Preparation of Gd-Co alloy film in acetamide-urea-NaBr melt

Electroreduction of Co(Ⅱ） to metallic Co in acetamide-urea-NaBr metl at 353K is irreversible in one step.Gd(Ⅲ） is not reduced to Gd alone,but can be inductively codeposited with Co(Ⅱ.The amorphous Gd-Co alloy films were obtained by potentiostatic electrolysis.With the cathode potential shifting to negative direction.the content of gadolinium in the alloy increases and can get to 65.89%(mass fraction).The additive of Na2EDTA can make the diameter of the particles of crystalline alloy smaller and change the shape of particles.     

Preparation of Y-Co alloy film in acetamide-urea-NaBr melt

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｒａｒｅｅａｒｔｈ ｃｏｂａｌｔａｌｌｏｙｓｈａｖｅｍａｎｙｓｐｅｃｉａｌｐｒｏｐｅｒｔｉｅｓａｎｄｃａｎｂｅｕｓｅｄｔｏｐｒｅｐａｒｅｍａｇｎｅｔｉｃａｎｄｍａｇ ｎｅｔｏ ｏｐｔｉｃａｌｃｏｍｐｏｎｅｎｔｓ.Ｓｏｆａｒ,ｒａｒｅｅａｒｔｈａｌｌｏｙｆｉｌｍｓｈａｖｅｕｓｕａｌｌｙｂｅｅｎｐｒｏｄｕｃｅｄｂｙｓｐｕｔｔｅｒｉｎｇｏｒｖａｃｕｕｍｐｌａｔｉｎｇ .Ｉｆｓｕｃｈｔｈｉｎｆｉｌｍｓｗｅｒｅｐｒｅｐａｒｅｄｂｙｅｌｅｃｔｒｏｄｅｐｏ ｓｉｔｉｏｎ,ｔｈｅｐｒｏｄ…     

Preparation of Gd-Ni alloy film in urea-NaBr melt

1　ＩＮＴＲＯＤＵＣＴＩＯＮＧｄｉｎ 4ｆｌａｎｔｈａｎｏｉｄｈａｓｆｅｒｒｏｍａｇｎｅｔｉｃ ｐａｒａｍａｇ ｎｅｔｉｓｍｔｒａｎｓｆｏｒｍｔｅｍｐｅｒａｔｕｒｅ (Ｃｕｒｉｅｐｏｉｎｔ) ,ａｎｄｔｈｅｈｉｇｈｅｓｔｍａｇｎｅｔｉｃｔｈｅｒｍａｌｅｎｔｒｏｐｙｃｈａｎｇｅｓａｔｒｏｏｍｔｅｍｐｅｒａｔｕｒｅ .Ｓｏｆａｒ ,ｉｔｉｓｓｔｉｌｌｔｈｅｂｅｓｔｍａｇｎｅｔｉｃｒｅ ｆｒｉｇｅｒａｔｉｏｎｗｏｒｋｉｎｇｓｕｂｓｔａｎｃｅｍａｔｅｒｉａｌａｔｒｏｏｍｔｅｍ ｐｅｒａｔｕｒｅ .Ｎｏｗｒａｒｅｅａｒｔｈ…     

Preparation and characterization of La-Co alloy nanowire arrays by electrodeposition in AAO template under nonaqueous system

La-Co alloy nanowires can be made in pulse reversal current（PRC） and direct current（DC） electrodepositions under nonaqueous system, with the porous anodic aluminum oxide（AAO） as template. This membrane is subject to the dual-oxidation （two-step） anodizing. Scanning electron microscope（SEM） examination shows that all of the nanowires have uniform diameter about 200 nm, and their diameters are determined by the pore diameter of applied AAO template. X-ray energy dispersion analysis indicates that the chemical composition of La and Co elements is very close to 1：2 in stoichiometry. X-ray diffraction pattern investigation demonstrates that La-Co nanowire is the face-centered cubic（FCC） LaCo13.     

