碳靶电流对磁控溅射Cp/AlSn复合镀层显微结构的影响（英文）

采用非平衡磁控溅射离子镀技术,当碳靶电流在0.2~.0.8 A范围,在Al Zn4.5Mg轴承合金和单晶硅Si(100)表面制备Cp/Al Sn复合镀层。通过X射线衍射(XRD),扫描电子显微镜(SEM)以及X射线光电子能谱(XPS)分别对复合镀层的相组成,微观形貌及化学态进行表征。结果表明:复合镀层为等轴晶结构;其相组成主要为均匀分布的铝、锡和碳3种相;X射线光电子能谱分析表明,在Cp/Al Sn复合镀层中,铝和锡2种元素主要以单质形态存在,碳元素以sp2和sp3 2种杂化形式存在,其中以sp2杂化为主。     

锌粉颗粒形状对机械沉积无结晶镀层结构的影响

以球状锌粉和片状锌粉为原始锌粉借助于机械镀工艺制备了无结晶锌防护层,运用光学显微镜(OM)、扫描电子显微镜(SEM)观察了镀层的结构形貌;采用XRD技术分析了镀层的物相组成;采用贴滤纸法进行了镀层的孔隙率测试.研究结果表明,片状锌粉制备的镀层比球状锌粉制备的镀层表面要平滑、光亮.球状锌粉制各的镀层中锌粉颗粒呈紧密堆积,部分锌粉颗粒发生塑性变形;片状锌粉制备的镀层中的锌粉颗粒呈层片状叠加,镀层中锌粉颗粒没有发生明显塑性变形.两种形状锌粉制备的镀层均为锌基多相混合体系,镀层中没有固溶体、化合物等合金相产生,属于锌基复合镀层.锌粉颗粒形状对镀层中颗粒之间的结合机理没有显著影响,两种镀层中锌粉颗粒间均以机械咬合为主.     

锌粉颗粒形状对机械沉积无结晶镀层结构的影响

以球状锌粉和片状锌粉为原始锌粉借助于机械镀工艺制备了无结晶锌防护层，运用光学显微镜（OM）、扫描电子显微镜（SEM）观察了镀层的结构形貌；采用XRD技术分析了镀层的物相组成；采用贴滤纸法进行了镀层的孔隙率测试。研究结果表明，片状锌粉制备的镀层比球状锌粉制备的镀层表面要平滑、光亮。球状锌粉制备的镀层中锌粉颗粒呈紧密堆积，部分锌粉颗粒发生塑性变形；片状锌粉制备的镀层中的锌粉颗粒呈层片状叠加，镀层中锌粉颗粒没有发生明显塑性变形。两种形状锌粉制备的镀层均为锌基多相混合体系，镀层中没有固溶体、化合物等合金相产生，属于锌基复合镀层。锌粉颗粒形状对镀层中颗粒之间的结合机理没有显著影响，两种镀层中锌粉颗粒间均以机械咬合为主。     

La_2O_3/CeO_2颗粒尺寸对Ni-La_2O_3/CeO_2复合电镀层高温氧化性能的影响(英文)

通过向普通硫酸镍电镀液中添加一定含量的微米或纳米La2O3/CeO2颗粒,采用复合电镀制备微米或纳米La2O3/CeO2颗粒分布的Ni基复合镀层,并研究La2O3/Ce O2颗粒尺寸对Ni-La2O3/CeO2复合镀层在1000°C抗氧化性能的影响。结果表明:与普通Ni镀层相比,Ni-La2O3/CeO2复合镀层中的La2O3/Ce O2颗粒通过溶解扩散进入氧化膜中,阻碍Ni的外扩散,从而降低氧化速度;此外,与La2O3/CeO2纳米颗粒相比,La2O3/Ce O2微米颗粒在氧化初期还起到扩散障碍层的作用,对阻碍Ni的外扩散具有更强的作用。     

La2O3/CeO2颗粒尺寸对Ni-La2O3/CeO2复合电镀层高温氧化性能的影响（英文）

通过向普通硫酸镍电镀液中添加一定含量的微米或纳米La2O3/CeO2颗粒,采用复合电镀制备微米或纳米La2O3/CeO2颗粒分布的Ni基复合镀层,并研究La2O3/Ce O2颗粒尺寸对Ni-La2O3/CeO2复合镀层在1000°C抗氧化性能的影响。结果表明:与普通Ni镀层相比,Ni-La2O3/CeO2复合镀层中的La2O3/Ce O2颗粒通过溶解扩散进入氧化膜中,阻碍Ni的外扩散,从而降低氧化速度;此外,与La2O3/CeO2纳米颗粒相比,La2O3/Ce O2微米颗粒在氧化初期还起到扩散障碍层的作用,对阻碍Ni的外扩散具有更强的作用。     

