Mechanical and anticorrosive properties of copper matrix micro- and nano-composite coatings

In the frame of the research domain of the production of metal matrix composite coatings, the aim of the present work was the production of copper electrodeposits containing micro- and nano-particles of SiC. The electrodeposition was carried out under dc conditions using a copper pyrophosphate plating bath into which micro- or nano-SiC particles were suspended. The composite coatings were tested and compared to pure copper coatings regarding their microstructure, mechanical and anticorrosive properties.The codeposition of SiC in the metal matrix changed the microstructure of the copper leading to improvement of both their mechanical and, in some cases, their protective properties. The Vickers microhardness presented an increase of about 35% and 61% in the case of SiC micro- and nano-particles incorporation while the increase of the abrasion resistance was 88% and 58%, respectively.The incorporation of the micro-particles lead to gaps formation among the SiC micro-particles and the metal matrix, thus lowering the resistance on both uniform and localized corrosion in comparison to the pure copper-coated specimens while the codeposition of SiC nano-particles produced deposits with higher resistance to both uniform and localized corrosion.     

Synthesis and characterization of Ni-W/TiN nanocomposite coating with enhanced wear and corrosion resistance deposited by pulse electrodeposition

To enhance mechanical properties and anti-corrosion capability of Ni-W alloy further, Ni-W/TiN nanocomposite coating has been co-deposited via pulse current co-deposition in this work. The effects of TiN nanoparticles and operating parameters on the structure and properties of the deposited coating were examined. It illustrated that the nanocomposite coatings are uniform, dense and crack-free, exhibiting dome-like or hill-valley like structure. The particles were homogeneously incorporated in the metallic matrix. RTC analysis indicated that the preferred orientation of Ni-W/TiN was (111) texture. The crystallite size was of 10–16 nm, indicating the formation of nanocrystalline structure. TiN concentration, duty cycle and frequency could influence the amount of TiN particle and W element in the coating, then regulating hardness and anti-wear behaviors. The low duty cycle and long deposition time could diminish the roughness of the coating. The inclusion of TiN nanoparticles in the nickel matrix could promote the nucleation of fresh nickel crystals and restrict the growth of already formed nickel grains, favoring the homogeneous growth and grain refinement of Ni-W crystals. The doped TiN particles would favor the preferred orientation (111) plane, enhanced the hardness, wear and corrosion resistance of Ni-W alloy. Electrochemical results illustrated that the best corrosion-resistant properties of the nanocrystalline coating could be obtained at TiN 30 g L⁻¹, duty cycle of 20% and frequency of 60–200 Hz. The enhanced mechanical properties and corrosion resistance of Ni–W/TiN coating benefits its application in harsh corrosive environment.     

Effect of BEO in the electrodeposition process of Ni/diamond composite coatings for preparation of ultra-thin dicing blades: Experiments and theoretical calculations

Ni/diamond dicing blades is the main tool for scribe of silicon wafer at present. In order to decrease the width of dicing slot on the wafer, it is necessary to reduce the thickness of blades, and to increase the hardness, toughness and wear resistance of the Ni/diamond composite coatings in the process of electrodeposition. In this paper, 1,4-bis(2-hydroxyethoxy)-2-butyne (BEO) was used as an organic additive in the composite baths containing nickel amino-sulfonate, nickel chloride, boric acid, sodium dodecyl sulfate (SDS) and diamond particles in sizes of 3–5?µm, in order to improve the properties of Ni/diamond coatings and produce ultra-thin Ni/diamond dicing blades. The textures of Ni/diamond composite coatings were mainly Ni (200) and Diamond (111) since the addition of BEO in the baths inhibited the growth of Ni (111) and Ni (220). Quantum chemical calculations and molecular dynamics (MD) simulations showed that BEO could adsorb at the nickel surface strongly and inhibit the electrodeposition of nickel atoms. With the increase in concentration of BEO in the baths, the cathodic polarization potentials shifted to more negative direction and the thicknesses of the coatings decreased. Adding the appropriate amount of BEO (0.1–0.2?g/L) in the baths, the roughness of the coating decreased the number of individual diamond particles in the coating increased, and the hardness and the wear resistance of the coating was improved. When the thickness of Ni/diamond composite coating on aluminum alloy wheeled substrate was 15?µm, the width of its dicing slot was 22?µm. However, the addition of BEO in the bath cannot change the adhesive wear mechanism of the coating.     