Influence of additive element on surface oxide film ofA356 alloy

The influences of RE-modification and Sr-modification on the hydrogen content and surface oxide film ofA356 aluminum alloy melt were investigated. The hydrogen content of the melt was measured by reduce pressure test. The phases in the surface oxide film were analyzed by X-ray diffractometry （XRD）, and the morphology of the surface oxide film was observed by scanning electronic microscopy （SEM）. The results show that RE-modification reduces the hydrogen content ofA356 aluminum alloy greatly. Contrarily, Sr-modification increases the hydrogen content remarkably. After being treated with RE, a large number of LaAl11O18 consisting of Al2O3 and La2O3, are generated in the surface oxide film of A356 alloy. The surface oxide film of Sr-modification is almost composed of Al2SrO4. According to the results of SEM, the surface oxide film of Sr-modification is very easy to crack, destroy the continuity and compactness of surface oxide film, accelerate the vapor diffusing into the melt, consequently, increase the hydrogen content of A356 alloy melt significantly. But RE-modification makes the surface oxide film compact, and restrains the aluminum exposed to water, so reduces the hydrogen content ofA356 alloy melt.     

钇对锂铝合金阳极性能的影响

研究了稀土元素钇对锂铝合金阳极充放电性能及其表面结构的影响。在锂铝合金阳极中添加０．５％～１．５％钇,电池的放民容量和放电电压分别提高了１０ｍＡｈ、５０ｍＶ。添加钇的锂铝合金阳极经过３次充放电后,电极表面结构完整均匀。多孔型锂铝合是极比平板型锂铝合金阳极的放电容量有明显提高,添加０．５％～１．５％钇的多孔锂铝合金阳极具有理想的充放电性能。锂铝合金阳极的驻留和电过程受锂原子在电极中的扩散速度控制。     

Electrochemical investigation on the formations of Dy-Ni alloy films in dimethylformamide

The electrochemical properties of Dy(Ⅲ), Ni(Ⅱ) and Dy(Ⅲ) Ni(Ⅱ) in dimethylformamide were studied by cyclic voltammetry on Pt or Cu electrode. Black, metallic lustered, compact and well adhesive Dy-Ni alloy films can be co-deposited on Cu electrode by sweeping-potential-deposition method within some potentials. SEM, EDAX and XRD were used to analyze the alloy films. The Dy content in the Dy-Ni alloy film is up to 56.91%(mass fraction) and the DyNi alloy films are amorphous.     

Electrochemical mechanism of electrolysis codeposition of Mg-Sr alloy in molten salt

The electrochemical process of Mg-Sr codeposition was studied in MgCl₂-SrCl₂-KCl melts containing different MgCl₂ concentrations at 700 °C by cyclic voltammetry, chronopotentiometry and chronoamperometry. The results show that the actual precipitation potential of Sr reduces by nearly 0.5 V because of the depolarization effects of Sr activity reduced by forming Mg-Sr alloy. The codeposition potential condition of Mg and Sr to form Mg-Sr alloy is as follows: When electrode potential is more negative than ?1.5 V, the magnesium will precipitate; when electrode potential is more negative than ?2.0 V, the magnesium and strontium will both deposit. The control step of codeposition process of Mg and Sr is not diffusion control step. The codeposition current condition of Mg and Sr to form Mg-Sr alloy by chronoptentiometry is as follows: cathode current densities are higher than 0.71, 1.57 and 2.83 A/cm² in MgCl₂-SrCl₂-KCl melts with MgCl₂ concentrations of 2%, 5% and 10% (mass fraction), respectively.     

Reaction behavior between the oxide film of LY12 aluminum alloy and the flux

In this paper, the brazing mechanism of LY12 aluminum alloy at middle range temperature was presented. The CsF-AlF3 non-corrosive flux was utilized to remove the complex oxide film on the surface of LY12 aluminum alloy. The resultsrevealed that the oxide film was removed by the improved CsF-AlF3 flux accompanied with the occurrence of reaction as well as dissolution and the compounds CsF played an important role to remove the oxide film. Actually, the high activity of flux, say,the ability to remove the oxide film, was due to the presence of the compounds, such as NH4F,NH4AlF4 and composite molten salt. The production of HF was the key issue to accelerate the reaction and enhance to eliminate the oxide film by dissolution.It was found that the rare earth element La at small percentage was not enriched at the interface. Moreover, the rare earth fluoride enhanced the dissolution behavior.     

