摩擦电喷镀镍基纳米氧化铝镀层组织及性能研究

制备出摩擦电喷镀n-Al2O3/Ni镀层与电刷镀n-Al2O3/Ni镀层.用SEM、XRD和HMT-3显微硬度计观测出摩擦和喷射使得镀层更平整、细腻,且复合含量、硬度与刷镀层相比有明显提高;2种镀层在5%H2SO4溶液和5%H2SO4 3.5%NaCl溶液中腐蚀,通过公式v=△w/st=A·i∞rr/(nF)推出摩擦电喷镀n-Al2O3/Ni镀层腐蚀速率最小.     

Ni-SiC复合梯度镀层的耐腐蚀性能

Ni-SiC复合梯度镀层比普通复合镀层性能要优,应用要广,但过去对其耐蚀性研究不多.通过对电流密度、搅拌强度和镀液中Sic浓度等电镀工艺条件的优化,制备了新型Ni-SiC复合梯度镀层.采用扫描电镜对其表面和断面形貌进行了观察,并借助电化学手段研究了Ni-SiC复合镀层在3.5%Nacl腐蚀液和3.5%NaCl+0.3%H2O2腐蚀液中的耐蚀性能.结果表明:在复合镀层中,SiC微粒沿镀层生长的方向呈梯度分布,在镀层表面呈均匀弥散分布;在3.5%.NaCl腐蚀液中纯镍镀层的耐腐蚀能力与复合镀层相当;在3.5%NaCl+0.3%H2O2腐蚀液中,由于SiC微粒包裹在Ni-SiC复合镀层内,彻底改变了镀层的表面形貌和组织结构,细化了镀层晶粒,所以改善了Ni-SiC复合镀层的耐蚀性能.     

Ni/SiC复合镀层腐蚀行为研究

研究了Ni/SiC复合镀层在3.5%NaCl溶液中的腐蚀行为.测定了Ni/SiC镀层在NaCl溶液中的失重曲线,利用solartron恒电位仪测定其极化曲线,借助扫描电镜对镀层表面形貌进行了观察.结果表明,随着腐蚀时间的延长,腐蚀失重逐渐增加,但腐蚀速率逐渐降低;Ni/SiC复合镀层与纯Ni镀层耐盐水腐蚀能力基本相当;Ni/SiC复合镀层在3.5%NaCl溶液中的开路电位要高于纯Ni镀层的开路电位;在3.5%NaCl H2O2溶液中,两种镀层的开路电位均明显正移,且Ni/SiC复合镀层自腐蚀电流降低,说明复合镀层耐盐水腐蚀能力有所提高.镀Ni层中引入SiC颗粒能使其组织细化,并促进复合镀层在3.5%NaCl溶液中发生钝化,可能是Ni/SiC镀层在盐水中耐蚀性能提高的主要原因.     

脉冲电沉积Ni-P/BN(h)复合镀层的组织结构与性能

目前,鲜见对Ni-P/Bn(h)复合电沉积层的制备及其性能的研究报道。在Q235钢表面脉冲电沉积了Ni-P/BN(h)复合镀层,并于400℃热处理80 min,对热处理镀层的组织结构、显微硬度、耐蚀性能和摩擦学性能进行了分析测试。结果表明:镀态复合镀层为非晶态结构,400℃热处理后发生晶化,显微硬度显著提高,达到907.5 HV2 N;在3.5%NaCl和10%H2SO4腐蚀介质中,镀层几乎未发生全面腐蚀;镀层在干摩擦条件下表现出良好的减摩耐磨性能,低载时为轻微磨粒磨损,随载荷增大表现为磨粒磨损和黏着磨损的混合磨损机制。     

Ni-Cu-P化学镀层的腐蚀行为

为了进一步提高Ni-P镀层的耐蚀性能,在Ni-P化学镀液中加入硫酸铜制备了Ni-Cu-P三元合金化学镀层,测试了镀层的沉积速度,采用扫描电镜(SEM)观察了镀层的表面形貌,测试了镀层在5.0%H2SO4,5.0%NaOH及3.5%NaCl溶液中的动电位极化曲线,并与Ni-P化学镀层进行了比较。结果表明:Ni-Cu-P镀层表面的胞状物比Ni-P镀层的更加细小,镀层致密性更好;Ni-Cu-P镀层在3种介质中均表现出更好的耐均匀腐蚀性和抗点蚀性能,主要是因为Ni-Cu-P镀层的非晶态结构减少了镀层缺陷数量,从而减少了腐蚀发生的敏感位置和腐蚀微电池的数量,同时更加细小的晶粒也使Ni-Cu-P镀层比Ni-P镀层更容易钝化和维持钝态,另外Ni-Cu-P镀层更为致密也减少了腐蚀介质渗入基体的通道。     

