets both primary and secondary phases of ICH,suggest that magnesium may be a viable target of study in future ICH studies. 展开更多
关键词 INTRACEREBRAL HEMORRHAGE stroke magnesium VASODILATION HEMOSTASIS blood-brain barrier perihematomal EDEMA
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基于叶绿素叶面分布特征的黄瓜氮镁元素亏缺快速诊断 预览
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作者 石吉勇 李文亭 +4 位作者 胡雪桃 黄晓玮 李志华 郭志明 邹小波 《农业工程学报》 EI CAS CSCD 北大核心 2019年第13期170-176,共7页
为了快速、无损诊断作物氮(N)、镁(Mg)营养亏缺,该研究提出一种以叶绿素叶面分布特征诊断黄瓜 N、Mg 元素亏缺的方法。在设施栽培模式下精确控制 N、Mg 营养元素的供给,培养黄瓜缺 N、缺 Mg 及对照植株(营养元素正常植株),然后采集对应... 为了快速、无损诊断作物氮(N)、镁(Mg)营养亏缺,该研究提出一种以叶绿素叶面分布特征诊断黄瓜 N、Mg 元素亏缺的方法。在设施栽培模式下精确控制 N、Mg 营养元素的供给,培养黄瓜缺 N、缺 Mg 及对照植株(营养元素正常植株),然后采集对应的高光谱图像并结合化学计量学方法快速、无损检测叶绿素分布。与对照组叶片叶绿素分布相比,缺 N 叶片的叶绿素含量在整个叶面区域偏低,缺 Mg 叶片叶绿素在叶脉之间区域含量偏低。鉴于此,提取叶绿素叶面分布特征(叶片所有像素点对应的叶绿素含量均值及标准差)对 N、Mg 营养元素亏缺进行诊断,对预测集 N、Mg元素亏缺正确诊断率达 90%。研究结果表明叶绿素叶面分布特征可作为一种黄瓜 N、Mg 元素亏缺诊断依据。 展开更多
关键词 叶绿素 光谱分析 模型 分布特征 黄瓜叶片 氮元素 镁元素 高光谱成像
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EDTA络合滴定法快速测定矿石中钙、镁 预览
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作者 韩晓 《中国无机分析化学》 CAS 2019年第2期54-57,共4页
试样用盐酸、硝酸、氢氟酸、高氯酸分解,在pH值为6~9时,经六次甲基四胺-铜试剂分离铁、铝、镍、钴、铅、锌、铜、镉、锰等干扰元素后,在pH=10的氨水和氯化铵缓冲溶液中,以酸性铬蓝K-萘酚绿B为指示剂,用EDTA络合滴定法测定钙镁合量;另在... 试样用盐酸、硝酸、氢氟酸、高氯酸分解,在pH值为6~9时,经六次甲基四胺-铜试剂分离铁、铝、镍、钴、铅、锌、铜、镉、锰等干扰元素后,在pH=10的氨水和氯化铵缓冲溶液中,以酸性铬蓝K-萘酚绿B为指示剂,用EDTA络合滴定法测定钙镁合量;另在氢氧化钾溶液中,用钙试剂为指示剂,以EDTA络合滴定法测定钙量,从而计算镁的含量。当样品钙高镁低或者镁高钙低时,低含量的镁量或钙量(<5%)可用电感耦合等离子体原子发射光谱(ICP-AES)法准确测定,使结果更准确。实验中对三个标准样品中的钙和镁进行多次测定,结果与认定值相符,相对标准偏差在0.69%~1.3%(n=7),加标回收率在99%~102%。方法实用性强,已经成功应用于各类矿石中钙镁的检测。 展开更多
关键词 容量法 ICP-AES 矿石
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Effects of small additions of Zn on the microstructure, mechanical properties and corrosion resistance of WE43B Mg alloys 预览
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作者 A.V. Koltygin V.E. Bazhenov +3 位作者 R.S. Khasenova A.A. Komissarov A.I. Bazlov V.A. Bautin 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第7期858-868,共11页
Zn is a commonly used alloying element for Mg alloys owing to its beneficial effects on mechanical properties. To improve the mechanical and corrosion properties of WE43B Mg alloys, the effects of 0–0.7wt% Zn additio... Zn is a commonly used alloying element for Mg alloys owing to its beneficial effects on mechanical properties. To improve the mechanical and corrosion properties of WE43B Mg alloys, the effects of 0–0.7wt% Zn addition on the microstructure and properties of sample alloys were investigated. Addition of Zn to as-cast WE43B alloy promoted the formation of the Mg12Nd phase;by contrast, after T6 heat treatment, the phase composition of WE43B alloys with and without Zn addition remained mostly the same. A long-period stacking ordered phase was predicted by CALPHAD calculation, but this phase was not observed in either the as-cast or heat-treated Zn-containing WE43B alloys. The optimum temperature and duration of T6 heat treatment were obtained using CALPHAD calculations and hardness measurements. Addition of Zn resulted in a slight reduction in the average grain size of the as-cast and T6 heat-treated WE43B alloys and endowed them with increased corrosion resistance with little effect on their mechanical properties. 展开更多
关键词 MAGNESIUM alloys corrosion resistance mechanical properties ZN ADDITION
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Effect of heat treatment on the microstructure and micromechanical properties of the rapidly solidified Mg61.7Zn34Gd4.3 alloy containing icosahedral phase 预览
