热处理对铝合金表面化学镀镍镀层性能影响

针对铝合金表面化学镀镍层结合力和耐蚀性差的问题,采用热处理方法提高镀层结合力和耐蚀性.高低温试验后用划痕法检测结合力强度,运用盐雾试验检测耐蚀性.通过对比试验和结果分析表明：热处理温度和时间对镀层性能存在交互作用;经过150℃、1.5h热处理,镀层与基体结合力最好,80h高、低温试验（高温105℃,低温-55℃）后,镀层结合力强度为48.7MPa;镀层经过150℃、1h热处理,镀层耐蚀性最好,96h盐雾试验后,外观无白斑、起泡、脱皮等腐蚀现象.     

高强度钢中温化学镀镍磷合金工艺技术研究

针对兵器某飞行智能产品中所用高强度钢滑动零件化学镀镍磷合金难施镀及镀层性能差的特点,从材料特性与化学动力学的相互关系出发,运用正交试验和均匀试验,获得了适合于高强度钢的中温化学镀镍磷合金工艺技术,并顺应“清洁生产”的发展趋势。通过研究镀液主盐含量及比值、络合剂、加速剂、稳定剂、温度、pH值等因素对沉积速度、镀层耐蚀性与耐磨性的影响,解决高强度钢零件化学镀镍磷合金难施镀、镀层易起皮、结合力差、镀层耐蚀性与耐磨性匹配性差等问题。靶试及库存结果表明：该工艺技术获得的镀层性能良好,耐蚀性与耐磨性实现了最佳匹配,可为兵器装备高硬材料化学镀提供技术参考,尤其在复杂多变的环境下服役的智能化产品滑动零部件上,具有广阔的应用前景。     

腐蚀性气体对金属镀层的影响

金属镀层耐腐蚀能力一般通过盐雾试验进行验证,大多数情况下忽略了腐蚀性气体的影响。随着产品使用时间的增加,镀层表面光泽会变暗,甚至出现深色斑点。电接触元器件表面长时间腐蚀后形成的腐蚀产物厚度不均匀,接触电阻发生变化,最终造成电接触故障,影响产品使用寿命。显然,气体腐蚀在产品外观以及电气性能上都造成了一定的影响。通过模拟气体腐蚀环境,验证铜镀银、铜镀锡、铜镀镍材料在一定浓度的NO2、SO2、Cl2、H2S气体环境下外观、镀层厚度和接触电阻的变化。试验结果表明,腐蚀性气体对外观影响从大到小为铜镀银、铜镀锡、铜镀镍,对接触电阻影响最大的是铜镀镍,铜镀银和铜镀锡无明显变化。     

低温化学镀镍工艺及镀层性能的研究

讨论了镀液主要组分及工艺条件对低温化学镀镍沉积速度的影响，对低温化学镀镍镀层的硬度、结合力、孔隙率及耐蚀性能进行试验，并利用电子显微分析方法，研究了镀层的微观形貌。研究结果显示，不同的工艺条件对镀层的各项性能均有影响，因此，在实际生产中，必须严格控制施镀的工艺条件，以确保镀层的各项性能均达到要求。     

TL全光亮化学镀镍磷合金工艺

研究了全光亮化学镀镍层的主要技术条件,光亮剂的选择,被镀件表面状态对镀层光亮度的影响,合理施镀工艺条件。结果表明:该工艺可获得全光亮镀层,孔隙率低,耐蚀性能好。同时,对镀液的沉积速度、稳定性、装载量、pH值及施镀温度对镀层光亮度的影响均进行了试验。完成TL-013、TL-014两种全光亮化学镀镍磷合金浓缩液配方和完善的施镀工艺。     

灰铸铁气缸套表面Ni-P涂层的组织结构及抗穴蚀性研究

研究了贝氏体基体灰铸铁基体气缸套上化学镀镍的基本处理工艺,并对Ni-P镀层物相结构、表面形貌及耐蚀性进行分析。结果表明:化学镀镍磷层形貌为胞状结构,表面平整光滑;经热处理后,镀层结构由非晶态向晶态转变,硬度值也随之增加,在200℃时镀层发生结构驰豫,在300℃时镀层结构完全晶化。穴蚀试验后,300℃保温1h得到的化学镀镍层失重比率最小,抗穴蚀能力最强。     

高稳定性化学镀镍磷合金工艺研究

运用扫描电子显微镜研究了含稀土元素镀液镀层初期沉积形貌及组织结构，探讨了稀土离子对化学镀镍磷的影响，并通过正交试验对镀层耐腐蚀性等性能进行了测试比较，取得了稀土复合镀镍磷合金的最佳配方。研究表明：在原有的化学镀技术中引入稀土元素，晶粒细化，镀液寿命延长，得到的整体非晶态镀层耐腐蚀性提高。     

化学镀镍新溶液应用研究

以化学镀镍反应机理为依据,针对中磷环保化学镍1123,就其添加方式,对镀层结合力、耐蚀性、氢脆性、硬度等进行试验,对比自配化学镍溶液,确定了使用中磷环保化学镍1123进行满足AMS2404标准的化学镀镍生产,并通过试验确定了一种新的溶液补充添加方式。     

高性能煤化工浆料输出用硬质合金喷嘴的制备试验

研究了采用高纯石墨模具和添加镀镍短枝碳纤维对硬质合金性能的影响。通过对试样进行摩擦试验和盐雾试验来分析高纯石墨模具和镀镍短枝碳纤维对硬质合金摩擦性能和防腐性能的影响。分析表明:采用高纯石墨模具可以有效提高硬质合金的摩擦性能,镀镍短枝碳纤维可以有效提高硬质合金喷嘴的摩擦性能和防腐性能。为应用在煤化工行业的硬质合金喷嘴鉴定了理论和实践基础,开拓了新的思路。     

化学镀的表面硬化处理

利用化学镀镍获得硬质镀层最近正在迅速发展,其理由是化学镀镍层有良好的抗蚀性、耐磨性,同以往的硬质镀铬层比较,此法所得镀层均匀性好,操作方便。 1.镀镍-磷合金以次磷酸盐为还原剂的化学镀镍层含磷4～12％,呈现非常细的镀层,在镍镀层中磷呈过饱和状态。由于经过大约280℃的热处理,镍基质发生再结晶,温度再高形成镍-磷化合物     

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.