稀土Ce对化学镀Fe-P合金镀层成分和形貌的影响

借助电化学分析仪、电子能谱仪、扫描电镜等对稀土掺杂化学镀Fe-P镀层的阴极极化曲线、镀层化学组成和表面形貌进行了分析和测试。结果表明,镀液中加入稀土Ce使得Fe-P合金镀层的极化度减小,析出电位正移;随着镀液中稀土Ce加入量的增加,镀层中的Fe含量减小、P含量先增加后减少;镀层表面由不规则条索状物构成,稀土添加可使表面条索状物尺寸减小、细化。     

湿法超声机械镀锌层的结构分析

采用湿法超声机械镀锌设备制备了机械镀锌层。采用金相显微镜、扫描电子显微镜(SEM)及其配备的能谱仪分析了镀锌层的结构形貌和化学成分;采用贴滤纸法对镀层进行孔隙率测试。结果表明,制备的镀锌层无贯穿性孔隙;镀层主要由锌、少量的锡和铁构成,锌粉颗粒是镀层的主体。部分锌粉颗粒发生团聚;镀层表面细腻、均匀、平整,无凹凸不平结构。     

工艺参数对Ni-纳米La2O3复合电沉积的影响

在氨基磺酸镍镀液中加入La2O3纳米颗粒,制备了Ni 纳米La2O3复合镀层.利用正交试验法研究了微粒悬浮量、电流密度、搅拌速度、温度等工艺参数对复合电沉积的影响,并用扫描电子显微镜对复合镀层的表面形貌进行了分析.结果表明,La2O3颗粒悬浮量对复合镀层La2O3共沉积量的影响最大;复合镀层中La2O3颗粒共沉积量越大、电流密度越小,其表面越平整、组织越致密.     

机械镀Zn-Cu复合镀层的组织结构

为获得防腐-装饰双重效果,采用机械镀的方法首先在钢铁基体表面沉积锌层,然后在锌层表面沉积铜层,最终在钢铁基体表面获得了Zn-Cu复合镀层。采用划线划格法检测分析了镀层的结合强度,采用金相显微镜(OM)、扫描电子显微镜(SEM)观察分析了镀层的组织结构,采用能谱仪(EDS)分析了镀层截面的化学成分及分布。结果表明,机械镀Zn-Cu复合镀层表面平整、光滑,镀层覆盖完整;镀层和基体结合牢固,划线划格时镀层无翘起或脱落现象,镀层内部无分层脱落现象。复合镀层由外层的铜层和内层的锌层组成,外层铜层由片状铜粉层叠构成,内层锌层由锌粉颗粒堆积而成。外层铜层和内层锌层之间存在明显的界线,无合金过渡层存在,两者之间为机械结合;内层锌层和基体之间存在明显的界线,无合金过渡层存在,两者之间为机械结合。     

稀土相RE-Sn表面Sn晶须的生长规律

将稀土相CeSn3、LaSn3、(La0.4Ce0.6)Sn3及ErSn3暴露于空气中,研究在时效处理过程中其表面Sn晶须的生长规律。结果表明:室温时效过程中,在稀土相的表面均出现了Sn晶须的生长现象,且稀土相LaSn3的表面倾向于形成包状和扭结状的Sn晶须,稀土相CeSn3和(La0.4Ce0.6)Sn3的表面倾向于形成针状和扭结状的Sn晶须,而稀土相ErSn3的表面倾向于形成大尺寸的杆状和棒状Sn晶须。150℃时效过程中,稀土相CeSn3、LaSn3和(La0.4Ce0.6)Sn3的表面没有出现Sn晶须的生长现象,而稀土相ErSn3的表面出现了大量的小尺寸线状Sn晶须。综上所述,稀土相的氧化倾向决定了其表面Sn晶须的生长规律。     

Electrodeposition of zinc and composite zinc–yttria stabilized zirconia coatings

Pure zinc and composite coatings of zinc and nano-sized yttria stabilized zirconia (YSZ) particles were prepared by cathodic electrodeposition from zinc sulphate-based electrolytes containing gelatin. The effects of gelatin on the morphology, crystallographic orientation of the zinc coatings and deposition mechanism of the composite Zn–YSZ coatings were studied. The coatings obtained were studied by scanning electron microscopy (SEM) with energy dispersion spectroscopy (EDS), X-ray diffraction and potentiodynamic polarization measurements. It was shown that the addition of gelatin to the electrolyte significantly changed the microstructure and crystallographic orientation of the zinc deposits and improved the coating microhardness. In the case of the composite coating co-deposition process, the YSZ particles were found to preferentially rest on the edges or macrosteps of the deposited zinc crystals. The incorporation of YSZ particles into the composite coating was enhanced by reducing the solution pH and through the addition of gelatin. The mechanical and electrochemical properties of conventional zinc coatings were observed to be significantly improved by the incorporation of YSZ particles.     

