聚焦离子束在预镀镍电池壳成型件缺陷分析中的应用

首次应用聚焦离子束(Focused Ion Beam,简称FIB)技术对镀镍电池钢壳表面微小点缺陷进行准原位截面切割观察,并结合扫描电镜及X射线衍射方法进行对比分析。结果显示,作为一种专用的薄片制作技术,单束FIB技术还是一种重要的准原位表征技术,能获得成分、晶粒变形程度、晶体取向衬度信息,为揭示镀镍电池壳表面缺陷在成型过程中演变的组织特性提供有力的证据。     

电池壳电沉积技术的发展现状及趋势

随着各种碱性锌锰、锂离子、镍氢电池在国内的普遍使用,电池钢壳的用量日益增加.为了增加其导电性、可焊性及耐蚀性,必须对电池钢壳表面电镀镍或作其他电镀.电池钢壳(盲孔)是深孔零件,其孔长比大于1∶3,滚镀镍难度很大,采用普通滚镀镍方法不能解决这个问题.电池钢壳要求外壁光亮,内壁白亮均匀、最底部处镍镀层厚度不低于0.2 μm(最薄处的镍层厚度),且对镍镀层孔隙率要求高,有中性盐雾要求.国内从20世纪80年代中期开始对电池钢壳进行了电镀试验研究,90年代初开始批量生产.目前,电池钢壳电镀技术渐渐趋于成熟,但尚有问题需要解决,如镀层孔隙率、电池壳存放期,镀层厚度内外差异等.近年来,电池钢壳(盲孔)的滚镀技术一直是研究热点,一般电镀亮镍工艺很难保证其内表面的镍镀层全部镀覆均匀,即使采用化学镀镍或焦磷酸盐、HEDP等镀镍工艺也存在种种问题.高校、研究院所和企业针对电池钢壳的电沉积进行了一系列研究,主要是从产品、工艺(添加剂)、设备等方面进行了研究和开发.     

镀镍石墨粉的电化学性质

利用化学镀方法在石墨粉表面镀覆了一层均匀、完整的金属镍,研究了镀镍石墨粉电极及镀镍石墨粉作为ＭＨ／Ｎｉ电池镍电极导电剂时的电化学性质。实验表明,石墨粉表面镀覆金属镍可增另其电化学活性;用镀镍石墨粉作为电极导电剂时,可以改善镍电极的导电性能,降低电池内阻,提高正极活性物质的利用率,且电池的循环稳定性好,以１Ｃ倍率充放电循环１２０就衰减。     

镁合金化学镀镍技术的研究现状及发展趋势

通过化学镀镍来改善镁合金表面耐蚀性能是一种环保型的表面处理工艺方法。介绍了镁合金化学镀镍技术的应用背景和镁合金化学镀镍技术的研究现状以及目前存在的问题。最后,对新型镁合金微弧氧化-化学镀镍复合工艺及其应用前景进行了探讨。     

前处理工艺对钛合金化学镀镍层结合力的影响探讨

化学镀镍作为一种经济适用的材料表面处理技术,已经广泛应用于各个领域,钛及钛合金表面化学镀镍可提高其表面硬度、耐蚀性及耐磨性。镀层与基体材料的结合力是衡量化学镀件质量的重要指标之一,而前处理工艺对化学镀镍层结合力起到决定性的影响。本文结合近期研究成果,探讨了除油、酸洗、活化及其它特殊前处理工艺对钛合金化学镀镍层结合力的影响。     

