电镀与环保

电镀Cu—Sn合金工艺研究进展，化学镀镍废液处理方法的现状及展望，纤维微粒在电解液中运动方式的模拟，稀土对电沉积Ni—Fe-P—RE合金镀层的影响     

Fe—P非晶态合金电镀层性能研究

在以氯气化亚铁和次磷酸钠为主盐的电解液中获得含Ｐ量Ｐｐ＝１０％～１４％的Ｆｅ－Ｐ非晶态合金镀层，测量了镀层的差热分析同线和经不同热处理后镀层的显微硬度，据此分析了加热对镀层结构的影响，直流电镀所得Ｆｅ－Ｐ非晶合金镀层很脆，使用交直流迭加电流进行电镀可以使镀导脆性大小减小。     

二元锡铅合金电镀工艺实践

锡和铅都是低熔点金属,锡的熔点231.9℃,铅的熔点327.4℃。锡铅二元合金,是低熔点合金,锡铅合金镀层是低熔点功能性二元合金镀层,锡铅合金镀层在空气中有良好的化学稳定性,可焊性能优于锡镀层,也不会象锡镀层那样容易在其表面形成针状晶须,所以锡铅二元合金电镀广泛应用于电子元器件工业领域。 锡铅合金镀层的结晶较锡或铅单金属的结晶都细致,并具有抗蚀性等多种优异性能,二元合金镀层中锡铅含量比例不同,锡铅二元合金镀层的用途有所区别。如含锡4％～10％的锡铅合金镀层可作为钢铁制件的防腐层用于特定的环境中,含锡6％～10％的锡铅合金镀层,由于防蚀和减摩作用优良,广泛用于高速发动机滑动轴承摩擦面的减磨镀层。含锡40％～60％的铅锡合金镀层有熔点低、焊接性能优良等性能,大量应用于电子元器件工业,本文就低熔铅锡二元合金电镀实践提些肤浅看法,与电镀界同行共商。     

光电子器件外壳脉冲电镀镍钴合金工艺及其耐蚀性

目的开发一种脉冲电镀镍钴合金工艺,并研究其镀层的耐腐蚀性能,以期将其应用于光电子器件外壳电镀领域。方法采用脉冲电镀的方式获得电镀镍钴合金镀层,通过腐蚀失重试验、极化曲线测试以及电化学阻抗谱测试等方法考察镀层的耐腐蚀性能,通过场发射扫描电子显微镜、能谱仪和X射线衍射仪等设备对镀层的表面微观形貌、成分和晶体结构进行了表征,并与传统的电镀氨基磺酸镍工艺进行了抗腐蚀性能的比较。在耐腐蚀性能最优的工艺条件下,对公司某型号光电子器件外壳进行了镍钴合金电镀,并对产品的镀层进行一系列考核。结果随着Co含量的增加,脉冲电镀镍钴合金镀层的结晶更均匀致密,晶粒、镀层孔隙更小。在3.5%NaCl溶液中,随着Co含量的增加,脉冲电镀镍钴合金镀层的自腐蚀电位正移,自腐蚀电流密度减小,电荷转移电阻增加。Co含量25%的脉冲电镀镍钴合金镀层的自腐蚀电位和自腐蚀电流密度分别为-331 mV和2.26μA/cm~2,电荷转移电阻是212.62 kΩ。产品的镀层质量、引线涂敷强度、引线疲劳等考核均满足相关标准要求。结论脉冲电镀镍钴合金镀层的耐蚀性随着Co含量的增加而增强。在3.5%的NaCl溶液中,Ni-Co(25%)的镀层自腐蚀电流仅是Ni镀层的44%。开发的脉冲电镀镍钴合金工艺可以应用于光电子器件外壳电镀领域。     

电镀用锌镍合金阳极的研制及应用

用铸造方法 ,研制出适合电镀用可溶性锌镍合金阳极 ,即Zn 10 %Ni合金。该锌镍合金具有两相组织 ,不仅解决了以往电镀工艺复杂、镀层成分和性能不稳等缺点 ,而且电镀出了比锌镀层氢脆小、硬度高、防护性好的合金镀层     

Ce3+对Zn-Ni合金镀层耐蚀性能的影响

在电镀液中添加铈盐,于Q235钢表面电镀Zn-Ni合金,考察了Ce3+添加量对Zn-Ni合金镀层耐蚀性能的影响.通过稳态阳极极化曲线、塔菲尔极化曲线和交流阻抗谱,研究了镀层在30℃3.5％NaCl溶液中的腐蚀行为;同时对比了Zn-Ni合金镀层在腐蚀前后的微观结构和表观形貌.结果表明:加入铈盐,不改变Zn-Ni合金镀层的晶面择优取向,但会改变各晶面的织构系数;添加铈盐后,Zn-Ni合金镀层的致钝电流密度和维钝电流密度明显降低,极化阻抗明显增大;当镀液中添加0.80 g/L铈盐时,镀层结晶粒度明显变小且致密,使得耐蚀性能显著增加.     

