钯电镀工艺

由于钯（Pd）镀层具有优良的耐蚀性、耐磨性和电性能等,已经应用于电器接点、连接器、IC引线架和印制板（PCB）等电子电器零件中,还由于Pd镀层比金镀层价廉,因而希望用Pd镀层取代传统使用的金镀层。迄今为止,已有许多专利文献介绍了获得Pd镀层的Pd电镀液,但是这些Pd镀液存在的问题有：①由于Pd镀层内应力较高,因而难以多镀层中获得延展性优良的厚Pd镀层;②由于Pd镀层在可焊性、耐热性和附着性等方面存在问题,难以满足电子零件对焊料镀层的要求,近年来随着电子电器的高性能化和小型化,应用于电器中的PCB和IC引线架等电子零件的线宽和间距正在逐年微细化,因此要求电子零件具有更高的物理性能,优良的焊料湿润性和加热后的易焊性,迫切需求改善Pd镀液乃至Pd镀层的性能。本文就获得耐热性、焊料湿润性优良的Pd电镀工艺加以叙述。     

氢在钯纳米晶薄膜中的扩散

采用电刷镀工艺制备了厚度＜1μm的钯膜。AFM和SEM观测表明钯膜由半球型的纳米晶簇构成,晶簇尺寸在20－30mm之间;在薄膜中没有发现裂纹和气孔。利用电化学剥离方法测定了氢在α薄膜的扩散系数（298－ 328K）。氢的扩散行为符合Arrhenius定律。扩散系数比相同温度下体材料的扩散系数低1个数量级,表明晶界阻碍了氢的扩散。     

Al2O3/Ni纳米复合电刷镀技术应用于失效凸轮轴再制造的实验研究

目的将Al_2O_3/Ni纳米复合电刷镀技术应用到失效凸轮轴修复,使失效凸轮轴得以再制造利用。方法在快速镍镀液中加入Al_2O_3纳米颗粒和分散剂柠檬酸三铵、十六烷基三甲基溴化铵形成复合镀液,将复合镀液放在恒温磁力搅拌器上加热并搅拌,使复合镀液温度达到50℃且纳米Al_2O_3悬浮稳定。利用电刷镀技术将复合镀液镀于与凸轮轴材质相同的45#钢板表面,通过硬度测试,分别评价纳米Al_2O_3质量浓度、刷镀电压对复合镀层硬度的影响。结果复合镀层的硬度大于45#钢,且硬度随刷镀电压、纳米Al_2O_3质量浓度的增加而增加。当刷镀电压大于10 V后,硬度随纳米Al_2O_3质量浓度的增加而减小。复合镀层表面裂纹随纳米Al_2O_3质量浓度、刷镀电压的增加而增多,纳米Al_2O_3的质量浓度越低,电压变化对复合镀层表面硬度的影响越大。相对纳米Al_2O_3质量浓度,电压对复合镀层表面硬度的影响更大。结论用Al_2O_3/Ni纳米复合电刷镀技术修复失效凸轮轴可提高凸轮轴表面硬度,使其得以再制造利用。为提高凸轮轴表面质量,避免出现表面疏松、焦糊等缺陷影响表面硬度,应开发自动化纳米复合电刷镀设备及采用不同镀层交替叠加方式刷镀。     

涂覆速度和热处理对直接镀Pd键合Cu线性能的影响

利用扫描电镜、强度测试仪研究了键合铜线无卤直接镀钯工艺及镀钯键合铜线性能,分析了涂覆速度、热处理及张力对直接镀钯铜线拉断力、伸长率和表面质量的影响。结果表明：无卤直接镀钯工艺可获得镀层均匀的镀钯键合铜线;涂覆速度为80～90 m/min时,镀钯铜线具有适当的厚度和良好的表面质量;随热处理温度提高,直接镀钯铜线拉断力降低,伸长率增加;当热处理温度为450 ℃时,表面钯原子扩散速率加快,线材强度增加,其表面颜色由金属钯色变为灰铜色;当热处理温度为470 ℃时,镀钯铜线晶粒粗大,力学性能降低;热处理过程中张力小于0.020 N导致线材表面机械损伤,张力大于0.035 N时造成线材表面波浪纹缺陷。当热处理温度为430 ℃,张力为0.025～0.030 N时,0.020 mm镀钯铜线具有优异的性能。     

镀钯技术及工艺研究

为了适应现代电子、光学及装饰等领域的需要,采用正交试验法研究了镀钯新技术及工艺,研究了镀液成分和工艺条件对镀层的影响.概述了镀钯液的配制和维护,并介绍了镀钯过程中的注意事项.利用本工艺电镀能得到性能优良的钯镀层,如外观白亮、反光率高、接触电阻小、硬度高、耐磨、耐蚀等优点.     

