Corrosion Behavior of Electrodepositing Ni/Al_2O_3 Composite Coatings under the Presence of NaCl Deposit

The morphology and corrosion behavior of Ni/Al2O3 composite coatings prepared using double-pulsed electrodepositing technique after oxidized under 800 ℃ NaCl deposit in air environment were analyzed by scanning electrical microscope (SEM), X-ray diffraction(XRD) and energy dispersive spectrum(EDS). The results showed that the corrosion of all composite coatings was accelerated under NaCl deposits, and the corrosion products were rather porous with poor adherence to the matrix. Al2O3 particles in the coatings can refine the grain size and improve the high temperature corrosion resistance of the coatings. Within the test scope, the more Al2O3 particles in the coatings, the lower corrosion rates could be obtained, and the corrosion mechanism was also discussed.

Preparation and tribological performance of electrodeposited Ni-TiB_2-Dy_2O_3 composite coatings

TiB2 and Dy2O3 were used as codeposited particles in the preparation of Ni-TiB2-Dy2O3 composite coatings to improve its performance. Ni-TiB2-Dy2O3 composite coatings were prepared by electrodeposition method with a nickel cetyltrimethylammonium bromide and hexadecylpyridinium bromide solution containing TiB2 and Dy2O3 particles. The content of codeposited TiB2 and Dy2O3 in the composite coatings was controlled by adding TiB2 and Dy2O3 particles of different concentrations into the solution, respectively. The effects of TiB2 and Dy2O3 content on microhardness, wear mass loss and friction coefficients of composite coatings were investigated. The composite coatings were characterized by X-ray diffraction （XRD）, inductively coupled plasma-atomic emission spectrometer （ICP-AES） and scanning electron microscopy （SEM） techniques. Ni-TiBE-Dy2O3 composite coatings showed higher microhardness, lower wear mass loss and friction coefficient compared with those of the pure Ni coating and Ni-TiB2 composite coatings. The wear mass loss of Ni-TiB2-Dy2O3 composite coatings was 9 and 1.57 times lower than that of the pure Ni coating and Ni-TiB2 composite coatings, respectively. The friction coefficient of pure Ni coating, Ni-TiB2 and Ni-TiB2-Dy2O3 composite coatings were 0.723, 0.815 and 0.619, respectively. Ni-TiBE-Dy2O3 composite coatings displayed the least friction coefficient among the three coatings. Dy2O3 particles in composite coatings might serve as a solid lubricant between contact surfaces to decrease the friction coefficient and abate the wear of the composite coatings. The loading-bearing capacity and the wear-reducing effect of the Dy2O3 particles were closely related to the content of Dy2O3 particles in the composite coatings.

Laser Cladding Al-Si/Al_2O_3-TiO_2 Composite Coatings on AZ31B Magnesium Alloy

To improve the wear resistance and corrosion resistance of magnesium alloys, a 5 kW continuous wave CO2 laser was used to investigate the laser surface cladding on AZ31 B magnesium alloys with Al-Si/Al2O3-TiO2 composite powders. A detailed microstructure, chemical composition, and phase analysis of the composite coatings were studied by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and X-ray diffraction （XRD）. The laser cladding shows good metallurgical bonding with the substrate. The composite coatings are composed of Mgl7Al12, Al3Mg2, Mg2Si, Al2O3, and TiO2 phases. Compared to the average microhardness （50HV0.05） of the AZ3 1 B substrate, that of the composite coatings （230HV0.05） is improved significantly. The wear resistances of the surface layers were evaluated in detail. The results demonstrate that the wear resistances of the laser surface-modified samples are considerably improved compared to the substrate. It also show that the composite coatings exhibit better corrosion resistance than that of the substrate in 3.5wt% NaCI solution.

SLM铝合金表面喷射电沉积Ni-MoS_(2)自润滑复合涂层

采用喷射电沉积在SLM铝合金表面制备Ni-MoS_(2)自润滑复合涂层。用摩擦磨损试验机评价镀液中MoS_(2)浓度对Ni-MoS_(2)自润滑复合涂层摩擦磨损性能的影响。结果表明:共沉积MoS_(2)微粒能有效降低Ni-MoS_(2)自润滑复合涂层的摩擦系数和磨损率。与纯Ni涂层相比,Ni-MoS_(2)自润滑复合涂层与316L钢球对磨的摩擦系数和磨损率显著降低,摩擦系数从0.51降至0.12,磨损率从0.41 mg/m降至0.11 mg/m,为SLM铝合金表面改善摩擦学性能提供了参考。