纳米植酸锌缓蚀效果及其复合环氧涂层的防护性能

目的 考察NaCl溶液中植酸锌对Q235的缓蚀效果及其复合环氧涂层的防护性能。方法 以植酸钠和乙酸锌为原材料成功制备纳米植酸锌,并通过红外光谱仪（IR）、扫描电子显微镜（SEM）、电子能谱仪（EDS）、透射电子显微镜（TEM）及X射线衍射仪（XRD）对其结构及形貌进行表征。采用开路电位、极化曲线、X射线光电子能谱技术（XPS）及SEM等手段,研究了Q235在含植酸锌浸出物的Na Cl溶液中的腐蚀行为及腐蚀形貌。利用SEM、电化学阻抗谱（EIS）以及盐雾测试等方法,研究了纳米植酸锌在环氧涂层中的分散性及其对环氧涂层防腐蚀性能的影响。结果 SEM和TEM显示合成的植酸锌为球形颗粒,颗粒直径较为均匀,为20～40 nm。开路电位、极化曲线测试显示,纳米植酸锌浸出物可以抑制Q235在1%NaCl溶液中的腐蚀。XPS显示,Q235试样表面明显吸附植酸根成膜。纳米植酸锌在环氧树脂中的分散状态良好,无明显团聚现象。EIS和盐雾测试显示,纳米植酸锌可以增强环氧涂层的防护性能。结论 纳米植酸锌可以用作防锈颜料,且相比于磷酸锌防锈颜料,添加相同量的纳米植酸锌的涂层的防腐效果更佳,其可能和植酸锌的小尺寸、良...     

RuO2包覆的TiO2纳米复合粒子的表面与界面分析

将溶胶-凝胶法与水热合成技术相结合制备了RuO2包覆量为1.5%的TiO2纳米复合粒子,并采用X射线衍射(XRD)、原子力显微镜(AFM)、傅立叶变换红外光谱(FT-IR)及X射线光电子能谱(XPS)详细研究了纳米复合粒子的表面与界面性质.结果表明,RuO2以非晶态高度分散在TiO2纳米粒子表面形成包覆层,TiO2的晶型为锐钛矿型;纳米复合粒子呈球形,平均粒径约为47.5nm,RuO2包覆层的平均厚度约为0.75nm;RuO2包覆层与核材料TiO2纳米粒子表面存在化学键的作用,这种化学包覆有利于提高纳米复合粒子结构和性能的稳定性.     

Characterization of calcium-modified zinc phosphate conversion coatings and their influences on corrosion resistance of AZ31 alloy

Two kinds of phosphate conversion coatings, including zinc phosphate coating and zinc-calcium phosphate coating, were prepared on the surface of AZ31 alloy in phosphate baths. The morphologies of these coatings were observed using scanning electron microscopy. Their chemical compositions and structures were characterized using energy-dispersive X-ray spectrum, X-ray photoelectron spectroscopy and X-ray diffraction. The corrosion resistance of the coatings was evaluated by potentiodynamic polarization technique. The results show that the flowerlike Zn-Ca phosphate conversion coatings are mainly composed of hopeite (Zn₃(PO₄)₂·4H₂O). They have a quite different morphology from the dry-riverbed-like Zn phosphate coatings that consist of MgO, MgF₂, Zn or ZnO and hopeite. Both of the zinc and zinc-calcium phosphate coatings can remarkably reduce the corrosion current density of the substrates. The Zn-Ca coating exhibits better corrosion resistance than the Zn coating. Introduction of calcium into the phosphate baths leads to the full crystallinity of the Zn-Ca coating.     