用微计算机控制刷镀的软硬件设计

实践证明，刷镀时的工作电压、镀笔与工件被镀表面的相对运动速度和镀液温度等主要工艺参数，对刷镀层质量影响很大。为了获得高质量刷镀表面，需要做好以下控制。     

刷镀电压对电刷镀Ni-W(D)合金镀层性能的影响

通过热震试验、磨损试验、金相观察等方法研究了刷镀电压对Ni-W(D)合金镀层结合性、耐磨性以及显微硬度和微观组织的影响。研究结果表明，刷镀电压太高或太低镀层性能都会恶化，刷镀电压为12V时镀层与基体的结合性最好，镀层的晶粒细小、具有较大的显微硬度，其耐磨性最好。     

碳纳米管铅锡复合减摩镀层的内应力研究

采用复合电沉积方法在紫铜片上制备碳纳米管铅锡合金复合减摩镀层;用阴极弯曲法研究了电流密度和镀液温度对碳纳米管铅锡复合镀层内应力的影响;在不同碳纳米管浓度的镀液中制备了复合镀层的试样,用X射线衍射法测定了各复合镀层的内应力.结果表明,碳纳米管铅锡合金复合镀层的内应力随电流密度的增加而升高,但随镀液温度的升高而降低.保证电流密度和镀液温度不变,碳纳米管的含量为2g/L,复合镀层的内应力降至最低;碳纳米管在镀层中的弥散分布起到了应力传递作用,减少了应力集中而产生的微裂纹.     

铸铝上刷镀Ni-P合金工艺研究

铸铝箱体件很容易因磨损而报废,对磨损后的铸铝箱体件采用Ni-P合金刷镀再修复,可恢复铸铝箱体件的原始配合尺寸,提高其使用寿命.研究了刷镀铸铝箱体零件的Ni-P合金刷镀液、特殊预处理液的配方及电刷镀工艺.特殊预处理工序有效地防止了铸铝表面的再氧化,使后续刷镀层结合力好,避免了刷镀层易剥落的弊端.铸铝刷镀过镀层采用高堆积碱铜,工作层采用Ni-P舍金.刷镀层硬度高(可达613HV),耐磨性好.该工艺方法解决了铸铝箱体件磨损后修复难等问题.     

超疏水不锈钢网双面复合电刷镀制备法及其油水分离应用

目的 采用双面复合电刷镀法制备一种超疏水不锈钢网,并实现油水分离。方法 搭建双面复合电刷镀试验装置,将不锈钢网依次进行预处理、刷镀过渡镀层、刷镀工作镀层和低表面能改性处理,得到超疏水性能良好的不锈钢网。研究刷镀电压、刷镀时间、刷镀速度和刷镀温度等参数对不锈钢网微结构和润湿性的影响。借助光学接触角测量仪、扫描电子显微镜、X射线衍射仪和傅里叶变换红外光谱仪等分析测试设备,对制备的不锈钢网的表面润湿性、微观形貌、元素组成和油水分离性能等进行测试分析。结果 双面复合电刷镀工艺能够在不锈钢网表面形成均匀分布的花椰菜状微/纳米级粗糙结构,镀层的主要成分为镍,并含有微量纳米二氧化硅。在刷镀液温度为25℃、刷镀速度为8 m/min条件下,以15 V的刷镀电压刷镀3 min,超疏水不锈钢网的接触角达到159°,滚动角为7°。制备的不锈钢网具有优异的油水分离性能,对正己烷、二氯甲烷等多种油水混合物的分离效率达到95%以上,且分离纯度较高。结论 采用双面复合电刷镀工艺可简单快速地获得双面超疏水不锈钢网,制备的超疏水不锈钢网能高效地分离多种油水混合物,在海洋溢油清理等领域有良好的应用前景。     

钛合金表面技术的进展

钛合金具有抗腐蚀能力强、强度高、密度低、中温性能稳定等一系列的特征，但其所固有的一些缺点限制了它的应用，例如对粘着磨损非常敏感、容易氧化，对聚合物，金属及陶瓷涂层附着力差等。为克服这些缺点采取了相应的对策与手段，着重指出Ag,Cd镀层可用于钛合金在低温下的耐磨防护；Co CrO3复合镀层及阳极氧化＋干膜润滑剂等可用于钛合金在中温条件下的耐磨防护。随着钛合金使用温度的提高，TixAlyN涂覆层则代表了钛合金耐磨防护的发展方向。     

High cycle fatigue behaviour of Ti–6Al–4V alloy at elevated temperatures

High cycle fatigue behaviour of Ti–6Al–4V alloy was studied at 623 K and 723 K. Fatigue strength decreased at elevated temperatures compared with at ambient temperature. In the short life regime, fatigue strength was lower at 723 K than at 623 K, but in the long life regime it was nearly the same at both temperatures. At elevated temperatures, cracks were generated earlier at applied stresses below the fatigue limit at ambient temperature, indicating lowered crack initiation resistance. Small cracks grew faster at elevated temperatures than at ambient temperature, which became more noticeable with increasing temperature. After allowing for the elastic modulus, small cracks still grew faster at elevated temperatures.     