Ni-SiO_2复合镀层腐蚀摩擦学性能研究

利用瓦特型复合镀液制备Ni SiO2 复合镀层 ,探讨了电沉积过程和获得的镀层的性质 ;尤其是电流密度对获得的Ni SiO2 复合镀层的性能和结构的影响。结果表明 ,Ni SiO2 复合镀层的硬度可达到HVM4 1 0 .2。在 3%NaCl溶液中 ,Ni SiO2 复合镀层磨损量比纯镍层降低 5 0 % ,比A3钢的磨损量降低 86 %。电化学测试结果表明 ,Ni SiO2复合镀层在 3%NaCl溶液中的腐蚀电流比纯镍镀层降低 4 3% ,表现出较好的耐腐蚀性能。SEM分析显示Ni SiO2复合镀层表面是由SiO2 在Ni基体上紧密堆积而成 ,Ni与Si的组分比是 3.4∶1 .2。X射线分析显示Ni SiO2 复合镀层中Ni为面心立方结构 ,其晶粒尺寸为 1 9.1nm。

超声波辅助铁基体电沉积Zn-Ni-P/纳米ZrO_(2)复合镀层及性能研究

通过电沉积并辅助超声波振荡在铁基体上制备出Zn-Ni-P/纳米ZrO_(2)复合镀层。研究了镀液中ZrO_(2)颗粒浓度对复合镀层中ZrO_(2)颗粒含量以及复合镀层表面形貌、相结构、硬度、耐磨性能和耐腐蚀性能的影响。结果表明:随着镀液中ZrO_(2)颗粒浓度从5 g/L增加至30 g/L,ZrO_(2)颗粒含量呈现先升高后降低趋势,复合镀层的形貌特征发生变化,导致硬度、耐磨性能和耐腐蚀性能存在差异,但不同复合镀层的相结构无明显差异,都含有单质Zn、Ni_(5)Zn_(21)和ZrO_(2)相。镀液中ZrO_(2)颗粒浓度为20 g/L时,复合镀层中ZrO_(2)颗粒含量达到10.43%,该复合镀层的晶粒细小且结合紧密,表现出良好的致密性,硬度达到503.5 HV,平均摩擦系数和磨损失重仅为0.48和3.42 mg,电荷转移电阻和低频端阻抗值分别达到6.34×10^(3)Ω·cm^(2)和6.84×10^(3)Ω·cm^(2),其性能与Zn-Ni-P合金镀层相比显著提高。适当增加镀液中ZrO_(2)颗粒浓度有利于提高复合镀层中ZrO_(2)颗粒含量,使复合镀层的晶粒明显细化且致密性改善,具有较强的阻碍局部塑性变形和承载能力,并且能有效抑制电化学腐蚀,从而表现出更好的性能。

Ni-SiO_(2)复合镀层电沉积制备及组织性能研究

利用直流电沉积方法在Zr-4合金表面制备了Ni-SiO_(2)复合镀层,采用场发射扫描电镜、显微硬度计、电化学工作站、摩擦磨损试验机等研究复合镀层的表面形貌、显微硬度、耐腐蚀性及摩擦磨损性能。研究结果表明:与单一的Ni镀层相比较,Ni-SiO_(2)复合镀层的显微硬度值有所提升,表面更为均匀,Ni-SiO_(2)复合镀层的耐腐蚀性能和耐磨性能也得到明显提升。且当SiO_(2)颗粒添加量为10 g/L时,复合镀层的综合性能较优。

Preparation and performance of electrodeposited Ni-TiB_2-Sm_2O_3 composite coatings

Sm2O3 and TiB2 were used as codeposited particles in electrodeposition Ni-TiB2-Sm2O3 composite coatings to improve its performance. Ni-TiB2-Sm2O3 composite coatings were electrodeposited in the nickel sulfate,hexadecylpyridinium bromide and cetyltrimethylammonium bromide solution containing TiB2 and Sm2O3 particles. The content of codeposited Sm2O3 in the composite coating was controlled by changing the concentrations of Sm2O3 particles in the solution. The composite coatings were characterized with X-ray diffraction(XRD) and inductively coupled plasma-atomic emission spectrometer(ICP-AES) . The effects of Sm2O3 content on microhardness,wear weight loss and friction coefficient of composite coatings were investigated,respectively. The microhardness of the Ni-TiB2-Sm2O3 composite coatings was 19.35%,16.58%,2.03% higher than that of the Ni coating,Ni-Sm2O3 and Ni-TiB2 composite coatings,respectively. The wear weight loss of the Ni-TiB2-Sm2O3 composite coatings was 7,2.33,1.22 times lower than that of the Ni coating,Ni-Sm2O3 and Ni-TiB2 composite coatings,respectively. The friction coefficient of the Ni coating,Ni-Sm2O3,Ni-TiB2 and Ni-TiB2-Sm2O3 composite coatings were 0.712,0.649,0.850 and 0.788,respectively. The loading-bearing capacity and the wear-reducing effect of the Sm2O3 particles were closely related to the content of Sm2O3 particles in the composite coatings.