LY12铝合金氧化膜与钎剂的反应机制

采用CsF-AlF3中温无腐蚀钎剂能够去除LY12铝合金表面复杂的氧化膜, 实现LY12铝合金的中温钎焊.研究发现: 改进的CsF-AlF3钎剂是以反应、溶解方式去除氧化膜的; 在去膜过程中, CsF化合物起主要去膜作用, 钎剂的高活性与NH4F、NH4AlF4及复合盐熔体等化合物的存在有关, 它们的存在可提高CsF-AlF3钎剂的去膜能力, 而HF的生成则是诱发和加速反应、提高溶解去膜能力的关键;微量稀土元素镧未在界面出现富集现象,微量的稀土氟化物则起着"助溶"的作用.     

稀土合金表面室温熔盐电沉积铝的研究

以稀土合金为基体,探讨了在酸性的AlCl3-EMIC(2:1)室温熔盐中电沉积铝镀层的可能性,重点研究了稀土合金前处理工艺对镀层的影响。用SEM、EDS及XRD对电沉积前后的试样表面及界面进行了微观分析,用划格撕扯法对镀层与基体的结合力进行测定。结果表明,可以通过室温熔盐电沉积的方法,在稀土合金表面电沉积Al镀层;且对稀土合金表面在煤油中进行前处理,可防止稀土氧化膜的产生,并能得到均匀致密、结合良好的铝镀层;在电流密度2 A/dm2,沉积时间2500 s条件下,可得到颗粒大小约10 μm、厚度17 μm的纯铝层,电流效率接近100%。对稀土合金表面电沉积Al机制进行了讨论     

Electrochemical preparation of Er-Co-Bi thin film in organic bath by cyclic electrodeposition method

Cyclic electrodeposition was used to investigate the preparation of Er-Co-Bi alloy thin film in DMSO system. Experimental results indicate that Er-Co-Bi alloy thin film containing 14.83 %- 32.65% Er is prepared from 0.1 mol/L ErCl3 0. 1 mol/L CoCl2 0. 1 mol/L Bi (NO3)3 0. 1 mol/L LiCl DMSO system by cyclic electrodeposition on Cu substrate. The optimum cyclic potential of electrodeposition is that upper potential is within a potential range from -0.50 V to -1.00 V and lower potential is within a potential range from -2.00 V to -2.60 V.The surface of alloy thin film observed by scanning electron microscope is black, adhesive and has metallic luster.The film is amorphous proved by the X-ray diffractometry.     

Gd对AZ91D合金铸态组织及性能的影响

研究了稀土元素Gd对铸态AZ91D镁合金组织与性能的影响.试验结果表明,Gd元素对合金的组织有细化作用,加入了Gd元素后,合金中会形成Al2Gd相,适量添加Gd元素会提升合金的性能,当Gd的质量分数为1.0％时,合金的性能最好.     

稀土熔剂对Al-10%Pb合金组织和性能的影响

采用一种含有玻璃成分的稀土熔剂,在1 080℃高温条件下,对Al-10%Pb合金熔体进行覆盖、保护和净化.结果表明:同无熔剂相比,加入量为1.0%和0.5%时,合金的抗拉强度分别提高12.8%和12.0%,延伸率分别提高42.8%和6.5%;当流道厚度为1.0 mm时,合金的流动性分别提高27.3%和1.4%.同1.5%的熔剂加入量相比,采用1.0%的稀土熔剂处理后的Al-Pb合金组织中铅粒圆整,平均直径仅为20 μm左右,分布比较均匀.分析了该种熔剂的作用机理.     

Investigation on Preparation of Tb2Fe17 by Direct Electrochemical Reduction of Tb4O7-Fe2O3 Pellet in Molten Calcium Chloride

在CaCl2熔盐中直接电化学还原固态Tb4O7与Fe2O3(Tb∶Fe=2∶17)的混合 粉末, 一步制得了金属间化合物Tb2Fe17. 结合混合氧化物烧结片在850 ℃的CaCl2 熔盐中3.1 V电解不同时间段产物的成分分析探讨了还原机理：Fe2O3优先还原 成金属Fe, 随后Tb4O7粉末在Fe上还原逐渐生成Tb2Fe17. 采用不锈钢筛网电极 循环伏安法证明了Tb4O7在Fe上的欠电位还原.     