烧结钕铁硼磁体表面Zn-Co合金镀层制备工艺与耐蚀性能

采用氯化物镀液体系在钕铁硼磁体表面制备Zn-Co合金镀层,优化了Zn-Co合金镀层制备过程中的电镀工艺参数(镀液pH值、镀液温度、电流密度以及添加剂浓度),通过中性盐雾试验(NSS)、扫描电子显微镜(SEM)和动电位极化曲线,系统研究了Zn-Co合金镀层的显微组织及耐蚀性能。结果表明:烧结钕铁硼电镀Zn-Co合金镀层的最佳电镀工艺参数为:添加剂浓度为15 mL/L,pH值为4,电镀温度为25℃,电流密度为1 A/dm~2。在最佳工艺条件下制备的Zn-Co合金镀层经钝化后其耐中性盐雾时间可达120 h。合金镀层结构致密,有效填补了钕铁硼磁体的固有缺陷,为后期钝化形成致密钝化膜提供了材料基底基础。钝化后的Zn-Co合金镀层表面平整光亮,动电位极化曲线测试表明,相比Zn镀层,钝化后的Zn-Co合金镀层的自腐蚀电流密度下降了一个数量级,表明Zn-Co合金镀层钝化后具有更加优异的耐腐蚀性能。     

无氰碱性电镀工艺对黄铜微观结构的影响

在碱性条件下,以硫酸盐为基础溶液,酒石酸钾钠和柠檬酸钠为络合剂,在A3钢表面电镀黄铜合金薄膜。用XRD研究在不同温度、不同电流密度条件下及加入添加剂γ-APS的黄铜合金镀层的微观结构。用SEM和EDS研究在不同电镀时间下黄铜合金镀层的表面形貌和组成。结果表明,电流密度对镀层微观结构影响最为明显,在最佳电镀工艺条件温度为35℃,电镀时间8 min,电流密度为15 mA/cm2时电镀出的Cu-Zn黄铜合金,镀层结晶晶粒均匀,镀层中Cu：Zn质量比为64：36。加入添加剂-γAPS后得到的黄铜合金镀层结晶晶粒更加均匀致密且呈现金黄色。     

无氰碱性电镀工艺对黄铜微观结构的影响

在碱性条件下,以硫酸盐为基础溶液,酒石酸钾钠和柠檬酸钠为络合剂,在A3钢表面电镀黄铜合金薄膜。用XRD研究在不同温度、不同电流密度条件下及加入添加剂γ-APS的黄铜合金镀层的微观结构。用SEM和EDS研究在不同电镀时间下黄铜合金镀层的表面形貌和组成。结果表明,电流密度对镀层微观结构影响最为明显,在最佳电镀工艺条件温度为35℃、电镀时间8 min、电流密度为15 mA/cm2时电镀出的Cu-Zn黄铜合金,镀层结晶晶粒均匀,镀层中Cu∶Zn质量比为64∶36。加入添加剂-γAPS后得到的黄铜合金镀层结晶晶粒更加均匀致密且呈现金黄色。     

锌镍合金电镀技术的研究

研究了采用锌镍合金为阳极进行电镀时,工艺条件对锌镍合金镀层镍含量的影响,寻找出耐蚀性是镀锌层５倍以上Ｚｎ－Ｎｉ（１３％）合金镀层电镀的工艺条件。对镀液进行了连续电镀试验,电镀后镀液中金属离子浓度波动小,采用合金阳极进行电镀可以基本维持金属离子浓度的稳定,还应用多种测试方法,检测了镀层的结合力。     

Fe-P非晶合金的电沉积行为及热处理对其结构与性能的影响

在以柠檬酸三钠为络合剂的酸性镀液中电沉积Fe-P非晶合金,采用差示扫描量热(DSC)、X射线衍射(XRD)和扫描电镜(SEM)研究该合金镀层的晶化行为和表面微观形貌。结果表明:镀液中加入络合剂,且随着pH值升高和温度降低时,Fe-P非晶合金共沉积的阴极极化增大。镀态Fe-P合金为非晶态结构,于330.5℃时开始晶化;383.6℃时,α-Fe(P)固溶体大量晶化析出;472.5℃时,Fe3P(I-4)相大量脱溶析出。且随着热处理温度升高,合金镀层的耐蚀性能和硬度先增加后下降,450℃热处理所得镀层的耐蚀性能最佳且硬度最大;在400℃以下时,镀膜具有良好的抗热氧化能力,当温度在400℃以上时,抗氧化能力迅速下降。     