表面活性剂对化学镀镍影响机理的研究

目的 探究十二烷基硫酸钠(SDS)、十六烷基溴化吡啶(CPDB)和OP-103种表面活性剂在化学镀液中对镀镍过程的影响,改善PCB化学镀镍层的不均匀现象.方法 通过化学镀试验,对镀镍层的厚度变化进行研究.利用电化学分析测试,研究表面活性剂对化学镀镍腐蚀的影响.使用扫描电镜(SEM)对镀镍层表面微观形貌进行表征.运用Forcite模块中的COMPASS力场进行分子动力学计算,研究表面活性剂分子在镍层表面吸附过程中的能量变化.结果 通过化学镀试验,发现加入适量的表面活性剂能够增加镀镍层的厚度,SDS、CPDB和OP-10能够提高镀镍层的均匀性.电化学测试结果表明,3种表面活性剂与Cu-Ni表面吸附作用的强弱顺序为SDS>CPDB>OP-10.通过扫描电子显微镜测试,发现添加表面活性剂后,镀层表面平整性良好,颗粒分布和大小均匀,均匀性顺序为OP-10>CPDB>SDS,与镀速的变化呈负相关.分子动力学模拟计算结果表明,3种表面活性剂都能自发地吸附在镍表面,其温度波动和能量波动都在25 ps达到稳定,吸附稳定.OP-10、CPDB、SDS吸附模型作用能分别为–3338.61、–3681.28、–4158.18 kJ/mol.结论 在化学镀镍液中加入表面活性剂,可在一定程度上有效提高化学镀镍层的均匀性,并且提升镀镍速率.该研究为化学镀镍过程中表面活性剂的选择提供了理论基础.     

碳纤维的化学镀镍

提出一种碳纤维的化学镀镍技术,研究了镀层的形成过程和显微组织。结果表明:用化学镀技术在碳纤维表面镀镍是成功的,镀层均匀连续。当镀层厚度小于0.3μm时,在碳纤维表面呈不连续分布的镍膜,大于0.8μm时,在连续分布的镀层上镍以枝晶状沉积出现。应用镀镍碳纤维制造的铝基复合材料,没有观测到明显的界面反应。     

5号碱性电池壳体整体镀Ni新工艺的研究

提出了１种５号碱性电池壳整体镀镍的新工艺,首先,采用化学镀镍：其化,进行滚镀亮镍,使壳体内外获得光亮,细致,均匀,韧性,附着力,耐蚀性好的镀层。     

化学镀镍磷及镀前处理

前言化学镀镍磷是提高金属表面耐磨性的一种表面强化力法。由于其处理温度低、热处理变形小、镀复层硬度达HRC60以上、镀层色泽美观、抗蚀性良好,故在钢铁零件上得到了应用。随着化学镀镍磷技术的不断发展和完善,在铝合金、不锈钢等材料领域也得以开发和使用。因此,化学镀镍磷低温表面强化     

镁合金表面化学镀Ni-P合金研究

镁是一种极活泼的金属,其合金具有优异的性能,是得到广泛应用的重要原因.然而,镁合金在各介质中的不耐蚀,其应用受到了制约.据文献报道,已有多种方法被应用到镁合金上,但效果都不很理想;而化学镀镍技术是近年来发展较快的一种表面处理方法.进一步探讨了在AZ91D表面上进行化学镀镍的研究过程:通过多次试验确定了镁合金的前处理方案,研究了在酸性条件下镁合金表面直接化学镀镍的一套工艺路线,配置简单,操作方便,避免了预镀中间层的麻烦.并且测定了镀层的厚度、显微硬度,观察了镀态的金相组织;热震实验和划痕实验的结果表明镀层与衬底具有良好的结合力.     

Revealing substructure in clock-rolled Ta aided with triple focused ion beam

Clock rolling was developed to make deformation microstructure homogenize in high-purity Ta. The substructure of deformed Ta was revealed by electron back-scatter diffraction(EBSD) technique aided with triple focused ion beam(FIB). The results indicate that the triple FIB method can produce a mirror surface required by EBSD analysis. The clock rolling works well for the homogenization of deformed microstructure. Particularly,the local stored energy in {111} orientated grains is largely reduced by clock rolling, whereas it is enhanced in {100}orientated grains because of the occurrence of grain subdivision.     