镍-钴／镍／镍-钴镀层的制备及电化学性能

采用直流和脉冲方法电沉积了镍-钴／镍／镍-钴多层镀层。通过SEM对镍-钴／钞镍-钴镀层的微观结构进行了表征,采用Tafel曲线外推法、交流阻抗法、阳极极化曲线法等方法对镍-钴／镍／镍-钴镀层在0．1mol／LH2SO4和1％NaCl混合溶液及10％NaOH溶液中的耐腐蚀性能进行了表征。结果显示：镍-钴／镍／镍-钴镀层的表面致密均一;在0．1mol／LH2SO4＋1％NaCl溶液中的腐蚀电位最正,传质电阻最大达到i642Q·cm2;在10％NaOH中钝化区为542mV,具有较好的钝化效果。     

热处理对Ni-P合金镀层组织结构、显微硬度与耐蚀性能的影响

目前,有关热处理对Ni-P合金镀层组织结构与性能的影响研究不够深入。采用脉冲电沉积方法在Q235钢表面制备Ni-P合金镀层,并在200～500℃下进行热处理。利用X射线衍射仪分析镀层的相结构,用电化学极化曲线和扫描电子显微镜(SEM)对镀层在3.5%NaCl,10%HCl和10%H2SO4溶液中的腐蚀行为进行了研究。结果表明,提高热处理温度,Ni3P相的析出速度增大,Ni-P合金镀层的晶化时间减少,达到最高硬度所需的热处理时间相应缩短,镀层经300℃和400℃热处理后的最高硬度分别达到862.8 HV2N和887.4HV2 N;Ni-P合金镀层热处理晶化后,其耐蚀性能显著降低,在3种腐蚀介质中均发生点蚀。     

化学镀镍磷层孔隙率的电化学评价

钢铁基体上的化学镀镍磷层属于阴极保护镀层,其孔隙率测定非常重要.为此,对化学镀镍磷层孔隙率电化学测定方法进行了探索.通过研究钢铁和化学镀镍磷层在不同介质中电化学行为的区别,选择了5%H2SO4作为测试介质,并研究了该介质中不同孔隙率镀镍磷层的电化学行为.结果表明:随镀层孔隙率的减少,镀层的自腐蚀电位逐渐从铁的自腐蚀电位向纯镍磷镀层的自腐蚀电位变化.而应用常规的孔隙率检测方法只能检测较大的孔隙.电化学方法与贴滤纸法孔隙率测试结果是一致的,说明该方法可行.     

Ni-P-TiO2纳米复合镀层的制备及性能研究

用化学沉积方法制备了Ni-P-TiO2纳米复合镀层,通过XRD、SEM、TEM和EDS对纳米复合镀层进行了表征,分析了在3.5%NaCl溶液中TiO2纳米颗粒浓度对纳米复合镀层的耐蚀性能影响,研究了热处理温度对复合镀层显微硬度的影响.结果表明:所得复合镀层中纳米粒子的复合量可达到11.33%;在3.5%NaCl溶液中,当TiO2浓度为8g/L时复合镀层腐蚀电位最高,耐蚀性能最好;在镀态或热处理后,复合镀层的硬度都明显高于Ni-P合金镀层,且经过400℃热处理后,复合镀层的硬度高达Hv1160.     

低温退火对电沉积纳米晶Ni镀层耐蚀性的影响

通过脉冲电沉积方法制备纳米晶Ni镀层。采用浸泡法和电化学方法研究了不同温度低温退火纳米晶Ni镀层在3.5wt.%NaCl和5wt.%HCl溶液中的腐蚀行为。结果表明:150℃以下退火,晶粒未出现明显长大。在3.5wt.%NaCl溶液中,镀层耐蚀性随退火温度的升高而提高;200℃退火后镀层的耐蚀性最好,镀层表面均有钝化现象。在5wt.%HCl溶液中,退火后镀层的耐蚀性有所提高,但退火温度的影响不大,镀层腐蚀过程中未观察到钝化现象。     