Synergistic Effect of Mo,W, Mn and Cr on the Passivation Behavior of a Fe-Based Amorphous Alloy Coating

In this work, the electrochemical behaviors of SAM2 X5 Fe-based amorphous alloy coating and hard chromium coating were comparatively studied in 3.5 wt% Na Cl solution. In comparison with the hard chromium coating, the SAM2 X5 coating exhibited a wider and stable passive region with lower passive current density in the potentiodynamic polarization and showed a considerably lower current density at different anodic potentials in the potentiostatic polarization. In order to understand the passivation mechanism of the Fe-based amorphous coating, the components of the passive films formed at various polarization potentials were examined by X-ray photoelectron spectroscopy. The synergistic effect of Mo, W, Mn and Cr in the passive films was systemically analyzed. It has been revealed that Mo and W facilitate the formation of compact and stable Cr_2O_3 passive film at lower potentials, and the substantial enrichment of Mn in the passive film enhances the passivation ability at relatively higher potentials. The deep understanding of the passivation characteristics in multicomponent alloy systems could provide a guide for the design of corrosion-resistant amorphous alloy coatings for engineering applications.     

工艺参数对低pH值2.0~2.5柠檬酸水溶液电沉积铼铱基合金薄膜特征影响

研究了在低pH值2.0~2.5的柠檬酸水溶液中恒电流电沉积富Re+Ir的Re-Ir-Ni合金薄膜特征,以及镀液温度、镀液pH、电流密度和镀液化学组成对薄膜表面形貌、化学成分和晶体结构的影响。采用环境扫描电子显微镜、X射线能谱仪和X射线衍射仪分别对合金薄膜的形貌、成分和物相进行了表征。结果表明：在电流密度为60 mA·cm^-2、pH为2.0时,获得致密光亮的Re-Ir合金薄膜。在pH=2.5时,提高镀液温度可获得质量良好的合金薄膜,而pH=2.0时,则相反。在镀液温度60~70 ℃、pH=2.0时,沉积的合金薄膜由非晶相组成;在镀液温度80 ℃时,薄膜由ReO₃相组成。在电流密度为60 mA·cm^-2、pH值从2.0增加到2.5时,合金薄膜的晶形结构由非晶态转变为晶态和非晶态的混合结构。结晶相为hcp-Ir_0.4Re_0.6和hcp-Ni。     

CORRELATION BETWEEN STRUCTURE OF ELECTROCHEMICALLY DEPOSITED (Fe,Co,Ni)-P LAYERS AND PROCESS CONDITIONS

用测定阴极极化曲线、比色分析、X射线、扫描电镜及电子探针分析等方法系统地研究了(Fe,Co,Ni)-P合金电化学沉积条件与镀层结构的关系。结果表明:电化学沉积条件对镀层结构的影响是通过镀层中磷含量变化实现的;镀液中NaH_2PO_2浓度及pH值是两种主要影响因素;找出了电位与结构关系以及各系非晶态结构小片堆垛最高高度。     

Microstructure and magnetic properties of electrodeposited Gd-Co alloy films

Gd-Co alloy films were synthesized by potentiostatic electrolysis on Cu substrates in urea-acetamide-NaBr-KBr melt at 353 K. The elec- troreduction of Co2 and Gd3 was investigated by cyclic voltammetry. The reduction of Co2 is an irreversible process. Gd3 cannot be re- duced alone, but it can be inductively co-deposited with Co2 . Both the Gd content and microstructure of the prepared Gd-Co alloy films can be controlled by the deposited potential. The content of Gd was analyzed using an inductively coupled plasma emission spectrometer (ICPES), and the microstructure was observed by scanning electron micrograph (SEM). The films were crystallized by heat-treatment at 823 K for 30 s in Ar atmosphere, and then were investigated by XRD. The hysteresis loops of the Gd-Co alloy films were measured by a vibrat- ing sample magnetometer (VSM). The experimental results reveal that the deposited Gd-Co alloy films are amorphous, while the annealing causes the samples to change from amorphous to polycrystalline, thus enhancing their magnetocrystalline anisotropy and coercivity. More- over, the magnetic properties of the Gd-Co alloy films depend strongly on the Gd content.     