Self-repairing coating for corrosion protection of aluminum alloys

The development of effective anticorrosion pre-treatments for metallic substrates is an issue of great importance for durability of metal structures and components. In this work, we proposed and demonstrated the concept of self-repairing coating for corrosion protection of aluminum alloys, using cagelike oil core/silica gel shell particles. These micron-scale, cagelike smart microspheres with opened and closed pores were successfully fabricated, and at the same time encapsulated repairing agent (methyl methacrylate) and catalysts (potassium persulfate and sodium thiosulfate) into the microspheres, respectively. Such smart particle composites (SPCs) were prepared based on an interfacial self-assembly process and sol–gel reaction. They were then self-assembled on the AA2024 aluminum alloy surface, followed by the application of a sol–gel film. The hybrid film worked as a primer coating featuring the self-repairing property. Both the EIS and SEM/EDS data demonstrated that the encapsulated repairing agent was released as a response to external stimulus (scratches) and polymerized to repair the coating defects. By comparing the corrosion rate of AA2024 in three coating systems, the self-repairing effect is quantified to be 22% after 2 h immersion in deoxidized 3% NaCl solution.     

Effective electrodeposition of poly(3,4-ethylenedioxythiophene)-based organic coating on metallic food packaging for active corrosion protection

Journal of Applied Electrochemistry - Modern technologies continuously need special materials with specific properties to adopt the desired application. Recently, numerous researches have been...     

On the corrosion protection properties of fluoropolymer coatings

Fluoropolymers have attained great importance as coating materials because of their excellent resistance to high temperature, chemicals and organic solvents. Electrochemical impedance spectroscopy was used to study the corrosion protection properties both on undamaged fluoropolymer coatings and on samples with an artificial defect. The experimental results were interpreted on the basis of a proposed equivalent electrical circuit which best fits the experimental impedance spectra. In this way we observed the high quality of the fluorinated coatings compared with that of the corresponding hydrogenated polymer used as a reference. The protective properties of the fluoropolymer coatings studied can be related to chemical (fluorine and chlorine functional groups) and physical (good order of the polymeric chains) characteristics of the resins.     

Synthesis and corrosion protection performance of polydiphenylamine

In recent years, the conducting polymers are used in organic coatings as a replacement of chromate based pigments. The effectiveness of polydiphenylamine (PDPA) in the vinyl coating towards the corrosion protection of steel in acidic environment has been found out. The polymer PDPA was synthesized by chemical oxidation of diphenylamine by ammoniumpersulfate in hydrochloric acid medium. The polymer was characterized by FTIR and XRD. The corrosion protection performance of the PDPA containing 0–5% in vinyl coating on steel in 0.1N HCl has been assessed by electrochemical impedance spectroscopy. Coatings containing more than 3% PDPA are found to offer excellent corrosion protection of steel in acid media due to redox property of PDPA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

水轮机用耐磨蚀磨损涂层技术的研究

水轮机的耐磨蚀、耐磨损涂层对延长水轮机的寿命有着重要的作用。总结了现阶段水轮机用保护涂层的技术,着重介绍了改性环氧树脂(EP)非金属涂层的制备及在水电站中的应用,同时对非金属涂层的发展趋势作了展望。     

A modified Damascene electrodeposition process for bottom-up filling of recessed surface features

A modification of the conventional Damascene metallization process is described whereby selective removal of the thin wetting/seed layer from the sidewalls and free surfaces enables selective nucleation and bottom-up electrodeposition of metals and alloys in recessed surface features. The process is demonstrated by filling sub-micrometer trenches with electrodeposited Ni. A conventional PVD Cu seed layer is etched to remove Cu from the sidewalls and free surface while leaving a continuous Cu wetting layer intact on the trench bottom. The underlying non-wetting barrier layer provides a conductive path for electrodeposition from contacts on the perimeter of the work piece to the trench bottom. The robustness of the bottom-up Ni electrodeposition process is greatly increased by the addition of 2-mercaptobenzimidazole (MBI) to the plating bath. The additive hinders spurious nucleation of Ni on residual Cu patches that may remain on the free surface.     

