日本:另类资源大国

日本是一个资源相当匮乏的国家，其资源绝大部分依靠进口。而稀有金属的供应状况更是面临诸多困难。因此，该国将目光瞄准了隐藏在海水、手机电池和电子元件板中的稀有金属。据日本经济产业省的定义，在液晶显示器、手机和电脑的电池中使用的有包括铟、钴等在内的31种稀有金属。日本是个电子大国，如果将这些电子垃圾中含有的稀有金属数量估算—下，日本从另外一个角度上来说，真的是一个资源大国。     

Electropolishing parameters of NiTi alloy

Electropolishing has been used in NiTi alloy in several fields for its special characteristics, but its essential details and electropolishing mechanism have not been reported yet as a demand from business competition, which, to a great degree, restricts the application and extension of the electropolishing technology. The effect of processing parameters on nitinol electropolishing was explored. Besides the electrolyte, other factors that influence the electropolishing are temperature, current density, time, spacing between anode and cathode, electrolyte stirring, etc. Studies on the effect of the temperature on the electropolishing process show that the higher the temperature is, the bigger the electropolishing rate is, following the near Gauss law. The relationship between the temperature and the surface roughness follows a near parabolic law, and the relationship between the temperature and the surface reflectivity follows a near sigmoidal law. The relationship between the electropolishing voltage and the current density follows a near cubic law, while that between the electropolishing rate and current density follows a near linear law. The relationship between the electropolishing rate and the time follows a near sigmoidal law. The practical spacing between anode and cathode is confirmed by the Hall bath experiment.     

Electropolishing technique of Hastelloy C-276 alloy

Preparing a highly textured,flawless YBa_(2-)Cu_3O_7(YBCO)layer by ion-beam-as sis ted deposition(IBAD)requires a substrate with a smooth surface.In this paper,smooth tapes of Hastelloy C-276,a common template alloy,were prepared by electrochemical polishing,and the surface roughness the tapes was investigating by atomic force microscopy and scanning electron microscopy.By analyzing these results,it was discussed how the processing parameters affect the surface roughness,and it is found the following optimized processing parameters:current density of 0.104 A·cm~(-2),temperature of 50℃,plate spacing of 9 cm and time of 150 s.With these optimized parameters,the substrate roughness decreases to less than 5 nm,meeting the requirements of IBAD.     

NiW合金基带电化学抛光过程研究

采用硫酸溶液作为抛光液对轧制辅助双轴织构技术制备的Ni5W合金基带进行电化学抛光,在不同的抛光液浓度下获得了表面状态不同的基带。利用X射线光电子能谱(XPS)、X射线衍射(XRD)、扫描电镜(SEM)等手段研究了抛光过程中表面物质相成分及成因。结果表明:抛光液浓度较低时基带表面会形成过量的氧化物和H2WO4,造成表面选择性溶解过程紊乱,导致无法抛光。通过优化抛光液浓度可在基带表面获得适当厚度的固体层和粘液层,电流通过时可获得良好的抛光效果。     

The Electropolishing of Chromium and Its Alloys

A technique for electropolishing chromium and chromium-based alloys has been devised. The polishing baths contain orthophosphoric acid, sulphuric acid and water, or orthophosphoric acid alone. Conditions are given for obtaining rapid smoothing, polishing and electroetching of the surface for metallographic examination. The probable mechanisms of electropolishing, and of anodic passivity on chromium in the polishing bath, are discussed.     