Wear mechanism of electrodeposited amorphous Ni-Fe-P alloys

1　INTRODUCTIONAmorphousalloysarecharacterizedbyhighwearandcorrosionresistance ,togetherwithmanyspecificphysicalproperties[1,2 ] .Theyhavebeenusedasfunc tionalmaterialsinmanyfieldsextensively .Theamor phousNi Palloyhasbeenappliedtoautomobile[3] ,aircraft,computer ,electronics ,food processing ,petroleum ,andsoon[4 ] .Electrodepositionorelectrolessplatingisoneofthemostsimple ,convenientandeconomicmethodstoobtainvariousamorphousalloys .Themostattractiveamorphousalloysconsistoftheelementsof…     

金刚石表面镀钛及其在胎体中结合状态的研究

采用真空蒸发-扩散镀的方法在金刚石表面镀钛,研究了镀覆温度和保温时间对金刚石表面形貌、镀层厚度、镀层物相的影响规律,分析了镀钛金刚石的抗氧化性能,研究了镀钛金刚石及其在铁基胎体中的结合状态。结果表明:在低温下（680℃）镀覆时,金刚石表面开始出现TiC;随镀覆温度升高或保温时间延长,镀层逐渐致密并增厚,在720℃镀覆时出现Ti沉积,在820℃镀覆时由于应力原因产生裂纹并导致镀层的破坏;镀层可隔绝金刚石与氧的直接接触,大幅度延缓氧对金刚石的侵蚀作用;镀钛后金刚石在胎体中可实现牢固的冶金键合。      

Wear behavior of iron boride coating on AISI 4140

A new paste technique was established for making boronising coatings. This method gave iron boride coatings a unique wear and tear property something that was tested as a microstructural feature. The coats were acquired from obtained by transmission of boron molecules from ferrobor concentrates to steel surface. Boronising parameters were applied at temperatures between 1023 and 1248 K temperatures at time range 2–8 h. This process led to enhancement in the coat layer, thickness and microstructure. To assess the durability and strength of the resultant element, a tribometer in block-on-ring configuration was used with a pairing of 20, 40 and 60 Newton’s at sliding speeds of 0.2–1.85 ms^–1. It was found that, the coats made at temperatures of 1173–1223 K for 8 h lasted as long as the coat existed. Once they coat got off, residues of the same brought body abrasion. If time taken to boronize was reduced to 4–6 h at temperatures of between 1073 and 1173 K, then wear of the coat became oxidative with no trace of cracks.     

变形温度对核电用锆包壳管表面Cr涂层开裂行为的影响

Cr涂层能够有效提高核电反应堆锆包壳管的事故容错能力，但在高温下其内部可能会萌生裂纹导致涂层开裂失效，现有Cr涂层开裂行为研究多针对常温，因此研究不同温度下Cr涂层的开裂行为对于其应用具有重要的理论和工程价值。采用多弧离子镀技术在N36锆合金包壳管外表面制备厚度为14μm左右的Cr涂层，采用WDW-100C万能试验机对涂层管分别进行室温（25℃）与高温（100、200、300、400℃）拉伸试验，并通过超景深显微镜和扫描电镜（SEM）观察涂层的裂纹表面与截面形貌，对Cr涂层在不同温度下的开裂行为与开裂机理进行研究。结果表明，随着温度升高，涂层管的屈服强度从（400±5）MPa下降到（150±5）MPa，涂层管的总体塑性变化不大；室温下裂纹萌生于涂层内部，其开裂方式为脆性沿晶断裂；100℃时涂层开裂方式不变，但表面裂纹数量减少，裂纹尖端出现钝化，由V字形转变为U字形；随着温度进一步升高，涂层的塑性变形能力提高，其表面呈流线形塑性变形；200℃及以上温度下，涂层表面无明显开裂，仅出现少量微裂纹，塑性的升高导致拉伸过程中涂层的变形量与基体存在差异，裂纹开始萌生于界面处，其断裂方式也由脆性断裂...     

阳极温度分布对耦合电弧AA-TIG高速焊焊缝成形的影响

针对耦合AA-TIG电弧采用热电偶法测量了阳极温度分布.在垂直于主钨极和辅助钨极连线方向上,随着距连线的距离增大,耦合AA-TIG电弧的阳极温度逐渐降低,在主钨极位置处的温度最高,辅助钨极位置处次之,钨极中心点位置处最低.在主钨极和辅助钨极连线方向上,随着钨极间距增大,耦合AA-TIG电弧中心区域温度逐渐降低,外围区域温度逐渐增高,由单峰分布向双峰分布过渡.当钨极间距较大时,耦合AA-TIG电弧热源在主钨极和辅助钨极连线方向上被拉长,有利于消除高速焊时的咬边和驼峰焊道等缺陷.     