Effects of focused ion beam milling on the compressive behavior of directionally solidified micropillars and the nanoindentation response of an electropolished surface

Focused ion beam (FIB) milling is the typical method used to fabricate micropillars to study small-scale plasticity and size effects in uniaxial compression. However, FIB milling can introduce defects into the milled pillars. To investigate the effects of FIB damage on mechanical behavior, we tested Mo-alloy micropillars that were FIB milled following directional solidification, and compared their compressive response to pillars that were not FIB milled. We also FIB milled at glancing incidence a Mo-alloy single-crystal surface, and compared its nanoindentation response to an electropolished surface of the same crystal. Implications for the interpretation of data obtained from FIB-milled micropillars are discussed.     

Scaling the response of microscale compression molding of elemental Cu in the presence of dynamic recrystallization

Replication of metallic high-aspect-ratio microscale structures by direct compression molding is a promising microfabrication technique. In this paper, the micromolding response of elemental Cu is measured as a function of molding temperature. Companion tensile testing of macroscale Cu specimens was carried out at the corresponding molding temperatures. Microstructures of tensile tested macroscale Cu specimens and molded Cu specimens were characterized by combining focused ion beam (FIB) sectioning and imaging with ion-induced secondary electrons (ISEs). At all temperatures tested, measured tensile stress–strain curves for Cu show clear evidence for the occurrence of dynamic recrystallization (DRX) within macroscale tensile specimens. Additional FIB sectioning and imaging with ISEs of molded Cu specimens provide microstructural evidence for the occurrence of DRX during molding. The present results show that, even in the presence of DRX, an appropriate one-parameter scaling continues to reduce the molding response to a universal function independent of the molding temperature.     

Cu/Nb纳米多层膜延性及其断裂行为

通过单轴拉伸试验研究恒定调制周期的聚酰亚胺基体Cu/Nb纳米金属多层膜的延性对调制比的依赖性,并采用聚焦离子束／扫描电子显微镜(FIB/SEM)截面定量表征技术深入分析多层膜的异质约束效应对断裂行为的影响.结果表明随着调制比的增加,多层膜的延性单调减小,出现由剪切型向张开型断裂模式的转变.当调制比小于某一临界值时,调制周期越小,多层膜延性越高;反之,则多层膜延性越差.这是由于软相Cu层对脆相Nb层中萌生的微裂纹扩展的约束作用.     

Three-dimensional investigation of particle-stimulated nucleation in a nickel alloy

By combining a focused ion beam (FIB) microscope with a field emission gun scanning electron microscope, it is possible to sequentially mill away ∼50 nm sections of a material by FIB and characterize, at high resolution, the crystallographic features of each new surface by electron backscatter diffraction (EBSD). The successive EBSD maps are subsequently combined to generate three-dimensional crystallographic maps of the microstructure. FIB-EBSD tomography was used to investigate the deformation and recrystallization behaviour of a nickel alloy containing coarse silica particles. The technique demonstrated unambiguously the influence of particle diameter on the misorientations generated within particle deformation zones and showed that particle-stimulated nucleation (PSN) of recrystallization occurred at particles greater than ∼1 μm. PSN also often generated groups of contiguous grains separated by both coherent and incoherent twin boundaries. It was found that much of the behaviour observed using FIB-EBSD tomography is not clearly evident in two-dimensional EBSD micrographs.     

Fatigue damage initiation and growth from artificial defects in Zr-based metallic glass

An array of well-defined and micrometer-sized circular and line defects were produced on the surface of Zr-based bulk metallic glass bend specimens using a focused ion beam (FIB) in order to study the effect of the defect size, orientation and shape on fatigue damage initiation and growth. Damage evolution was recorded using a surface-replicating technique. Damage was observed to initiate and grow as shear bands or mixed-mode cracks before reaching a characteristic length when they abruptly changed growth direction and propagated orthogonal to the maximum stress axes. Additionally, specimens with circular defect pairs were fabricated so that defect interaction under fatigue loading could be observed. Analysis of the stress state around the defect pairs indicated that damage initiation occurred in regions of highest equivalent (von Mises) stress. Stress-life measurements for bending specimens with FIB surface defects were found to be similar to those for bending specimens without defects at the same applied stress amplitude.     

