Ni-P/Ni-Zn-P三层复合镀层的制备与耐腐蚀性能研究

目的 制备具有不同电位差的多层阳极Ni-P/Ni-Zn-P复合镀层.方法 采用化学镀的方法,在Q235钢基体表面制备内层为低磷Ni-P合金、中层为高磷Ni-P合金、外层为Ni-Zn-P合金镀层的三层复合镀层.通过金相显微镜、扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、电化学工作站等仪器对复合镀层表面形貌、成分结构及腐蚀电位进行分析.结果 相较于低磷Ni-P镀层和高磷Ni-P镀层,Ni-P/Ni-Zn-P三层复合镀层的晶胞大小均匀一致且胞与胞之间致密平滑.内层低磷Ni-P镀层断面厚度约为14.5μm,镍的质量分数约为96.5％,磷的质量分数为3.5％;中层高磷Ni-P镀层断面厚度约为17.6μm,镍的质量分数约为90.2％,磷的质量分数约为9.8％;Ni-P/Ni-Zn-P三层复合镀层断面总厚度约为40μm,镍的质量分数约为80.7％,锌和磷的质量分数分别为7.6％和11.7％.在Tafel极化曲线中,Ni-P/Ni-Zn-P三层复合镀层的腐蚀电流密度最小,为3.815×10-6 A/cm2,具有更好的耐蚀性.在模拟海水环境(5％NaCl溶液)中腐蚀220 h后,内层、中层组织腐蚀成片,出现孔洞且有点蚀,而Ni-P/Ni-Zn-P三层复合镀层几乎没有腐蚀,只有部分区域出现点蚀,组织较为完整,说明三层镀层较单层、双层镀层具有更好的耐腐蚀性.结论 制备具有电位差的多层阳极Ni-P/Ni-Zn-P复合镀层具有更好的性能,且相较于内层单层、中层双层Ni-P合金镀层,其腐蚀速率也明显降低,耐腐蚀性能更好.     

镀液中Fe~(2+)含量对Ni-P化学镀层耐蚀性能的影响

为进一步提高Ni-P合金镀层的耐蚀性,在Ni-P镀液中添加了不同质量分数的硫酸亚铁(Fe SO4),制备了Ni-Fe-P三元合金镀层。通过扫描电镜观察了镀层的表面形貌,采用能谱仪测试了镀层中各元素的质量分数,采用X-射线衍射仪对各镀层的结构进行了测试,通过交流阻抗考察了各个镀层的耐蚀性。结果表明:该工艺制备的Ni-Fe-P镀层属于高磷镀层,当镀液中Fe SO_4含量分别为0.2、0.5和0.8 g/L时,Ni-Fe-P镀层中Fe元素的质量分数呈下降趋势,镀层在Na Cl溶液中发生腐蚀时的电荷转移电阻不断减小,镀层的耐蚀性逐渐下降。     

硫离子对碳钢腐蚀性的影响

利用恒电位极化法研究了45#碳钢在Na2S溶液中的电化学行为，用失重法研究了45＃碳钢在不同温度、不同浓度Na2S溶液中的腐蚀速率，采用场发射扫描电子显微镜观察其表面的腐蚀形貌.结果表明：在极化电位较低时，腐蚀过程为电化学控制，当电位升高到-0.4 V以后，出现了极限传质扩散区；在同一质量分数Na2S溶液中，温度升高加速了腐蚀反应的阳极过程；45＃碳钢在Na2S溶液中腐蚀速率随Na2S质量分数的增加，先降低后升高；Na2S含量较低时，腐蚀主要为点蚀，Na2S含量较高时，为均匀腐蚀.      

脉冲电沉积纳米晶Ni-Co合金镀层腐蚀特性研究

采用X射线衍射(XRD)、扫描电镜(SEM)、能谱分析(EDS)等方法研究了脉冲电沉积法制各纳米晶Ni和纳米晶Ni-Co合金镀层的组织结构、表面形貌和成分.用浸泡法和电化学极化法研究了纳米晶Ni和不同Co含量的纳米晶Ni-C0合金镀层在3.5%NaCl(质量分数,下同)和5%HCl溶液中的腐蚀行为.结果表明:通过脉冲电沉积法制各的Ni和Ni-Co合金镀层具有典型的纳米晶结构; 随着含Co量的增加,镀层的晶粒尺寸减小,硬度增加;所制备的纳米晶Ni-Co合金镀层组织结构均匀致密,其在3.5%NaCl溶液和5%HCl溶液中的耐蚀性均优于纳米晶Ni镀层;纳米晶Ni-Co合金镀层在3.5%NaCl溶液的浸泡腐蚀中腐蚀极少,表现出优异的耐腐蚀性能,而在5%HCl溶液中的腐蚀形态则为均匀腐蚀.     