非水体系中电沉积稀土永磁功能合金膜

研究在尿素-NaBr-KBr-甲酰胺体系中电沉积稀土-铁系金属（La-Co）合金.用扫描电子显微镜（SEM）观察金属镧钴合金镀层表面形貌,结果表明,金属镧钴合金镀层较疏松,有裂纹,呈现银灰色;X射线衍射（XRD）分析表明稀土金属镧钴合金为LaCo5晶体;特征X射线谱（EDS）证明镀层由金属镧、金属钴和极少量的氧化物、氯、溴组成,单质镧的含量为29.07wt%,单质钴的含量为63.51wt%;La和Co的原子数比值约为1：5;X射线光电子能谱（XPS）经Ar离子对样品表面层溅射后,测定结果进一步证明,沉积层确为单质镧和单质钴.着重研究了La-Co合金的磁性,发现在室温下呈现顺磁性的La,当与Co形成合金后饱和磁矩接近于磁性金属Co.     

氧化热对铝合金硬质氧化膜的影响(英文)

采用自制的实验装置和硫酸电解液研究阳极氧化热对铝合金2024硬质氧化膜的影响。与氧化热由氧化膜传递到电解液中相比,氧化热由铝基体传递到冷却液中有利于氧化膜的生长,成膜速度、膜厚、致密度和硬度显著提高,并随着冷却液过冷度的增大而增大。氧化膜生长所需的冷却液过冷度与电解液过冷度、铝基体壁厚、氧化膜厚度、气泡覆盖特性参数以及电流密度有关。可通过控制冷却液温度来控制氧化膜的微观结构和性能。     

Deposition of cerium contained conversion films on LC4 alloy with square wave pulse method

Cerium contained conversion films were deposited on LC4 aluminum alloy using square wave pulse (SWP) in aCeCl3 solution with KMnO4 as the oxidant. Energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) were adopted to study the composition and the morphology of the film. It is found that the film is composed of Al, Zn, Cu,and small amount of cerium. The polarization curves of the specimens treated with SWP technique measured in 3.5% (mass fraction) NaCl solution reveal that the film thus formed inhibits both the anodic and cathodic process of the corrosion of the specimen. The immersion tests of treated specimens in 3.5% NaCl solution indicate that the corrosion resistance of the SWP treated specimen is better than that of the untreated and is equivalent to or even better than that of the traditionally electro-chemically treated specimens.     

Effect of combinative addition of strontium and rare earth elements on corrosion resistance of AZ91D magnesium alloy

The influencf of strontium（Sr） and rare earth（RE） elements on the corrosion behavior of AZ91D magnesium alloy was investigated by conventional corrosion testing and electrochemical measurements in 3.5% NaCl solution. After comparing the mass loss and hydrogen evolution of the samples, the microstructures of the alloys and the morphologies of their corrosion product films were characterized by electron probe microanalysis-energy dispersive spectrometry（EPMA-EDS） and Auger electron spectroscopy（AES）. Compared with individual addition of Sr or RE to AZ91D, the combinative addition of 0.5% Sr and 1% RE to AZ91D successfully decreases the corrosion rate further, which can be attributed to the depression of micro-galvanic couples, as well as the formation of more protective film due to aluminum enrichment. The combinative addition of strontium and rare earth elements to AZ91D magnesium alloy appears to be a promising approach to increase its corrosion resistance.     

稀土La对铁基耐蚀合金抗氧化性能的影响

通过X射线衍射(XRD)、扫描电镜(SEM)及能谱分析(EDS)等手段对不同La含量的铁基耐蚀合金850 ℃下的抗氧化性能进行了研究。结果表明,在850 ℃条件下,随着稀土La含量的增加,在一定程度上降低了合金的抗氧化性能,但氧化膜与基体的粘附性却得到了大大提高。La含量增加后,促进了氧的内扩散,使内氧化层呈树枝状深入合金基体,对氧化膜起到钉固作用。氧化膜主要由3个区域组成:外层是Fe₂O₃与CuO混合层,并含有少量CuFe₂O₄;中间层是以NiFe₂O₄为主的保护层,并含有少量的Fe₂O₃、NiO;内层则是以Fe₂O₃为主并含有少量NiO氧化物的内氧化区。