镍铁合金电镀工艺存在的问题及解决方法

镍铁合金电镀工艺近年来有较大发展,并得到了广泛的实际应用。实践证明,镀层为含铁20～45％的光亮镍铁合金,其性能与亮镍镀层相同,甚至更好;尤其是用铜或黄铜打底,含铁量为20～45％的合金镀层,厚度小于12.7微米(如2.54微米)时,其效果比用同样厚度的亮镍镀层更好。为了节约更多的金属镍,目前各国都在努力研究把镍铁合金镀层中的铁含量提高到最大值。国内最近的研究成果表明,在以镍铁合金电镀液为基的复合电镀工艺中     

电沉积镍基复合镀层的研究进展

电沉积法是目前制备镍基复合镀层的重要方法。介绍了不同电沉积法的特点,综述了电流密度、镀液pH、表面活性剂、第二相颗粒含量和尺寸等工艺参数对镍基复合镀层质量的影响,总结了镍基复合镀层的种类及应用现状,最后对电沉积镍基复合镀层的未来发展方向进行了展望。     

微机电系统用电铸镍铁合金的制备及其电磁性能

研究了电铸镍铁合金制备过程中工艺条件对电铸层成分的影响,获得含铁质量分数20%电铸层的最佳工艺条件为镀液硫酸亚铁含量6 g/L、pH值2.5、温度55℃、电流密度3.5 A/dm2;讨论了镀层形貌及电磁性能的变化关系.结果表明:制备的镀层表面光亮、结构致密,晶面为(111)、(220)、(200).该铸镍铁合金矫顽力最小为2.95×10-2 A/m,表现出较强的顺磁性.剩磁力随着铸层铁含量的增大呈下降趋势,饱和磁化强度为IJ85合金的10%,具有优良的电磁性能.可以用于制造微型磁执行器与传感器元件.     

超声电沉积镍/纳米碳化硅复合镀层组织结构研究

采用超声电沉积方法在20钢基体上制备了镍／纳米碳化硅的复合镀层。通过扫描电镜(SEM)观察了镀层的表面形貌和显微组织，用能谱仪(EDS)对镀层中特定区域进行了显微组织成分分析，使用X射线衍射仪检测了镀层的微观结构。结果表明：通过合适的超声电沉积工艺，得到的镀层中SiC纳米粒子含量较高，且分散均匀，没有出现团聚现象；同时镀层中的镍晶粒得到了细化，取向也由择尤取向趋于随机取向。     

向您介绍高校技术转让项目

化学镀镍合金技术化学镀镍合金是利用还原剂在镀液中将镍离子催化还原,在镀件表面沉积镍合金镀层的表面镀覆技术。其工艺特点:①镀覆过程不需外电源驱动。②镀液无毒,废液易于处理。③均镀能力强,形状复杂的零件可获得均匀的镀层,镀层厚度差控制在1～3μm 内,设定的镀层厚度可控制在±5～10μm 内。④孔隙率小。⑤镀速可调整。⑥镀液再生性好。⑦适用基材     

TiC纳米颗粒复合镀层组织性能分析及与镍镀层的比较

本文针对磨损失效汽缸体进行电刷镀再制造研究。用最佳工艺参数分别进行镍镀层和分别添加3g/l,6g/l,9g/l Ti C纳米粉的纳米复合镀层的电刷镀试验,对比镍镀层和不同含量Ti C纳米粉的复合镀层的性能,进而得出一种综合性能最佳的镀层,即为工艺参数如刷镀电压12V,阳极速率20m/min,刷镀时间15min,Ti C纳米粉含量为6g/l的纳米复合镀层。     

化学复合镀Ni-P-TiO_2工艺及性能研究

研究了化学复合镀 Ni- P- Ti O2 工艺中 Ti O2 含量、表面活性剂种类和含量及搅拌方式等因素对镀层中 Ti O2 含量及镀速的影响 ,并对镀层的表面形貌和性能进行测定。结果表明 :用最佳工艺所得镀层均匀、光亮 ,对大肠杆菌的杀菌率为 97.86% ,对金黄色葡萄球菌的杀菌率为96.2 3% ,镀层附着性能好 ,当镀层厚度达到 2 0 μm时 ,耐盐雾性能可达 1 0级     

Ni-La2O3纳米复合镀层制备工艺研究

将La2O3纳米颗粒添加到氨基磺酸镍镀液中采用电沉积方法制备Ni-La2O3纳米复合镀层，研究了多种因素对复合镀层中La2O3含量的影响，分析了复合镀层的表面形貌和显微硬度。结果表明：试验条件下最佳工艺为电流密度2A／dm^2、镀液温度50℃、搅拌速度800r／min、镀液中La2O3含量30g／L；与纯镍镀层相比，复合镀层表面平整光滑、组织致密均匀；其显微硬度也高于纯镍镀层，并随着复合镀层中La2O3含量的增加而升高。     

酸性盐雾环境对典型金属材料的腐蚀研究

对典型金属材料H62、GCr15、316L在酸性盐雾环境中的腐蚀进行研究。镀金厚度影响H62的耐酸性盐雾腐蚀能力,铜基1.26μm镀金层表面存在微孔,使中间镍镀层暴露在酸性盐雾环境中,吸附在微孔处的酸性液膜对中间镍镀层进行腐蚀,随着腐蚀的发展,最终对基材造成腐蚀;铜基3.17μm镀金层杜绝了中间镍镀层和基材与外界的接触,从而避免了材料腐蚀。铬Cr含量影响合金钢的耐腐蚀能力,GCr15中Cr含量较低,形成的氧化铬钝化膜无法完全覆盖基材表面,使Fe与酸性液膜中的O₂反应,造成材料腐蚀;316L中Cr含量较高,形成的氧化铬钝化膜可以有效覆盖基材表面,避免材料腐蚀。     

以次亚磷酸钠为还原剂的ABS塑料室温镍-磷化学镀工艺

为提高ABS塑料镍-磷镀层的表面质量,研究了以次亚磷酸钠为还原剂的室温碱性化学镀工艺,并对工艺进行了优化,对优化工艺制备的镀层性能进行了表征.结果表明:优化的镀液配方为28 g·L-1硫酸镍,27 g·L-1次亚磷酸钠,50 g·L-1柠檬酸钠,50 g·L-1氯化铵,0.002 5 g·L-2十二烷基苯磺酸钠,pH值8.5～9,温度25~30℃;镀层厚度达到10 μm时,其平整度、附着力较好,目测光亮度可达1级,硬度较低,方块电阻小于10 μΩ·□-1.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.