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针对制备EBSD样品的电解抛光工艺中的电压、电解液流速、电解时间、电解液温度和电解抛光面积等工艺参数进行调试与摸索,获得了DP590双相钢连退样品EBSD最佳电解抛光工艺参数。     

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。     

电解抛光法制备钛合金EBSD样品

采用5%的高氯酸乙醇溶液对TC4钛合金进行电解抛光,测得了相应的电解抛光特征曲线。随抛光温度升高,电解抛光特性曲线上拐点处对应的分解电压先减小后增大,20℃时达到最低。借助场发射扫描电镜(FE-SEM)分析了抛光电压、搅拌和抛光时间等参数对TC4钛合金抛光效果的影响,借助EBSD技术验证了抛光效果。TC4钛合金的最佳电解抛光条件:电解抛光温度20℃、电压28 V、电流密度0.98 A/cm2、搅拌、电解抛光时间25 s。     

电子背散射衍射的制样方法和影响花样质量的因素

概述了电子背散射衍射(EBSD)原理.EBSD试样的制备质量很大程度上决定着EBSD测试的可行性和花样的质量.介绍了各种抛光方法的优缺点,包括机械抛光、化学抛光、电解抛光和离子束处理等.总结了影响EBSD花样质量的因素,主要包括样品的状态、电镜参数的设置和数据获取软件参数的设置等.研究对于EBSD技术的初学者具有很好的...     

电解抛光工艺对 AP1000 管座焊接表面的改善作用

研究了AP1000上封头CRDM管座用焊接镍基合金的电解抛光工艺条件,探讨了电解抛光对其表面粗糙度和应力的改善作用。结果表明:焊接镍基合金的抛光电流密度应控制在0.3~0.5 A/cm2之间,抛光时间宜为2~5 min;电解抛光使表面拉应力大幅度减少,甚至产生压应力,这可抑制焊接镍基合金应力腐蚀开裂的发生。     

用转盘式电极对圆柱形表面镜面抛光

电解研磨镜面抛光无需熟练的操作技能和精密加工设备,就可使多种金属材料的表面成为镜面。本文阐述电解研磨镜面抛光的机理,用转盘式电极抛光圆柱面的基本方法及要点。     

高质量硬质合金EBSD样品的机械制样方法

EBSD技术在硬质合金及其涂层材料研究领域内的应用日益广泛,如何制备高质量的硬质合金EBSD样品是EBSD技术应用的关键。本文采用常规金相设备和振动抛光仪,解决了不同晶粒和结构的硬质合金EBSD样品的制备,并提出了系统的制样方法。机械研磨/抛光、振动抛光的参数选择和样品清洗彻底与否是该方法的关键因素。研磨采用金刚石磨盘70²0μm逐级研磨,以消除划痕;抛光选择由硬性至高弹软性抛光布配合金刚石抛光剂920μm逐级研磨,以消除划痕;抛光选择由硬性至高弹软性抛光布配合金刚石抛光剂9¹μm逐级抛光;振动抛光应用高弹性抛光布配碱性硅溶胶抛光液151μm逐级抛光;振动抛光应用高弹性抛光布配碱性硅溶胶抛光液15³0 min;彻底清洗样品,直至露出样品表面真实表面。同时为解决样品漂移问题,改进并设计了硬质合金EBSD镶样专用样品台。运用该方法制备了超细晶、细晶、大/小尺寸混合晶和粗晶等4种不同WC晶粒尺寸等级的硬质合金EBSD样品,并进行了相关实验及晶粒取向表征,结果充分证明本文提出的制样方法具有适用WC晶粒等级范围广,EBSD结果质量高的特点。     

表面处理对高强度的γ-TiAl合金在长期热暴露前、后疲劳性能的影响

研究了电解抛光和电解抛光+喷丸两种表面强化工艺对高强度细晶粒合金Ti-44Al-5Nb-0.85W-0.85B在长期热暴露(10000 h、700℃)前、后疲劳行为的影响。结果表明:在热暴露前,电解抛光+喷丸处理相对于电解抛光处理更能有效地提高该合金的疲劳性能。热暴露后,相对于电解抛光+喷丸,电解抛光的合金疲劳强度增加。在经历热暴露后,电解抛光处理的材料的疲劳强度有一定程度的提高。获得光滑无缺陷表面的电解抛光工艺比电解抛光+喷丸工艺更能有效地保持钛铝合金抗热暴露氧化的能力。     

钽板的电解抛光和化学抛光

本文论述了电解抛光和化学抛光对钽板性能的影响,给出了钽阳极溶解曲线和溶解速度曲线,并讨论了抛光机理。研究结果表明：钽板的表面粗糙度随抛光前的表面粗糙度的升高而增高,但抛光后表面的反射系数提高较小,电解抛光后的表面粗糙度比化学抛光的高。试验发现,抛光后的钽板经轧制后,其表面反射系数较轧制前提高了近30%。     