钨铜合金化学镀镍磷镀层的腐蚀行为

采用浸渍失重试验法和动电位极化曲线研究了钨铜合金基材和钨铜合金表面化学镀Ni-P合金镀层在不同腐蚀介质溶液中的腐蚀行为.浸渍失重试验结果表明:Ni-P合金在质量分数为3.5%的NaCl溶液、人工模拟汗液和体积分数为10%的H2SO4溶液中的耐腐蚀性能好于钨铜合金;动电位极化曲线研究表明:化学镀Ni-P合金浸入3.5wt.%NaCl溶液后不久其表面便开始形成钝化膜,但此钝化膜不完整,随着浸泡时间的延长,钝化膜不断生长,能在较长时间内(29d)对钨铜合金起到保护作用.     

模拟海洋环境中Ni-Co合金镀层对AZ91D镁合金的腐蚀防护研究

目的提高AZ91D镁合金的腐蚀防护性能。方法采用化学镀前处理在AZ91D镁合金表面制备一种保护性的Ni-Co合金镀层。分别采用环境扫描电镜(ESEM)、X射线衍射(XRD)和能量散射谱(EDS)分析合金镀层的表面形貌、微结构特点和化学成分。采用动电位极化(PC)和电化学阻抗谱(EIS),分析测试在模拟海洋环境(中性3.5%Na Cl溶液)中Ni-Co合金镀层对AZ91D镁合金的腐蚀防护性能。结果镁合金表面化学镀Ni-P镀层均匀覆盖,晶粒生长较致密,表面呈菜花状形貌,Ni-P镀层中P质量分数约为5.6%。Ni-Co合金镀层表面均匀且呈金字塔状形貌,形成了面心固溶体(FCC),镀层中Co质量分数约为31%。Ni-P镀层和Ni-Co合金镀层的厚度分别约为11μm和19μm。在模拟海洋(中性3.5%Na Cl溶液)环境中,镁合金裸基体、化学镀前处理Ni-P镀层、Ni-Co合金镀层的腐蚀电位分别为-1485、-372、-284 m V,其腐蚀电流密度分别是3.4×10-5、1.8×10-6、2.9×10~(-7) A/cm2,所拟合的电荷转移电阻分别为4.72×103、1.70×104、2.06×106?/cm2。结论化学镀前处理Ni-P镀层可为镁合金提供较好的腐蚀防护,Ni-Co合金镀层能够为镁合金提供更显著的腐蚀防护。     

热处理温度对网球拍用钛合金表面Ni-P合金镀层性能的影响

用化学镀方法在钛合金Ti-6Al-4V表面制备了Ni-P合金镀层,并在不同温度下对合金镀层进行了热处理;通过扫描电镜(SEM)、X射线衍射仪(XRD)、硬度测试及摩擦磨损试验研究了热处理温度对Ni-P合金镀层相组成和显微硬度及耐磨性能的影响。结果表明:在400℃热处理2h后,Ni-P合金镀层的结构致密均匀,其显微硬度最高,达到910HV,耐磨性能也最好。     

化学镀Ni-P合金镀层在海水中的耐蚀性

在Cu-Ni合金表面化学镀Ni-P合金,研究了镀层在3.5%NaCl溶液中的电化学性能,通过失重法测试了Ni-P合金镀层、Cu-Ni合金在静态和动态海水中的腐蚀速率,利用表面分析技术研究了Ni-P合金镀层的组织结构与成份XRD分析结果表明Ni-P镀层是典型的非晶态合金,随着镀层P含量的增加,衍射峰越来越宽化,其非晶化的程度增高.动电位极化试验表明Ni-P镀层的耐蚀性主要受镀层中的P含量的影响,随P含量的增加,镀层的自腐蚀电位正移,腐蚀电流减小;失重试验表明Ni-P合金镀层在静态海水和流动海水中的腐蚀速率大大低于Cu-N合金     