镍/纳米二氧化硅纳米复合镀层耐腐蚀性能的研究

制备了纳米氧化硅镍复合镀层材料,并利用静态浸泡法对纯镍镀层和由镀液中不同微粒含量制备的复合镀层样品的耐蚀性能进行了研究,讨论镀液中纳米微粒含量对镀层抗蚀性能的影响。并用扫描电镜观察镀层的表面形貌。     

TiCN and metallic coatings for corrosion protection of separator plates in MCFCs

Stainless steel 304 substrates were coated with different materials in order to find a suitable coating material for corrosion protection of separator plates in molten-carbonate fuel cells (MCFCs). Five titanium carbonitride coatings differing in composition and morphology and a titanium monoxide coating were deposited with chemical vapour deposition techniques. Also double-layer coatings of TiN/Au and TiN/Ni were prepared. The coatings were tested on their corrosion protection of separator plates in four different environments: under MCFC-cathode or anode gas, at load or at open circuit conditions. The corrosion behaviour was characterized using cyclic voltammetry. Corrosion rates were determined with electrochemical methods and cross-section analyses of corrosion layers. Titanium nitride coatings showed the best corrosion protection. The titanium carbide and titanium monoxide coating showed respectively less and no protection. The thin gold and Ni-coatings were unstable. Under cathode gas, the most important corrosion protection is given by keeping the cell at load, and then a titanium nitride coating might provide lifetime protection. Under anode gas, corrosion is most severe at load conditions. A titanium nitride coating also gives corrosion protection, but not enough for lifetime protection.     

Electrochemical preparation and characterization of Ni/SiC compositionally graded multilayered coatings

In our study, Ni/SiC functionally graded coatings have been obtained by electrochemical deposition of silicon carbide microparticles (mean diameter 2 μm) from nickel Watts baths with different concentrations of SiC particles in solution. The SiC particles were characterized by electroacustics technique in order to determine zeta potential and particle size. Moreover, the effect of the concentration of SiC particles in solution on the amount of SiC deposited in the nickel layer was investigated. Further experiments showed that the degree of particle incorporation provoked changes in the texture of the nickel matrix. The characterization of the coatings proved that the Ni/SiC graded composite coatings were bright and compact, presented good adhesion and improved the hardness and wear resistance of pure nickel electrodeposits.     

电厂除盐水箱聚脲防腐涂层的设计与应用

介绍了电厂除盐水箱的技术参数、所处的腐蚀环境以及聚脲防腐涂层的设计要求。应用验收结果表明,防护涂层外观平整、光滑,顶部厚度1.02 mm,侧面厚度1.56 mm,底部厚度1.52 mm,电火花通过率100%,拉伸强度12.6 MPa,撕裂强度46 kN/m,断裂伸长率260.5%。水箱出水口水质符合要求,除盐水箱使用寿命可达30年。     

纳米改性工业防腐蚀涂料的研制与应用

介绍了纳米改性工业防腐蚀涂料的制备工艺,包括纳米浓缩浆、纳米改性环氧封闭漆、纳米改性环氧云铁中间漆以及纳米改性含氟聚氨酯面漆等系列产品的制备与表征。测试结果表明,纳米材料在纳米浆及涂料中获得了良好分散,纳米改性复合涂层(即喷铝涂层+纳米改性环氧封闭漆+纳米改性云铁中间漆+纳米改性含氟聚氨酯面漆)的物理机械性能以及耐久性均得到显著提高,产品在实际工程应用中也取得了可喜成果。该纳米改性工业防腐蚀涂料具有良好的应用前景。     

化学镀制备高耐蚀耐磨Ni-P-SiC复合镀层

研究了Ni-P-SiC复合镀层的制备工艺和性能以及SiC含量对镀层性能的影响。采用Taber试验机对Ni-P-SiC复合镀层的磨损性能进行了测试,并用VHX-100型三维视频显微镜对磨损形貌进行了观察,分析了复合镀层的磨损机理。结果表明:SiC颗粒的加入能有效地降低摩擦副之间的犁沟效应及摩擦表面发生粘着的面积,从而减少镀层的磨损。采用电化学实验等手段研究了Ni-P-SiC复合镀层的耐蚀性能。当复合镀层均匀一致,能起到一个良好的屏蔽作用时,耐蚀性十分优异;而镀层缺陷的存在将导致耐蚀性能降低。     