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作者 Wen-bo Luo Zhi-yong Xue Wei-min Mao 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第7期869-877,共9页
In this paper, the microstructure evolution of the rapidly solidified (RS) Mg61.7Zn34Gd4.3 (at%, atomic ratio) alloy at high temperatures was investigated. The hardness and elastic modulus of the main precipitated pha... In this paper, the microstructure evolution of the rapidly solidified (RS) Mg61.7Zn34Gd4.3 (at%, atomic ratio) alloy at high temperatures was investigated. The hardness and elastic modulus of the main precipitated phases were also analyzed and compared with those of the α-Mg matrix on the basis of nanoindentation tests. The results show that the RS alloy consists of either a petal-like icosahedral quasicrystal (IQC) phase (~20 μm) and block-shaped H1 phase (~15 μm) or IQC particles with an average grain size of ~107 nm as well as a small proportion of amorphous phase, which mainly depends on the holding time at the liquid temperature and the thickness of the ribbons. The IQC phase gradually transforms at 400?C to a short-rod-shaped μ-phase (Mg28.6Zn63.8Gd7.7) with a hexagonal structure. The hardness of the IQC phase is higher than that of H1 phase, and both phases exhibit a higher hardness than the α-Mg matrix and the μ-phase. The elasticity of the H1 phase is superior to that of the α-Mg matrix. The IQC phase possesses a higher elastic modulus than H1 phase. The easily formed H1 phase exhibits the poorest plastic deformation capacity among these phases but a higher elastic modulus than the α-Mg matrix. 展开更多
关键词 magnesium ALLOY ICOSAHEDRAL phase rapidly SOLIDIFICATION NANOINDENTATION MICROMECHANICAL properties
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A High-Ductility Mg–Zn–Ca Magnesium Alloy
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作者 Teng Tu Xian-Hua Chen +2 位作者 Jiao Chen Chao-Yue Zhao Fu-Sheng Pan 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第1期23-30,共8页
A new kind of Mg–2 Zn–0.6 Ca(wt%) alloy was fabricated by casting and hot extrusion as a high-ductility structural material. The extruded alloy exhibits a superior elongation of ~30%, yield strength of 130 MPa and u... A new kind of Mg–2 Zn–0.6 Ca(wt%) alloy was fabricated by casting and hot extrusion as a high-ductility structural material. The extruded alloy exhibits a superior elongation of ~30%, yield strength of 130 MPa and ultimate tensile strength of 280 MPa along the extrusion direction at room temperature. Microstructure, texture and tensile properties of the extruded alloy were investigated in details. The remarkable improvement of ductility is ascribed to the weakened basal texture, refined grains and a small number of second phase in the alloy. 展开更多
关键词 Magnesium alloy Mg–Zn–Ca High DUCTILITY EXTRUSION TEXTURE
Strength and Wear Behavior of Mg Alloy AE42 Reinforced with Carbon Short Fibers
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作者 Sabbah Ataya Naser A.Alsaleh Mohamed M.El-Sayed Seleman 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第1期31-40,共10页