Ni-Zn-P合金镀层在人工模拟海水中腐蚀行为的研究

目的 提高金属材料在海洋环境中的耐腐蚀性和使用寿命.方法 采用碱式化学镀方法 在Q235碳钢表面施镀Ni-P镀层和Ni-Zn-P合金镀层,镀液配方NiSO4·6H2 O 20~25 g/L,C6 H5 O7 Na3·2H2 O 50~70 g/L,NH4Cl 25~30 g/L,NaH2PO2·H2O 15~25 g/L.制备Ni-Zn-P合金镀层时,在以上配方中加入0.4~0.8 g/L ZnSO4·7H2 O.采用金相显微镜和扫描电子显微镜(SEM)观察镀层在人工模拟海水中腐蚀前后的组织形貌,用能谱分析仪(EDS)分析镀层腐蚀前后表面成分.结果 Ni-P镀层和Ni-Zn-P合金镀层中的P质量分数分别为11.26%和9.97%.从P含量和镀层组织形貌,可以确定得到的两种镀层是连续致密的非晶镀层.Ni-Zn-P合金镀层比Ni-P镀层的胞状组织更加均匀平滑,胞与胞的边界结合更加连续致密.在人工模拟海水中腐蚀144 h后,Ni-P镀层出现明显的点蚀坑,Ni-Zn-P合金镀层仍然连续完整.Ni-Zn-P合金镀层腐蚀后,Zn含量明显下降,并出现少量的Fe和O,表明合金镀层腐蚀过程是Zn优先被腐蚀,然后镀层逐渐被腐蚀破坏,最后基体发生腐蚀.Ni-Zn-P合金镀层的腐蚀速率明显低于Ni-P镀层的.结论 Ni-Zn-P合金镀层的胞状组织比Ni-P镀层的更加均匀平滑,胞与胞的边界结合更加连续致密,Ni-Zn-P合金镀层腐蚀速率明显低于Ni-P镀层.     

Zr-8.8Al合金化学镀前的磷化预处理工艺

预处理工艺的选择直接影响化学镀Ni-P镀层质量的高低。采用磷化法对Zr-8.8Al合金进行了化学镀前的预处理,研究了Zr-8.8Al合金在不同磷化工艺下获得的磷化膜以及化学镀Ni-P镀层的显微结构、显微硬度、抗蚀性等。结果表明,45℃/2 min预处理获得的磷化膜均匀致密;在此工艺下进行化学镀获得的Ni-P镀层为非晶、胞状结构,厚度达25μm。与裸材相比,Ni-P镀层显微硬度提高了60%,在质量分数为3.5%的Na Cl溶液中自腐蚀电位发生正移,极化腐蚀后镀层胞状较完整,对Zr-8.8Al合金起到了较好的保护作用。     

The structure and properties of electroless Ni–Mo–Cr–P coatings on copper alloy

In the present study, the quaternary Ni–Mo–Cr–P alloy coatings were deposited on copper alloy by an electroless deposition process. Crystallization behavior and the effect of heat‐treatment on hardness and corrosion resistance of Ni–Mo–Cr–P deposits were detailedly investigated. X‐ray diffraction (XRD) analysis shows that as‐deposited Ni–Mo–Cr–P coatings are Ni–Mo–Cr–P solid solution and mixed crystal structure; the trend of microcrystallinity increases with the introduction of additional types of metal element; Ni–Mo–Cr–P alloy coatings start to occur in the crystallization with the heat‐treatment temperature increasing. With an increase in the annealing temperature, the hardness improves and reaches the maximum value at 500 °C. Further, it is found that Ni–Mo–Cr–P coatings have superior corrosion resistance than Ni–P and Ni–Mo–P deposits after the analysis of electrochemical measurements. Moreover, corrosion resistance increases before annealed at 400 °C, but heat‐treatment at higher temperatures has a negative effect on the corrosion resistance of Ni–Mo–Cr–P alloy coatings.     

The effect of TiO2 nanoparticle codeposition on microstructure and corrosion resistance of electroless Ni?P coating

Ni? P? TiO₂ nanocomposite coatings with various contents of TiO₂ nanoparticles were synthesized by adding TiO₂ nanoparticles to Ni? P electroless plating solution. The effects of pH and anionic surfactant sodium dodecyl sulfate (SDS) on the chemical composition of Ni, P, and TiO₂ in the coatings were investigated. Scanning electron microscope (SEM), energy dispersive spectrometer (EDX), and X‐ray diffractometer (XRD) were used to characterize the morphology, composition, and crystal structure of deposited coatings, respectively. The hardness of nanocomposite coatings was improved greatly compared to Ni? P coating especially after heat treatment. After heat treatment at 400 °C for 1 h, an increase in microhardness was observed for heat‐treated Ni? P coatings. The hardness was increased from 805 to 1050 Hv for Ni? P? TiO₂ coating deposited at 9 g/LTiO₂ concentration in the bath. The corrosion resistance of Ni? P? TiO₂ coating was significantly increased compared to Ni? P coatings by incorporation of TiO₂ nanoparticle.     