齿轮钢电沉积Ni-W/MoS_(2)自润滑复合镀层及性能研究

采用电沉积工艺在制造齿轮常用的40Cr钢表面制备掺杂MoS_(2)颗粒的Ni-W/MoS_(2)自润滑复合镀层,并研究MoS_(2)颗粒对复合镀层表面形貌、晶相结构、显微硬度和耐磨性能的影响。结果表明:Ni-W/MoS_(2)自润滑复合镀层完整覆盖40Cr钢表面,主要成分为Ni、W、Mo和S元素,存在4个Ni的衍射峰并且都呈现(220)晶面择优取向。镀液中MoS_(2)颗粒质量浓度变化导致镀层的晶粒形态及致密性显现出差异,MoS_(2)颗粒含量呈现先升高后降低趋势,造成显微硬度先增大后减小,耐磨性能先改善后变差。当镀液中MoS_(2)颗粒质量浓度为5 g/L,Ni-W/MoS_(2)复合镀层中MoS_(2)颗粒含量达到4.17%,形成条状与乳突状不同形态的晶粒,结合更紧密,其硬度达到607.5 HV,表面磨痕宽度仅为420μm,表现出良好的耐磨性能,能起到较理想的减摩作用,从而显著提高40Cr钢的耐磨性能。

CeO2对激光熔覆TiCp/Ni基复合涂层的影响

利用5kWCO2激光器在A3钢表面激光熔覆添加不同CeO2含量的TiCp/Ni复合涂层。研究了稀土氧化物对激光熔覆金属陶瓷复合涂层的组织结构与性能的影响。结果表明,预涂覆复合合金粉末中添加0.4%CeO2能减少涂层的气孔、疏松,使涂层的组织致密及涂层中TiC颗粒细小光滑,分布均匀,复合涂层的耐磨性与耐蚀性得到显著提高。

电沉积Ni基合金及其复合镀层在10%H_2SO_4中的腐蚀磨损特性研究

采用电刷镀技术制取了Ni—W—Co合金镀层和Ni—W—Co/SiCp复合镀层,利用扫描电镜、能谱仪、X射线衍射仪分别对镀层原始状态及其腐蚀磨损过程中的组织形貌、成分、和相组成进行了观察、分析。研究了在不同的载荷和速度条件下两种镀层的腐蚀磨损特性及腐蚀磨损的协同作用。结果表明:本实验条件下,在较低的载荷和速度下,复合镀层的耐腐蚀磨损性能优于合金镀层,随着载荷和摩擦速度的增大,复合镀层的耐腐蚀磨损性能下降较合金镀层快。

溶胶增强的化学Ni-P-SiO_2复合镀层

采用在基础Ni-P镀液中直接加入溶胶SiO_2的新形式,结合溶胶-凝胶法和化学镀方法,于45钢基材表面成功制备了均匀的复合Ni-P-SiO_2镀层,对比研究了复合镀层与基础Ni-P镀层的显微组织结构、耐磨及耐腐蚀性。结果表明,加入溶胶SiO_2所制备的复合镀层较Ni-P镀层具有更加均匀、致密的显微形貌。当SiO_2溶胶加入量为2.1×10^(-3) mol/L、煅烧温度为400℃时,复合镀层具有最高显微硬度值668.54 HV_(0.025),最低摩擦系数0.279,最正腐蚀电位-0.449 7 V及最小腐蚀电流0.632 7×10^(-6) A·cm^(-2)。说明以该方法所制备的复合Ni-P-SiO_2镀层具有良好的耐磨、耐腐蚀性能,节省SiO_2原料用量,且不需要额外加入分散剂与稳定剂,减少长时间搅拌的能耗,对实际工业生产大有裨益。

Al_(2)O_(3)在等离子喷涂涂层中的应用综述

Al_(2)O_(3)作为等离子喷涂的常用材料,以其良好的耐磨性和耐腐蚀性能被广泛地应用于工业领域。本文从原始喂料特征、第二相粉体粒子等方面阐述其对涂层性能的影响,并从梯度涂层、多层涂层和后处理(封孔处理、激光重熔等)等角度,对涂层的孔隙率和耐腐蚀性能的影响作了详细说明,在涂层的韧性方面,主要分析第二相粒子和热处理对涂层韧性的影响,最后对用等离子喷涂技术制备综合性能良好的Al_(2)O_(3)基复合涂层的研究方向提出了展望。