电解抛光法制备铝合金EBSD试样方法研究

目的 为在导电单相金属中获得高质量EBSD试样表面,研究电解抛光法制备铝合金试样的方法,并提供理论支持。方法 基于Jacquet黏膜模型和金属阳极原理,提出利用阳极极化曲线、电流-时间曲线和扫描电镜二次电子图像获得电解抛光工艺参数,批量制备铝合金EBSD试样的理论方法。采用恒电位法中的静态法记录稳定的电压-电流走势,以获得电流稳定的实验时间,在90 s内进行各电压下的电解抛光实验,获得电压与稳定电流的对应关系,并绘制阳极极化曲线。电流由持续稳定转至持续上升后的斜率与电压横坐标相交处为理论最低分解电压值。结合扫描电镜二次电子图像在最低分解电压以上观察抛光表面。结果 获得最优抛光电压值为31 V。利用电流随时间的变化曲线,结合黏膜模型分析,并通过扫描电镜二次电子图像验证,最优电压下的最佳抛光时间为12 s,该值是电流-时间曲线中的电流最低点。此工艺使制备的铝合金EBSD样品标定率为97%,是理想的电解抛光工艺。结论 采用阳极极化曲线获得的最优电压和最优电压下的最小电流规律由Jacquet黏膜模型支持,其所获得的电解抛光工艺能够制备出优质的样品表面,也能够为其他金属块体导电材料和其他需要电解抛光的实验类型提供获得最佳电解抛光工艺值的理论方法。     

The Electropolishing of Nickel in Urea-Ammonium Chloride Melts

Nickel may be electropolished in melts based on urea containing 5–20% w/w of ammonium chloride and 0–3·5% w/w of anhydrous nickel chloride, held at 120–135°C. The optimum applied potential difference across a cell with a vertical anode spaced 1 cm. from the cathode is 2·5–3 v., and the optimum current density is 0·15—0·4 amp./cm.². Considerably higher current densities also give polishing but lead to much gas evolution and increase the tendency to pitting; still higher current densities produce a grey film on the metal surface. The melts age with time, so that the optimum current density falls, and become useless after about three days at temperature; they are partially restored by the addition of fresh urea.

There is an induction period before polishing begins (shorter the higher the current density) during which the metal dissolves normally; the onset of polishing is determined by a rise of anode potential (1·5–1·8 v.) similar to that found in anodic passivation. The evidence suggests that the rise is due, as in passivation, to the formation on the anode surface of a compact film, which during the polishing process, however, dissolves at its outer surface as fast as it is formed. It is suggested that this mechanism is general in electro-polishing, and it is shown that it can account for the avoidance of etching characteristic of the process.     

Electropolishing of cylindrical cavities under natural convection conditions

Limiting currents were measured for the electropolishing of cylindrical copper cavities in phosphoric acid under natural convection conditions. Variables studied were cavity diameter, cavity depth and phosphoric acid concentration. Within the range studied, cavity diameter and depth were found to have little effect on the polishing limiting current. Limiting current was found to decrease with phosphoric acid concentration. Limiting current data were correlated to other variables in terms of the following dimensionless, mass transfer correlation Sh = 0.11(ScGr)^0.35.     

Electropolishing of nickel and cobalt in deep eutectic solvents

Electropolishing is a common method for decreasing surface roughness and removing surface irregularities. In this paper the electropolishing of nickel and cobalt are successfully demonstrated in a deep eutectic solvent, comprising a 2:1 molar mixture of ethylene glycol and choline chloride. Voltammetric and electrochemical impedance studies were used to characterise the polishing mechanism and show that film formation occurs prior to polishing. Scanning electron microscopy and atomic force microscopy were used to characterise the morphology before and after polishing and 3D optical microscopy was used in-situ to observe film formation during polishing. This study shows that the impact of film formation and subsequently mass transport are responsible for electropolishing of both metals in the choline chloride-based ionic liquid.     

Note on a Convenient Method of Electropolishing Aluminium Alloys

The general problem of electrodeposition of metallic coatings on to active metal substrates is briefly discussed. A detailed study of the electrodeposition of copper from a bath containing copper acetate dissolved in acetic acid-pyridine solutions containing 20% by volume of pyridine is then presented. The variation of cathode current efficiency as a function of current density and temperature was studied at current densities in the range 1 to 12 A/ft² at temperatures from 25° to 62·5°C. At 6 A/ft², temperature had the most marked influence on current efficiency which increased from ~ 60% at 25° to a maximum value of 112% at 50°C. A wide variety of types of coating were obtained from the bath by appropriate variation of the deposition conditions. These varied from ductile, matt, adherent coatings, with columnar structures resembling those from acid copper baths, to ductile, high reflecting coatings with layered structures which were similar to those obtained from aqueous baths in the presence of addition agents. The results of the investigations are discussed with respect to present knowledge concerning the chemistry of the acetic acid-pyridine system.     