Electrochemical behavior of Ni?P?SiC composite coatings: Effect of heat treatment and SiC particle incorporation

This paper describes the effects of heat treatment and of SiC particle incorporation on the electrochemical behavior and physical structure of Ni? P (17 at% P) composite coatings. The deposits were obtained by electrodeposition with various contents of SiC particles in the plating bath and heat treated at 420 °C. The physical structure was investigated by inductively coupled plasma atomic emission spectrometry (ICP‐AES), X‐ray diffraction (XRD), and scanning electron microscopy (SEM – image analysis). The electrochemical behavior of the resultant composite coatings was determined by chronopotentiometry, electrochemical impedance spectroscopy, and potentiodynamic measurements in 0.6 M NaCl solution at pH 6. Heat treatment showed a positive effect on the electrochemical behavior of Ni? P coatings, shifting the open circuit potential toward less active potentials. The incorporation of SiC particles inhibited pit nucleation on the Ni? P composite coating, with or without post‐heat treatment. However, heat treatment in the Ni? P? SiC seemed to induce cracks in the metallic matrix, initiating at the SiC particles, possibly caused by the contraction in the metallic matrix. The cracked structure promoted localized corrosion, while coatings without heat treatment resulted in a general and uniform corrosion.     

Microstructure and properties of open-cell Ni–Sn–P alloy foams prepared by electroless plating

In this study, open-cell Ni–Sn–P alloy foams were prepared by electroless plating. The influence of tin content on the surface morphology and properties of Ni–Sn–P alloy foams were investigated. The surface structure of Ni–Sn–P alloy foams became more uniform and compact with the increase of Sn content. The X-ray diffraction result showed that Ni–Sn–P alloy foams gradually transformed from an amorphous structure into crystallization with the increase of heat-treatment temperature. The introduction of Sn significantly enhanced the corrosion resistance of Ni–P coatings in 3.5 wt% NaCl solution, the corrosion current density decreased from 5.022 to 0.805 μA/cm² and the corrosion potential shifted positively from −0.423 to −0.294 V after adding 5.96 wt% Sn to Ni–P coatings. However, the corrosion resistance of Ni–Sn–P foams was deteriorated after heat treatment. Adding Sn to the Ni–P system slightly weakened the compressive strength of Ni–P binary foams. Nevertheless, significant improvement in the antioxidant performance of Ni–Sn–P alloy foams was indicated by the reduction of the mass change rate in that the mass change rate of Ni–P foams obviously reduced from 5.15% to 0.25% after adding 5.96 wt% Sn.     

镀液组分对高Sn含量Ni-Sn-P镀层组织和镀速的影响

为获得耐蚀性较好的NiSnP镀层及其最佳镀液配方,利用正交试验方法设计了9种不同的镀液组分,利用化学镀技术在L245低碳钢上镀制了高Sn含量的NiSnP三元镀层。采用扫描电子显微镜和X射线衍射仪对镀层的成分、结构以及镀速进行分析,并采用盐雾腐蚀实验评价镀层的耐蚀效果。结果表明： 高Sn含量的NiSnP镀层组织以非晶态结构为主,表面形态为典型的胞状结构。当乳酸和硫酸镍为较低浓度,氯化锡和柠檬酸钠为高浓度时,NiSnP镀层的形核率较高,镀层表面形貌较好。镀液中柠檬酸钠和硫酸镍对镀层的沉积过程有利,浓度越大,镀层沉积越快,而乳酸对镀层的沉积不利。35 g/L硫酸镍、35 g/L氯化锡、25 g/L柠檬酸钠和40 mL/L乳酸为最佳镀液组分,在该条件下获得的NiSnP镀层耐蚀效果最好。     

几种不同材料在含硫介质中的腐蚀性

用失重法和恒电位极化法研究了45#碳钢、1Cr18Ni9Ti、304不锈钢和Ni-P合金镀层在含S介质中的腐蚀性.结果表明,低温条件下,S2-浓度变化对4种材料阴极极化和阳极极化影响较小,1Cr18Ni9Ti和304不锈钢的极化曲线相似,为典型的阴、阳极控制的电化学腐蚀过程,自腐蚀电位和自腐蚀电流相近;Ni-P合金镀层出现了钝化区;45#碳钢出现了阳极控制的扩散过程.温度升高,腐蚀速率增大,1Cr18Ni9Ti和304不锈钢的极化率变大,Ni-P合金镀层的钝化性能减弱, 1Cr18Ni9Ti、304不锈钢和Ni-P合金镀层均是含S介质中的耐蚀材料.     