AP1000蒸汽发生器电解抛光技术研究

针对AP1000蒸汽发生器材料、焊接及结构特点,研究了电解抛光对降低其粗糙度、消除表面毛刺和凸起及表面形貌的影响。结果表明:电解抛光能改善AP1000蒸汽发生器表面状态。     

电解质等离子抛光在高碳微合金钢上的应用研究

目的提高金属针布产品(高碳微合金钢)的表面质量,降低针布产品的表面粗糙度值,有效提升产品的使用效果。方法采用电解质等离子抛光工艺在针布产品上展开工艺研究,探索了不同电解质浓度(无机盐质量分数)、不同生产速度和不同电解质等离子抛光单元组数对针布表面粗糙度的影响。利用非接触式粗糙度扫描仪测试粗糙度Ra,以此对针布表面的抛光质量进行表征。结果采用电解质等离子抛光工艺可以实现钢铁材料的表面抛光,抛光后不仅有效地去除了针布表面的氧化皮,并且表面平整且达到镜面效果。最佳工艺参数(电解质无机盐质量分数2.75%,走线速度40 m/min,电解质等离子抛光单元4组)下,表面粗糙度Ra值达到了0.11μm。结论电解质等离子抛光工艺成功地应用于钢铁材料上,且实现了非接触式连续抛光工艺,既不损伤工件,又实现了表面的光亮平整,还具有环境友好、节能和生产效率高等特点。     

The Rate-Determining Stage in the Anodic Dissolution of Metals

An experimental study has been made, using the potentiostat technique, of the limiting current densities of metal dissolution in electrolytic polishing solutions. The limiting current densities show the features expected for diffusion currents, and the effect of the addition of the metal dissolution product to the electrolyte indicates that it is the diffusion of this substance away from the anode which determines the overall rate of the electrode reaction. Electrolytic polishing does not occur until the limiting current density has been reached, and experiments with composite anodes show that the diffusion current densities at peaks in the surface are much higher than at cavities. These observations are interpreted by a simple diffusion layer treatment of the kinetics of the anode reaction, and their bearing upon the mechanism of electrolytic polishing is reviewed. Some practical recommendations for electrolytic polishing are made.     

Study on the characteristics of Magneto-Electrolytic-Abrasive Polishing by using the newly developed nonwoven-abrasive pads

Recently, advanced technologies in general industry demand that the production of precision parts is much more precise and efficient. However, most of the precision finishing technologies cannot satisfy both the finishing efficiency and surface finishing at the same time. Magneto-Electrolytic-Abrasive Polishing (MEAP) is a new ultra precision machining technology, which combined many kinds of energy, has been deeply investigated under this urgent demand and its effect has been much improved. The method of MEAP for those difficult-to-cut materials has become an important technique in the precision machining field. In particular, the nonwoven abrasive pad, which is a kind efficient matching polishing material used in MEAP system, has been developed. Because nonwoven abrasive pads can cut off the oxide membrane which appears during electrolytic polishing process without time delay and there are no scratches left on workpiece surface, it has been proved that it is a high efficiency and economic polishing material. In this study, the basic properties of nonwoven abrasive pads have been explained and the developed processes for SiC and Al₂O₃ nonwoven abrasive pads have also been described. Their polishing abilities on difficult-to-cut materials of Cr-coated rollers have been tested according to different kinds of pad. Through using the life test experiment, their economic benefits in Magneto-Electrolytic-Abrasive Polishing systems will be discussed.     

表面状态对疲劳塑性变形局部化的影响

目的研究不同的表面状态对Waspaloy~(TM)镍基高温合金塑性变形局部化的影响,确定最优的评价塑性应变局部化的三维表面粗糙度参数。方法对两组Waspaloy~(TM)高温镍基合金先进行机械抛光至0.02mm,然后分别进行电解抛光和化学蚀刻,得到不同的两种表面状态。通过制作标准试样进行疲劳试验得到疲劳寿命,并采用原子力显微镜、扫描电子显微镜和三维表面轮廓仪分析Waspaloy~(TM)镍基高温合金在电解抛光和化学蚀刻处理前后的表面形貌以及裂纹萌生形貌。结果试样经过电解抛光和化学蚀刻后,电解抛光表面质量更好,三维表面粗糙度Sa(表面算数平均偏差)分别是0.001、0.018mm,经过疲劳试验后的值分别为0.024、0.026mm,表面粗糙度参数Sp(表面最大峰高)均为0.131mm。电解抛光试样的疲劳寿命为800,化学蚀刻试样的疲劳寿命为700。经过化学蚀刻和电解抛光的试样疲劳裂纹均是从滑移带处开始产生,并沿滑移带扩展。结论表面状态影响材料的疲劳寿命,表面粗糙度小的试样疲劳寿命长。三维表面粗糙度参数Sp适用于描述材料疲劳塑性应变局部化,其临界值揭示了材料裂纹萌生。     