液体润滑油微胶囊复合电沉积镍的研究

讨论了用水相分离法制备含有液体微胶囊的技术，并且将以润滑油为囊心的液体微胶囊加入到氨基磺酸镍镀液中进行复合共沉积，得到了含有液体润滑油微胶囊的复合镀镍层。通过对这种镀层的表面、断面形貌和成分分析，证实和确认了这种含有液体微胶囊的复合镀镍层。通过阳极极化曲线、3．5％NaCl溶液浸渍腐蚀试验、耐磨试验等结果表明含有润滑油为囊芯的微胶囊的复合镀镍层具有优良的耐腐蚀性和耐磨性。     

Ni-P/纳米SiC复合镀层的电化学行为及耐蚀性能

为了深入研究纳米SiC对Ni-P电镀层在NaCl溶液中的电化学行为的影响,电沉积制备了Ni-P/纳米SiC复合镀层。采用扫描电子显微镜(SEM)观察了镀层的微观形貌,利用动电位极化曲线和交流阻抗技术研究了Ni-P/纳米SiC复合镀层在3.5%NaCl溶液中的电化学行为。结果表明:经过24 h浸泡,非晶Ni-P镀层和Ni-P/SiC2复合镀层在3.5%NaCl溶液中具有较高的电荷转移电阻,表现较好的耐蚀性;Ni-P/SiC20复合镀层在NaCl溶液中随着浸泡时间的延长,Nyquist谱半圆弧减小,因而镀层耐蚀性较差。     

Preparation and characterization of Ni-Cu-P/CNTs quaternary electroless composite coating

Ni-Cu-P/carbon nanotubes (CNTs) quaternary composite coatings were successfully obtained on low carbon steel matrix by electroless plating. The effects of CNTs concentration in the bath on the microstructure of the composite coatings, CNTs content in the composite coatings and the hardness of composite coatings before and after heat treatment at 400 °C have been studied. In addition, the corrosion resistance of Ni-Cu-P/CNTs composite coatings was evaluated by anodic polarization curves in 3.5 wt.% NaCl solution at room temperature. It was noted that the CNTs concentration remarkably influenced the surface morphology of the coatings. With increasing CNTs concentration, both the CNTs content in the composite coatings and the hardness of composite coatings increased at first and then decreased. And the composite coatings after heat treatment provided higher hardness than the as-deposited coatings. The corrosion resistance of Ni-Cu-P/CNTs composite coatings is excellent compared with that of Ni-Cu-P coatings.     

电化学方法评价纳米炭黑复合涂料的防腐性能

通过表面接枝改性获得了亲油性的纳米炭黑粒子,扫描探针显微镜(SPM)和透射电镜(TEM)测试结果表明:炭黑粒子的尺寸为24～300nm.在超声场下,将纳米炭黑均匀分散到醇酸调和漆中,制备了纳米炭黑复合涂料,抗Cl-离子腐蚀能力提高.采用电化学方法(阳极极化和交流阻抗)对纳米复合涂料的耐蚀性进行了评价,测试结果与浸泡腐蚀实验结果完全一致.     

电刷镀Ni-CNTs/PTFE纳米复合镀层的摩擦磨损与耐腐蚀性能

再制造工程中很多表面镀层要求具有优异的摩擦磨损与耐腐蚀性能,利用纳米电刷镀技术在45钢基材上制备NiCNTs、Ni-CNTs/PTFE、Ni-WC/PTFE-CNTs复合镀层。采用XRD和SEM观察电刷镀复合镀层表面相结构和微观形貌,采用球盘式摩擦磨损试验机测试其在干摩擦条件下的摩擦磨损性能,采用动电位极化曲线研究其在3.5%NaCl溶液中的电化学腐蚀行为。结果表明:Ni-WC/PTFE-CNTs复合镀层耐磨性能最优,其次为Ni-CNTs/PTFE、Ni-CNTs复合镀层,均强于纯镍镀层;当CNTs质量浓度分别为1.5g/L和1.0g/L时,Ni-CNTs复合镀层分别表现出最优的摩擦磨损性能和最佳的耐腐蚀性能,Ni-WC/PTFE-CNTs、Ni-CNTs/PTFE复合镀层次之。纯镍镀层和Ni-CNTs复合镀层的磨损机制是粘着磨损,Ni-CNTs/PTFE复合镀层的磨损机制主要是粘着磨损,其次为磨粒磨损,Ni-WC/PTFE-CNTs复合镀层的磨损机制主要是磨粒磨损和接触疲劳磨损。     

A study of corrosion performance of electroless Ni–P and Ni–W–P coatings on AZ91D magnesium alloy