Preparation and characterization of inorganic and organic coatings on AZ91D magnesium alloy with electroless plating pretreatment

In this paper, a protective coating scheme was applied for the corrosion protection of AZ91D magnesium alloy. Electroless Ni coating (EN coating) as bottom layer, electrodeposited Ni coating (ENN coating), and silane‐based coating (ENS coating) as top layer, respectively, were successfully prepared on AZ91D magnesium alloy by combination techniques. Scanning electron microscopy and X‐ray diffraction were employed to investigate the surface and phase structure of coatings, respectively. The electrochemical corrosion behaviors of coatings in neutral 3.5 wt% NaCl solution were evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The corrosion testing showed that the three kinds of coatings all could provide corrosion protection for AZ91D magnesium alloy to a certain extent, and the corrosion resistance of ENN and ENS was superior to EN. In order to further study the corrosion protection properties of ENN and ENS, a comparative investigation on the evolution of EIS of ENN and ENS was carried out by dint of immersion test in neutral 3.5 wt% NaCl solution. The results indicated that, compared with ENN, the ENS could provide longer corrosion protection for AZ91D magnesium alloy. It is significant to determine the barrier effect of each coating, which could provide reference for industry applications.     

氯离子浓度对Ni-P合金涂层失效过程影响的SECM实验和COMSOL模拟研究

目的发展具有空间分辨的腐蚀电化学研究方法。方法用电沉积方法在铜基体上制备Ni和Ni-P涂层,应用扫描电镜和XRD检测涂层表面形貌和晶体结构,采用扫描电化学显微镜(SECM)研究Ni和Ni-P涂层在不同浓度Na Cl溶液中的失效行为,并结合COMSOL多物理场软件建立二维和三维模型,模拟量化活性点大小和反馈机制。结果低浓度Cl-对于纯Ni涂层具有活化作用,增加Cl-浓度会促进腐蚀发生。Ni-P合金涂层在低浓度Na Cl溶液中,短时间内保持良好的稳定性,浸泡6 h后,低P合金涂层出现典型的活性点和腐蚀产物,而高P合金涂层在浸泡24 h后出现腐蚀产物和活性区域。0.1 mol/L的Na Cl溶液促进低P合金涂层局部腐蚀的发生,而涂层在0.3 mol/L Na Cl溶液中则以发生均匀腐蚀为主。逼近曲线及其模拟结果表明,腐蚀产物对于Fc Me OH的电化学过程完全失活,而新鲜Cu表面对Fc Me OH氧化还原过程受扩散控制。三维模拟结果显示,低P合金涂层失效过程中活性点大小接近10μm。结论 Ni和Ni-P合金涂层的失效过程中活性点的形成、腐蚀产物的生成和累积过程与SECM面扫描图谱中正负反馈效应相关,Cl-促进腐蚀发生,其浓度影响腐蚀类型。COMSOL多物理场模拟明确反馈效应与探针和基底的距离有关,Ni-P涂层失效活性点大小在微米级。     

TL电刷镀Ni-Cu-P非晶态合金工艺研究

采用电刷镀技术,利用扫描电镜、能谱分析仪、X光衍射仪等测试手段,对三元Ni-Cr-P合金刷镀溶液的配方组成、施镀工艺、镀层组织结构及成份进行了分析研究,确定了三元Ni-Cu-P镀液的组成及刷镀工艺。研究结果表明：该镀层具有良好的综合性能,并可镀厚,且镀层表观 光泽平整。     

化学镀Ni—Cr—P合金镀层在NaCli溶液中的耐蚀性

用电化学方法研究了化学镀Ｎｉ－Ｃｒ－Ｐ合金镀层在３．５％ＮａＣｌ溶液中的耐蚀性,结果表明Ｎｉ－Ｃｒ－Ｐ镀层与Ｎｉ－Ｐ镀层的阳极极化曲线形状相似,自腐蚀电位正移１５０ｍＶ以上,自腐蚀电流降低近３倍,在钝化区的阳极是约１个数量级,镀层的耐蚀性提高。