Ni-ZrO2复合镀层的腐蚀摩擦学性能研究

用电镀方法制得Ni-ZrO2复合镀层,研究电镀Ni-ZrO2复合镀层的结构以及其硬度、耐磨性、抗腐蚀性与电镀电流密度的关系。结果表明：复合镀层的显微硬度比纯镍镀层硬度成倍提高,复合镀层耐磨性比镍镀层提高20％以上;抗腐蚀性提高70％以上。X射线衍射结果显示,复合镀层由Ni及非晶ZrO2组成。Ni相为面心立方晶体结构,晶格常数为0．353nm,小于纯镍镀层,晶粒尺寸为23．8nm,大于纯镍镀层。     

Application of polyaniline/nylon composites coating for corrosion protection of steel

In this research, we investigated the corrosion inhibition properties of polished steel plates (low carbon) coated with a polyaniline (emeraldine base form) blend with nylon 66 (termed PANi/Ny) via cast method with formic acid as the solvent. Polyaniline (PANi) was prepared chemically from aqueous solution using aniline (0.2 M) as a monomer and ammonium persulfate (0.2 M) as an oxidant. The polymer powder produced was changed into emeraldine base (EB) form after treatment with dilute ammonia solution (0.5 M) in order to do further processing. The corrosion experiments were performed in the open circuit, exposing samples to different aggressive and corrosive conditions (e.g., NaCl, HCl). To produce a good comparison, the corrosion study was performed on both polymer-coated and bare-steel samples. Corrosion monitoring was performed by simple immersion tests and determination of the concentration of iron ions and metal weight loss in test solutions. It was found that PANi/Ny coatings can provide an anodic protection against corrosive environments in which the metals are exposed. The corrosion rate for the polymer coated steel was significantly lower than the bare steel (~10–15 times).     

Fault-tolerant hybrid epoxy-silane coating for corrosion protection of magnesium alloy AZ31

In this work, a hybrid epoxy-silane coating was developed for corrosion protection of magnesium alloy AZ31. The average thickness of the film produced by dip-coating procedure was 14 μm. The adhesion strength of the epoxy-silane coating to the Mg substrate was evaluated by pull-off tests and was found to be higher than 16 MPa both in dry and wet conditions. The hybrid epoxy-silane coating showed high corrosion resistance both when intact and when punched through by a needle. The low frequency impedance of intact coating was higher than 1 GΩ cm² after one month of immersion in 3.5% NaCl solution. Both, artificially induced defects and corrosion sites that appeared on the metal surface did not propagate. Their passivation behavior, that we call fault-tolerance, was observed by EIS, SVET-SIET and SEM-EDS. It was ascribed to the good adhesion, high coating integrity and corrosion inhibiting effect provided by diethylenetriamine used as epoxy hardener.     

Polyaniline‐grafted polyurethane coatings for corrosion protection of mild steel surfaces

We report the superior corrosion‐resistant properties of conducting polyurethane networks of polyaniline (PANI), poly‐m‐aminophenol (PmAP), and poly‐o‐anisidine (PoA) coated on mild steel panels. These networks were prepared by blending conducting polyanilines with isocyanate‐containing prepolyurethanes. Free‐standing polyurethane films were obtained after a moisture cure for several days to ensure complete reaction of the excess isocyanate. The films were electrochemically active with conductivity in the range of 10^?2 to 10^?3 S/cm. The solution blends and formed films were characterized by infrared, ultraviolet, thermogravimetric analysis, and differential scanning calorimetry. Electrochemical corrosion studies of the coated films on mild steel panels showed excellent corrosion protection in the following order: PU‐PANI > PU‐PmAP > PU‐PoA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45806.     

无铬达克罗涂料工艺及耐蚀性能研究

以稀土铈盐为添加剂,用磷酸钝化膜替代铬酐进行无铬达克罗涂料的工艺和性能研究。结果表明,锌铝(质量比为4∶1)290～320 g/L、磷酸80～90 g/L,铈盐1.5～2.0 g/L的配方涂料,在80℃下预烘15 min,然后280℃固化30 min后,可得到优良耐蚀性能的无铬达克罗涂层;电化学法研究显示,铈盐的添加有效降低了涂层的腐蚀电流。