The autocatalytic nature of the electroless nickel‐based alloy coating process will inevitably produce H₂ bubbles which may be left in electroless nickel‐based alloy coating. If the H₂ cannot be removed and left in the coating, it can lead to its poor corrosion resistance due to hydrogen cracks. So, the post treatment is an essential step for electroless deposition process. In this paper, electroless Ni–P and Ni–W–P coatings with chromium‐free pretreatment and dehydrogenation post treatment have been successfully prepared on AZ91D magnesium alloy, and the corrosion behaviors of the two kind coating samples in NaCl solution, HCl solution, and H₂SO₄ solution have been investigated. Both the polarization test and immersion tests show that the electroless Ni–W–P coating has better corrosion resistance than that of electroless Ni–P coating.     

Corrosion protection of ENIG surface finishing using electrochemical methods

Four types of thin film coating were carried out on copper for electronic materials by the electroless plating method at a pH range from 3 to 9. The coating performance was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization testing in a 3.5 wt.% NaCl solution. In addition, atomic force microscopy and X-ray diffraction were also used to analyze the coating surfaces. The electrochemical behavior of the coatings was improved using the electroless nickel plating solution of pH 5. The electroless nickel/immersion gold on the copper substrate exhibited high protective efficiency, charge transfer resistance and very low porosity, indicating an increase in corrosion resistance. Atomic force microscopy and X-ray diffraction analyses confirmed the surface uniformity and the formation of the crystalline-refined NiP {1 2 2} phase at pH 5.     

The fabrication and corrosion behavior of electroless Ni-P-carbon nanotube composite coatings

Ni-P-carbon nanotube (CNT) composite coatings were fabricated successfully from a suspension of CNT in an electroless bath. The microhardness and corrosion behavior of the composite coatings were investigated. The electrochemical properties of the composite coatings were studied using electrochemical workstation system. The corrosion behavior of the amorphous Ni-P-CNT composite coatings was evaluated by polarization curves and electrochemical impedance spectroscopy in 0.1 mol/l NaCl solution at room temperature. It was noted that the amorphous Ni-P-CNT composite coatings provided higher corrosion resistance than the amorphous Ni-P coating. The mechanism of improvement of the electrochemical properties of the electroless composite coatings was also discussed.     

含碳纳米管有机无机复合涂层的制备与防护性能

为了改善铝合金材料的耐腐蚀性能, 研究了以正硅酸乙酯（TEOS）为主要原料, 加入一定量的KH-550, 并引入部分羟基化的多壁碳纳米管（MWCNTs-OH）进行复合, 以冰乙酸为催化剂, 采用溶胶---凝胶法在铝合金基体表面形成复合涂层。腐蚀电化学测试和扫描电镜分析结果表明, MWCNTs-OH的引入能够明显提高涂层的防护性能, 并有效防止涂层开裂。考察了MWCNTs-OH含量和热处理温度对涂层性能的影响。结果表明: MWCNTs-OH质量分数为0.04%、 热处理温度为130℃时制备的涂层性能最佳, 相应的试样在3.5wt%NaCl溶液中的腐蚀电流密度约为3.056×10-8A/cm2, 而同等实验条件下铝合金基体腐蚀电流密度为7.216×10-5A/cm2, 涂层的存在使腐蚀速率降低了3个数量级, 涂层对铝合金基体具有显著的防护效果。      

SiO2粒径对Ni-Co-SiO2复合镀层性能的影响

长期暴露在海洋环境中的钢质紧固件的腐蚀问题严重影响了海洋工程装备和设施的服役安全性。电镀合金镀层是紧固件常用的防护方法,其中,镍钴合金镀层具有较好的耐蚀性。通过向Ni-Co镀液中添加不同粒径的SiO₂颗粒,利用电沉积技术在45钢基体上制备Ni-Co-SiO₂复合镀层。之后,分析了SiO₂粒径对复合镀层表面形貌和显微结构的影响,评价了复合镀层在3.5%（w）的NaCl溶液中的耐蚀性能,并对复合镀层的显微硬度和摩擦系数进行了测试。结果表明,随着镀液中SiO₂粒径的增大,复合镀层表面的SiO₂分布均匀性先增大后减小,当SiO₂粒径为70 nm时,镀层表面形成较完整的SiO₂膜层。动电位极化和电化学阻抗谱测试表明,掺杂70 nm的SiO₂的复合镀层具有最好的耐蚀性。随着镀液中SiO₂粒径增大,复合镀层的硬度逐渐降低,但其对摩擦系数的影响较小。