锌液中Al含量对440MPa级高强IF钢镀层的组织结构及抑制层的影响

应用SEM和EDS研究了锌液中不同Al含量对镀层组织结构和抑制层的影响,进而确定440MPa级高强IF钢镀层成形性的最佳Al含量。结果表明,随着锌液中Al含量的增加,纯锌层与基体界面处ζ相明显减少,Al的富集程度增加,抑制层的晶粒逐渐长大,致密性增加。当锌液中Al含量为0.25%时,镀层成形性最好。     

Combination of zinc alloy coating with thin plasma polymer films for novel corrosion protective systems on coated steel

Steel sheet used in automotive applications has to be corrosion protected effectively, which is usually realized by zinc or zinc alloy coatings with a thickness range of 5–10 μm. Steel sheet for areas of a car body which are exceptionally stressed by corrosion, e.g. cavity flanges or joints, may be protected additionally by a thin weldable organic coating with a thickness of 2–4 μm. A very promising approach to a significantly reduced use of resources is the combination of zinc alloy coatings with thin plasma polymer films deposited by means of plasma-enhanced chemical vapour deposition (PECVD). Such plasma polymer films of just a few 100 nm thickness show excellent barrier and adhesion properties as well as a high mechanical stability.Within this work thin plasma polymer films were deposited on zinc alloy coated steel substrates using the strip hollow cathode (SHC) method, which was modified for application on grounded substrates. A pulsed DC glow discharge in a mixture of argon and an organosilane precursor was used for the deposition of films with a thickness of 100–500 nm.The chemical compositions of the coatings were determined by means of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The morphologies of the coating systems were studied by means of scanning electron microscopy. The performance of the coating systems has been studied in different specific tests of corrosion and processing behaviour. The investigated coating systems show a corrosion resistance comparable to reference samples of electro-galvanised steel sheet with additional organic coating even with a coating thickness less of half of the reference samples.     

Electroless Ni-Co-P Coating of Cenospheres Using Ag(NH_3)_2~+ Activator

FLY ASH CENOSPHERES are primarily a by-productin power generation plants.Research is in progress toeffectively use this by-product to produce new usableand profitable materials as they pose major disposaland environmental problems.Fly ash cenospheres areunique,property stable,non-toxic,non-metallic hollowmicro-particles.Due to the unique hollow structure andphysical mechanics properties,Cu^Ag and other metalsare often coated on cenospheres to produce lightweightmetal matrix composites,w…     

Effect of SiO2:Na2O molar ratio of sodium silicate on the corrosion resistance of silicate conversion coatings

Passivation treatment by sodium silicate solution is considered as an alternative to chromium chemical conversion treatment to improve the corrosion resistance of hot-dip galvanized (HDG) steels. In this paper, a transparent silicate coating was formed on the surface of HDG steel by immersing in sodium silicate solution with SiO₂:Na₂O molar ratio in the range from 1.00 to 4.00. The parameter about the SiO₂:Na₂O molar ratio of silicate solution has been discussed using corrosion resistance and surface morphology. Tafel polarization, electrochemical impedance spectroscopy (EIS) measurements and neutral salt spray (NSS) test show that silicate coatings increase the corrosion resistance of HDG steels. From the results obtained, it is deduced that the optimum SiO₂:Na₂O molar ratio is 3.50. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction analysis (XRD), and reflectance absorption infrared spectroscopy (RA-IR) show that there are no obvious differences of the chemical composition and structure in various silicate coatings. The silicate coatings mainly consist of zinc oxides/hydroxides, zinc silicate and SiO₂. However, atomic force microscopy (AFM) images reveal that the surface of silicate coatings with a molar ratio of 3.50 is more compact and uniform than other silicate coatings.     

Electrodeposition of zinc on AZ91D magnesium alloy pre‐treated by stannate conversion coatings

A stannate chemical conversion process followed by an activation procedure was employed as the pre‐treatment process for AZ91D magnesium alloy substrate. Zn was electroplated onto the pre‐treated AZ91D magnesium alloy surface from pyrophosphate bath to improve the corrosion resistance and the solderability. The surface morphologies of conversion coating and zinc coating were examined with scanning electron microscope (SEM). The phase composition of conversion coating was investigated by X‐ray diffraction (XRD). The electrochemical corrosion behavior of the coatings in the corrosive solution was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The experimental results showed that the activated stannate chemical conversion coating provided a suitable interface between zinc coating and the AZ91D magnesium alloy substrate. The corrosion resistance of the AZ91D substrate was improved by the zinc coating.     

Ti纳米粒子对环氧涂层防护性能的影响

应用电化学阻抗法(EIS)、示扫描量热法(DSC)、X射线光电子谱(XPS)研究了添加Ti纳米粒子对环氧涂层防护性能的影响.结果表明:添加Ti纳米粒子可以提高环氧涂层的防护性能,添加量在0.5%(以w/w计)时最好.这是由于添加Ti纳米粒子虽然可增加涂层孔隙率,但Ti纳米粒子与环氧树脂之间存在的相互作用可改善涂层对腐蚀性介质的屏蔽性能,提高涂层的防护性能.