等离子抛光时间对3D打印多孔钛表面粗糙度的影响

利用3D打印技术制作仿天然骨的多孔钛骨科植入物具有广阔的前景,等离子抛光技术作为表面技术的一种,可有效去除3D打印多孔钛零件表面附着的颗粒物,降低表面粗糙度。采用三重扫描激光显微系统分析了不同等离子抛光时间下多孔钛零件外表面及内层孔结构外表面的表面形貌并测量其表面粗糙度值。结果表明,抛光时间越长,表面越顺滑,表面粗糙度越低,抛光时间是影响表面粗糙度的重要因素。根据抛光时间与表面粗糙度的拟合曲线,得出了在保证零件内外表面的表面粗糙度在最优值范围下的抛光时间区间。     

Elektrolytisches Bearbeiten von NiTi‐Formgedächtnislegierungen

Electrolytic processing of NiTi shape memory alloys Electrolytic procedures are of great interest to produce components made of NiTi‐shape‐memory alloys (NiTi‐SMA). Products of medical technology and micro system technology as well as components with elaborately manufactured structures or outlines are of special importance. In literature you can hardly find any systematic investigations about the electrolytic processing of NiTi‐SMA and the surface structurings achieved in the process. The paper at hand shows that it is possible to polish NiTi‐SMA in austenitic and martensitic state and to achieve satisfactory results (smooth surfaces). In the process of polishing in austenitic state, however, a formation of waves due to segregation occurs after longer periods of polishing. In the course of electrolytic polishing in martensitic state the current density is more uniformly and the formation of waves is omitted. The surface polished in martensitic state shows a pseudo‐martensite‐relief after the conversion into austenite. This relief structure offers additional possibilities in the substrate preparation for coatings. Within this process electrolytic etching of NiTi‐SMA is also appealing. It was possible to show that defined, finely structured surfaces can be manufactured.     

Mirror surface grinding for brittle materials with in-process electrolytic dressing

Use of a diamond wheel with superabrasive is required for mirror-like surface grinding of brittle materials. However, conventional dressing methods cannot apply to the diamond wheel with superabrasive. Recently, an electrolytic dressing method was developed for use with a cast iron-bonded diamond wheel and superabrasive. This technique can replace lapping and polishing. Using electrolytic dressing, surface roughness of the workpiece was improved significantly, and the grinding force was very low and the continuity of the grinding force was also improved. The purpose of this study was to achieve mirror-like surface grinding of ferrite with electrolytic dressing of a metal-bonded diamond wheel. For application of ultraprecision grinding for brittle material, superabrasive, air spindle, and in-process electrolytic dressings were used. Additionally, the effects of pick current and pulse width on ground surface were investigated, and suitable dressing conditions for ferrite were determined.     

Electrochemical and XPS studies of AISI 316L stainless steel after electropolishing in a magnetic field

The thermodynamic stability and corrosion resistance of surface oxide layer are the most important features of stainless steels. Electrochemical polishing (EP) is the most extensively used surface technology for austenitic stainless steels. We have modified this surface technology by introducing a magnetic field to the system. With this new process called the magnetoelectropolishing (MEP) we can improve metal surface properties by making the stainless steel more resistant to halides encountered in a variety of environments.In this paper, the corrosion research results are presented on the behaviour of the most commonly used material - medical grade AISI 316L stainless steel. The corrosion investigations have been concerned on the open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and polarisation curves studies in the Ringer’s body fluid under room temperature (25 °C). The X-ray photoelectron spectroscopy (XPS) was performed on 316L samples after three treatments: MP - abrasive polishing (800 grit size), EP - conventional electrolytic polishing, and MEP - magnetoelectropolishing. The comparison of the corrosion behaviour of the stainless steel’s surface after these processes was also carried out. The purpose of XPS studies was to reveal the surface film composition and the reason of this modified corrosion behaviour. It has been found that the proposed MEP process modifies considerably the composition of the surface film and improves the corrosion resistance of the same 316L SS studied.     

Surface finishing of biodegradable stents

The surface conditions of stents influence their polymer/drug coatability, rate of degradation, and ultimately their mechanical strength, ability to expand, and service lifetime. This paper describes new polishing tools developed to mechanically polish entire biodegradable magnesium-alloy stents. Use of the new tools removes material from the peaks of the stent surfaces and enables surface smoothing equivalent to electrolytic polishing (EP) but with less material removal, helping extend the stent service life. Static immersion tests using Dulbecco’s modification of Eagle medium solution demonstrated that stents polished using the new tools had a rate of degradation about 40% lower than EP-processed stents.