The focused-ion-beam microscope—More than a precision ion milling machine

The focused-ion-beam (FIB) microscope has evolved into an important microstructure characterization instrument. The capability of high-resolution imaging using both secondary electron and secondary ion signals has made the FIB microscope a unique imaging tool. Stress-free cross sectioning using the primary gallium ion beam provides valuable microstructure information beneath the specimen surface. In addition, FIB techniques are often preferred to prepare transmission-electron microscope (TEM) specimens, which are frequently impossible to make by any other conventional methods. In this paper, various FIB microscopy applications in microstructural characterizations are discussed using examples from recent research, and conventional FIB-TEM specimen preparation techniques are illustrated.     

Direct imaging of native passive film on stainless steel by aberration corrected STEM

A cross-section of a native passive film on a commercial type 304 stainless steel was directly imaged and characterized using an aberration corrected STEM-EDS in combination with FIB sectioning. The technique demonstrated an enrichment of Cr in the lower part of the passive film, and a depletion of Cr and an enrichment of Ni in the matrix side closest to the passive film/matrix interface in accordance with previous studies, further proving the advantage of this technique with respect to spatial resolution. That is, the STEM-EDS showed a compositional profile with higher spatial resolution compared to AES which has been mainly used for this type of investigation. The technique will be applicable to the investigation of nm to sub-nm compositional fluctuation of passive films, steel surfaces adjacent to inclusions and grain boundaries postulated as an initiating site of pitting corrosion or stress corrosion cracking (SCC).     

PCSK9抑制剂对冠心病患者血脂及炎症因子的影响

目的：观察PCSK9抑制剂对冠心病患者血脂水平及常见炎症因子的影响。方法：回顾性分析2020年4月至2021年6月期间入住上海市东方医院心内科的201例冠心病患者的临床资料。根据患者用药情况分为PCSK9抑制剂治疗组（他汀+PCSK9抑制剂，n=101）和对照组（单纯他汀治疗组，n=100），治疗1个月后复查血脂、血常规、C反应蛋白（CRP）及纤维蛋白原（FIB）等指标，比较用药前后血脂及炎症因子的变化情况。结果：治疗前，两组患者血脂、血常规、CRP及FIB等指标无统计学差异（P>0.05），治疗1个月后PCSK9抑制剂组同治疗前相比，总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）、小而密低密度脂蛋白（sdLDL）及脂蛋白(a)（Lp(a)）水平均显著降低（P<0.05）；白细胞计数（WBC）、CRP、中性粒细胞计数（N）、FIB水平均显著降低（P<0.05）。PCSK9抑制剂组同对照组相比，TC、高密度脂蛋白（HDL）、LDL-C、CRP、FIB水平有明显变化（P<0.05），结果有统计学意义。结论：PCSK9抑制剂不但可以降低LDL-C水平，对改善Lp(a)水平也有效果。PCSK9抑制剂可以降低CRP、FIB水平，提示可以部分改善冠心病患者外周血的炎症水平。     

Fabrication of 3-D Submicron Glass Structures by FIB

The fabrication characteristic of focused ion beam (FIB) for Pyrex glass was investigated. FIB has several advantages such as high resolution, high material removal rates, low forward scattering, and direct fabrication in selective area without any etching mask. In this study, FIB-etched Pyrex glass was used for fast fabrication of 3-D submicron structures. A glass structure with 0.39 μm in width was fabricated. The experimental results in terms of limiting beam size, ion dose (ion/cm²), and beam current are discussed. The influence of XeF₂ gas on FIB glass fabrication was investigated.