电解抛光提高镍钛合金心血管支架表面性能

植入高性能的心血管支架是治疗心血管疾病的主要手段,而支架的制造工艺决定了其表面性能。采用乙二醇-氯化钠无毒电解液电解抛光工艺来提高镍钛合金心血管支架的表面完整性和生物相容性。试验结果表明,该工艺制造镍钛合金心血管支架的表面完整性和生物相容性明显改善:镍钛合金心血管支架表面光亮平整,没有熔渣和热影响区,表面粗糙度达到Ra 85.5 nm;镍钛合金心血管支架表面化学成分发生改变,表面形成二氧化钛保护膜,阻止了Ni离子析出,且电化学腐蚀性能明显提高,有效改善了支架生物相容性;该工艺采用醇-盐无毒电解液进行抛光,提高了工艺对环境的友好性。此外,该工艺解决了镍钛合金心血管支架制造领域的关键技术难题,制造出了性能优良的镍钛合金心血管支架,为高质量心血管支架制造提供了科学依据。     

Electropolishing of Silver in Water-Organic Solutions of Potassium Thiocyanate

The anodic behavior of silver in aqueous and water-glycerol solutions of potassium thiocyanate is studied on motionless and rotating-disk electrode. The appearance of the limiting current is explained. Optimal solution compositions and conditions for the process (which ensure metal polishing) are suggested.__________Translated from Zashchita Metallov, Vol. 41, No. 4, 2005, pp. 386–389.Original Russian Text Copyright © 2005 by Balmasov, Koroleva, Lilin.     

硫酸甲醇体系中电解抛光钽的实验研究

采用硫酸甲醇体系对钽进行电解抛光,并对其抛光性能进行了研究,测定了不同配比时电解液中钽的阳极极化曲线,研究了电解液配比和电压对钽表面质量的影响.在搅拌速率为16 m/s、电解液温度为0℃、时间为3 min、硫酸甲醇体积比为1:7时,电压在20 V左右抛光效果较好、钽表面均方根粗糙度Rq小于30 nm,不仅能够满足钽材表面精饰加工需求,而且能够满足EOS靶用标准材料薄膜对表面质量要求.     

Electropolishing of 316L stainless steel for anticorrosion passivation

316L stainless steel is deemed an indispensable material in the semiconductor industry. In many instances, the surface of the production equipment needs to be treated for low-corrosion passivation, good finish, weldability, and cleanliness. The process characteristics of electropolishing meet these requirements well. The current study investigates the effects of the major processing parameters on the anticorrosion performance and the surface roughness. The electrolyte with 10% water content and a ratio between H₂SO₄ and H₃PO₄ of 4 and 6 has been proven to be successful, showing no corrosion pitting points on the specimen surface. The electrolyte temperature of 85±10 °C and the electrical current density of 0.5 to 1.0 A/cm² are found to be optimal. The processing time beyond 3 to 5 min produces no further improvement. The addition of 10% glycerin provides a very fine surface (maximum roughness of 0.05 μm), while the anticorrosion performance is deteriorated. The results obtained are useful for the manufacture of the semiconductor equipment.     

Electropolishing of high-purity aluminium in perchloric acid and ethanol solutions

The electropolishing behaviour of high-purity aluminium with ultrasonic agitation was investigated in ethanol-perchloric acids by using anodic polarization measurement, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and atomic force microscope (AFM). The results show that the electropolishing behaviour of the aluminium is under mass-transfer control and Al³⁺ is suggested as the governing species for the salt film mechanism during anodic dissolution in limiting current plateau.