Influence of current density in anodizing of an Al–W alloy

The influences of current density in development of amorphous, barrier anodic films on a metastable, solid solution, Al–6.5at.%W alloy is examined, with focus on enrichments in the alloy, oxidation processes at the alloy/film interface and migration of species in the film. The films were formed at current densities between 0.01–100 mA cm⁻² in sodium tungstate electrolyte and examined by transmission electron microscopy and Rutherford backscattering spectroscopy. Enrichments of tungsten in the alloy develop at each of the selected current densities, with enrichments in the range 2–4×10¹⁵ W atoms cm⁻². Incorporation of tungsten species into the films at the alloy/film interface proceeds non-uniformly, with cycles of local enrichment of the alloy, oxidation of the enriched tungsten and subsequent depletion of the alloy. The tungsten species migrate more slowly than Al³⁺ ions, leading to layering of the film composition. The cyclic incorporation of tungsten species into the film and the migration of tungsten species within the film are similar for the selected current densities, at the resolution of the experiments.     

Sweep potential deposition of Tm-Ni-Co alloy films in dimethylsulfoxide

The Tm-Ni-Co alloy films have been prepared by the sweep potential deposition technique. The surface appear-ance of Tm-Ni-Co alloy films was silver smooth and adhesive. The surfaces of Tm-Ni-Co alloy films observed by scanningelectron microscope (SEM) were uniform, adhesive and compact. The sizes of metallic grains were about 80-100nm,100-200nm, 50-60nm, and 90-120nm at 1mV·s~(-1), 5mV·s~(-1), 10mV·s~(-1) and 50mV·s~(-1), respectively. The Tm-Ni-Co alloy film wasamorphous as proven by the X-ray diffraction(XRD).     

Microstructure, corrosion resistance and biocompatibility of titanium incorporated amorphous carbon nitride films

Titanium incorporated amorphous carbon nitride films were deposited by direct current magnetron sputtering. The films change from amorphous to nanocomposite structure, the relative fraction of sp³ C-N bonding decreases significantly from 2.17 to 1.64 with the increase of Ti content from 2.7 at.% to 12.3 at.%. For the films with high Ti content, the nanocrystalline TiN embedded in a-CN_x matrix, while principally TiN did not appear to be well formed for the film containing low Ti content. Potentiodynamic polarization, in vitro human osteoblasts and murine fibroblast cell adhesion tests were employed to assess the corrosion performances of Ti6Al4V alloy coated with the films in Tyrode's solution, and the biocompatibility of Ti-incorporated a-CN_x films, respectively. Titanium incorporation increases the corrosion resistance of a-CN_x films, and the higher corrosion potential and lower corrosion current density are observed for the alloy coated with the film containing lower Ti content. The high osteoblast adhesion and activation demonstrate the enhanced biocompatibility of Ti alloy coated with Ti-incorporated a-CN_x films. The improved biocompatibility in biological environment is attributed to structural change after titanium introduction.     

STUDY ON CO-ELECTRODEPOSITION OF Bi-Fe ALLOY FILMS IN ORGANIC BATH

The cyclic voltametry and potentiostatic electrolysis was used to investigate the preparation of Bi-Fe alloy films in LiClO4-DMSO (dimethylsulfoxide) system. The effects of several factors including the potential of deposition, current density and concentration of iron and bismuth in the solution on the Fe content in the alloy deposits were studied. Experimental results indicated that the amorphous alloy films of Bi-Fe containing Fe 4.40wt%-33.67wt% could be prepared by controlling the system composition and deposition conditions. They were gray, uniform, metallic luster and adhered firmly to the copper substrates analyzed by EDS, SEM and XRD. After heat treatment of crystallization at 270℃ for 1h, the crystal phase of Bi-Fe can be found in XRD patterns.     

An XPS study of anodic behavior of amorphous nickel-phosphorus alloys containing chromium,molybdenum or tungsten in 1 m CHl

The surfaces of amorphous Ni-18P, Ni-IOCr-20P, Ni-9Mo-19P and Ni-5W-18P alloys immersed or anodically polarized in 1 M HCl solution were analyzed in connection with their corrosion and anodic behavior. All alloys were more corrosion-resistant than crystalline nickel metal because of formation of phosphate-containing surface films on the Ni-18P, Ni-9Mo-19P and Ni-5W-18P alloys and because of spontaneous passivation due to formation of passive hydrated chromium oxyhydroxide film on the Ni-10Cr-20P alloy. The latter alloy was stable up to the transpassive region of chromium although intrusion of phosphate in the film was responsible for the higher passive current density in comparison to the amorphous Fe-Cr-13P-7C alloy of the same chromium content. The formation of thick porous phosphate films containing nickel, and molybdenum or tungsten by anodic polarization was not effective in passivating the Ni-18P, Ni-9Mo-19P and Ni-5W-18P alloys, and they suffered pitting corrosion by anodic polarization.