In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it n... In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it necessary to assess their wear performance. Little research data have been discussed on wear behavior of Mg alloy AE42 matrix and its composites. Thus, this paper reports wear behavior of magnesium alloy AE42(Mg–Al–Mn—RE;rare earth) and its composite AE42-C, which contains 23 vol% of randomly oriented carbon short fibers. Materials characterization, including density measurements, hardness testing, microstructures investigation, and compression testing at temperatures of 25, 150,and 300 °C, were conducted. Wear tests were performed under various loads and sliding distances. Wear mechanisms were also proposed based on the examination of worn surfaces using optical microscopy and scanning electron microscopy equipped with EDX(energy-dispersive X-ray spectrometry) analysis system. The hardness of AE42-23 vol% C composite is twice the hardness of the Mg matrix alloy AE42. Significant improvements to yield stress and compressive strength at temperatures of 25, 150, and 300 °C of the composite versus the AE42 alloy are achieved. Wear resistance of the composite is improved considerably versus that of the Mg alloy AE42 at the various sliding distances. Smearing of graphite on the worn surface produces a lubricating film that delays change from mild to severe wear of the composite, especially at high loads. EDX analysis of the worn surface shows oxidation of the matrix alloy at higher wear loads, and this mechanism decreases in the presence of carbon fibers under the same loads. Abrasive wear, oxidation, and plastic deformation are the dominant wear mechanisms for the alloy matrix AE42, whereas mainly abrasive wear is the wear mechanism of AE42-23 vol% C composite under the proposed testing conditions. 展开更多
关键词 Magnesium composites CARBON short fibers COMPRESSIVE STRENGTH WEAR resistance WEAR mechanisms
Feasibility of aluminum recovery and MgAl2O4 spinel synthesis from secondary aluminum dross 预览
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作者 Yong Zhang Zhao-hui Guo +2 位作者 Zi-yu Han Xi-yuan Xiao Chi Peng 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第3期309-318,共10页
The feasibility of aluminum recovery from secondary aluminum dross by extraction with NaOH solution and the subsequent synthesis of MgAl2O4 spinel by sintering the extracted slag were studied. The extraction percentag... The feasibility of aluminum recovery from secondary aluminum dross by extraction with NaOH solution and the subsequent synthesis of MgAl2O4 spinel by sintering the extracted slag were studied. The extraction percentage of soluble aluminum from the dross reached 80% at a temperature of 353 K, liquid-to-solid ratio of 12 mL·g^-1, stirring speed of 300 r·min^-1, and an extraction time of 15 min;the hydrolysis percentage of AlN reached 40% with an extraction time of 30 min. The activation energies of the soluble aluminum and AlN extracted from the dross were 7.15 and 8.98 kJ·mol^-1, respectively, indicating that their kinetics were controlled by outer diffusion without a product layer. The extracted slag was sintered in the temperature range 1373–1773 K;MgAl2O4 spinel with a compressive strength as high as 69.4 MPa was produced in the sample sintered at 1673 K for 3 h. This value exceeds the threshold (40 MPa) prescribed by the National Standard for the Magnesia and Magnesia-alumina Refractory Bricks of China (GB/T 2275?2007). These results establish the effectiveness of aluminum recovery from secondary aluminum dross and subsequent MgAl2O4 spinel synthesis. 展开更多
关键词 SECONDARY ALUMINUM DROSS reuse extraction sintering magnesium ALUMINATE SPINEL
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