A novel electrolyte for the high speed electrodeposition of bright pure tin at elevated temperatures

A new tin electroplating process capable of producing fully bright, pure tin deposits from an electrolyte operated at temperatures of up to 50°C has been developed. Unlike conventional bright tin deposits, the tin deposit from the new process has an increased grain size and low carbon content. In addition, the deposit demonstrates excellent ductility, solderability, and low tendency for whisker growth. Production trials conducted by various industries have proven that the new pure tin deposit is suitable for connector applications, as well as for corrosion protection and decorative uses. In this article, the characteristics of the tin electrolyte and the bright tin deposit are described.Electrodeposition of bright tin, characterized by its silvery-white decorative appearance, excellent solderabilty, conductivity, good corrosion and tarnish resistance, and non-toxic nature, has been widely used in the electronic industry and protective-decorative applications. The industrial importance of tin electrodeposition has been markedly extended with the introduction of lead-free solder in the electronic marketplace. However, certain drawbacks of commonly used bright tin plating processes have limited the acceptance of electrodeposited bright tin. The operation and control of bright tin plating solutions is more difficult compared to that of matte tin processes, since the additive system of conventional bright tin electrolytes usually contains many volatile organic components that act as brightening agents. Because of the volatile nature of the organic brightening agents, a cooling system is usually required in conventional bright tin plating baths, in order to maintain the bath temperature between 20 to 25°C where most brightening agents are effective. For high-speed plating, the use of a cooling system becomes essential since the bath temperature naturally rises rapidly during plating. A key concern with the use of bright tin in certain applications is the relatively low ductility often associated with bright deposits and the reportedly higher tendency towards tin whisker growth compared to matte deposits. For demanding automotive applications, where the use of bright tin-lead has been permitted for a limited period of time, continuing efforts are being made by both the electronics industry and suppliers of plating chemistry to replace bright tin-lead with bright pure tin. Tin whisker performance has become one of the most critical characteristics in qualification of any bright pure tin plating process for use in the electronics industry.The newly developed plating bath, SOLDERON? BHT-350 bright tin, has been designed to be operated at temperatures between room temperature and 50°C, while producing ductile, bright deposits with low whisker growth tendency. Production trials conducted by different industries have demonstrated that the new process is able to produce bright tin deposits under high speed reel-to-reel plating conditions, and the simple additive system facilitates automatic or manual dosing during operation. The resulting bright tin deposits are suitable for connectors, contacts, wire and other items requiring a bright tin finish. In this article, the characteristics of the electrolyte and the properties of the bright tin deposit, including microstructure, carbon content, ductility, texture, solderability and whisker performance are described in detail.     

High speed nickel sulphamate plating of connector strip

High deposition rates and low internal stress of the deposit from nickel sulphamate electrolytes without the use of addition agents, offset the greater cost compared to the conventional Watts nickel solution. Chloride or bromide ions can be added to the electrolyte to improve conductivity and aid dissolution of the nickel anode with little to no anode polarisation. Anodes can be either sulphur activated or pure nickel forms. These choices have been studied for a high speed nickel sulphamate solution used in reel-to-reel plating of connector strip for the electronics industry. The results provide guidance about the influence of halides and anode form on maintaining consistently low tensile stress, while presenting the opportunity for power savings and reducing the need for regular anode cleaning to remove insoluble residue from sulphur activated nickel. Over 6 years of industrial practice, pure electrolytic nickel anodes with nickel chloride added to the electrolyte have provided cost effective operating conditions combined with satisfactory deposit properties in more than 30 reel-to-reel plating lines in Asia.     

海水温度对金属氧化物阳极强化电解失效行为影响

采用热分解法在钛基体上制备钌铱锡金属氧化物阳极,通过SEM、EDX、循环伏安、电化学阻抗谱及强化电解寿命试验等测试方法,探求不同海水温度对于钌铱锡金属氧化物阳极强化电解失效行为的影响规律。结果表明：在5~20 ℃海水温度条件下,阳极寿命短,失效阳极的中心区域存在少量残余涂层,呈现龟裂状形貌,而边缘地带Ti基体基本暴露,涂层发生局部电化学溶解或剥落;当海水电解温度为40 ℃时,阳极寿命较长,阳极涂层发生均匀电化学溶解。另外,随着海水温度的升高,阳极电化学活性表面积增大,稳定性逐渐提高。5~20 ℃条件下阳极失效主要是由于Ru组元的选择性溶解和涂层局部剥落导致,而40 ℃条件下涂层也发生电化学溶解,但TiO2钝化膜的形成是引起阳极失效的主要原因