45钢电沉积Co-W-P/MoS_(2)复合镀层的耐磨性能研究

为提高Co基镀层的耐磨性能拓宽其应用范围,通过电沉积将具有自润滑减摩特性的MoS_(2)颗粒引入Co-W-P镀层。研究了MoS_(2)颗粒质量浓度对Co-W-P/MoS_(2)复合镀层的表面形貌、物相结构、硬度和耐磨性能的影响。结果表明:MoS_(2)颗粒质量浓度为5 g/L时制备的复合镀层表面结构致密,晶粒形态为胞状晶粒,表面存在细长条晶粒,物相为fccCo、hcp-Co和Co_(3)W相,硬度为594.6HV,且耐磨性能较好,稳定摩擦因数为0.32。MoS_(2)颗粒参与共沉积导致复合镀层趋向瞬时成核,进入Co晶格间隙引起晶格畸变,利于晶粒细化,增大复合镀层的硬度。嵌埋在复合镀层中的MoS_(2)颗粒在摩擦过程中易分层断裂,转移到摩擦副接触面形成固体润滑膜起减摩作用,增强复合镀层的耐磨性能。

复合电沉积陶瓷颗粒增强金属基复合涂层研究进展

根据国内外对复合电沉积制备陶瓷颗粒增强金属基复合涂层研究结果,对复合电沉积的基本概念、机理以及复合电沉积方法主要分类进行了归纳和概述,对耐磨、耐蚀和抗高温氧化陶瓷颗粒增强金属基复合涂层进行了分类讨论,重点综述了其组织结构和性能特点及其影响规律等。在此基础上,对复合电沉积陶瓷颗粒增强金属基复合涂层发展前景进行了展望。

SiC颗粒尺寸对镍基复合镀层耐磨性和耐蚀性的影响

在正交实验基础上,对比研究微米SiC(平均粒径1.5μm)和纳米SiC(平均粒径20nm)增强复合镍基镀层的摩擦磨损行为和耐腐蚀性能。通过TEM、SEM、EDX和XRD等手段研究颗粒分散状态以及复合镀层的表面和截面形貌、成分及相结构。采用球-盘滑动摩擦磨损试验机研究复合镀层的耐磨性。电化学阻抗谱测量在3.5%的NaCl水溶液中进行。结果表明:微米级颗粒增强复合镀层可以获得更高的表面硬度,两种增强复合镀层具有相似的摩擦磨损行为。电化学阻抗谱分析表明:SiC颗粒的加入可以提高镀层的耐腐蚀性,且纳米颗粒复合镀层具有更好的耐蚀性。

电沉积RE-Ni-W-B-SiC复合镀层的性能

研究了ＲＥ－Ｎｉ－Ｗ－Ｂ－ＳｉＣ复合材料的耐磨性和耐蚀性．结果表明，在适当的镀液组成及工艺条件下，可获得组成为ＲＥ－Ｎｉ－Ｗ－４８％Ｂ－１５％ＳｉＣ的复合材料镀层．在镀液中加入少量稀土，能提高复合镀层的硬度和耐磨性；热处理温度对复合材料镀层的硬度和耐磨性有较大的影响，硬度和耐磨性随热处理温度的升高而增加．当热处理温度达到４００℃时，复合镀层的硬度达到最佳值，耐磨性在５００℃时为最好．磨损实验表明，在相同条件下，复合材料镀层的耐磨性是硬铬的４～５倍；腐蚀实验表明，复合材料镀层在各种腐蚀介质（硝酸除外）中的耐蚀性均优于１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢．

液体微胶囊复合电沉积铁-磷合金的研究

讨论了用水相分离法进行液体微胶囊的制备技术,并且将以有机硅树脂为囊心的液体微胶囊加入到Fe P合金镀液中进行复合共沉积,得到了含有液体微胶囊的复合镀Fe P合金层。通过对这种复合镀层的耐腐蚀性、耐磨性进行测定,结果证实由于微胶囊加入使得Fe P复合镀层的耐腐蚀性和耐磨性有很大提高。

纳米复合镀层的研究历程

总结了纳米复合镀层的研究结果,纳米复合镀层具有硬度高、耐磨损和耐腐蚀的特性,一些纳米复合镀层还具有自润滑性、光催化活性、良好的电接触性及耐高温等性能。纳米复合镀层的基体材料主要是金属镍,还有铜和锌等。纳米粒子材料包括SiC、SiO2、CeO2、金刚石、碳纳米管、Al2O3、Si3N4、TiO2、PTFE、MoS2、WS2、石墨、ZrO2、La2O3、Cr、Ag及Si微粒等。目前,纳米复合镀层的制备技术还不成熟,需要进行更深入的研究。

工艺条件对电沉积RE-Ni-W-P-SiC-PTFE复合镀层性能的影响

研究了电流密度、镀液温度、pH值和PTFE等对电沉积RE Ni W P SiC PTFE复合镀层性能的影响。结果表明 ,镀态下镀层的硬度在 42 0～ 5 5 0Hv之间 ,当镀液中PTFE浓度为 2 5ml/L时 ,磨损量最小 ,但镀层的耐蚀性却最差 ;而当镀液中PTFE浓度为 30ml/L时 。