Preparation of anticorrosion hybrid silica sol–gel coating using Ce(NO3)3 as catalyst

In this report, hybrid silica sol–gel coating was prepared using Ce(NO₃)₃ (Sol-Ce) as catalyst. Structure, surface morphology and anticorrosion ability of Sol-Ce solution/coating were studied by infrared spectroscopy (IR), scanning electron microscopy, energy dispersive spectrometer (EDS), potentiodynamic scan (PDS) and electrochemical impedance spectroscopy (EIS). IR results showed that Ce(NO₃)₃ had a stronger influence on reactivity of alkoxysilane. EDS results revealed that the fraction of Fe in Sol-Ce coating was significantly lower than regular acid-catalyzed hybrid silica sol–gel coating (Sol-Ac) and Sol-Ac with Ce(NO₃)₃-doped coating (Sol-Ac/Ce). The results of PDS and EIS demonstrated that Sol-Ce coating had better anticorrosion ability than Sol-Ac and Sol-Ac/Ce on carbon steel. The enhanced anticorrosion performance of the Sol-Ce coating might result from the following two reasons: (a) Ce(NO₃)₃ as a catalyst could alleviate the negative effects of low pH with using acid catalyst (dissolution of carbon steel) and (b) Ce(NO₃)₃ could impede corrosion of carbon steel as corrosion inhibitor.     

Characterization and anticorrosive properties of poly(2,3‐dimethylaniline)/nano‐Al2O3 composite synthesized by emulsion polymerization

Poly(2,3‐dimethylaniline)/nano‐Al₂O₃ composite (PAC) was synthesized by emulsion polymerization using dodecyl benzene sulfonic acid as emulsifier and dopant. The structure of PAC was characterized by Fourier fransformation infrared spectroscopy, UV–visible adsorption spectroscopy, and field emission scanning electron microscopy. The thermal stability was studied by thermogravimetric analysis, and the electrochemical performances were studied by cyclic voltammetry measurements. Epoxy coatings containing PAC and poly(2,3‐dimethylaniline) (P(2,3‐DMA)), respectively, were painted on steel, and accelerated immersion tests were performed to evaluate the anticorrosion property of the coatings in 3.5% NaCl solution. The results showed that the addition of PAC and P(2,3‐DMA) could improve the anticorrosion performance of epoxy coating significantly and the PAC coating had higher corrosion resistance than that of P(2,3‐DMA). Copyright © 2013 John Wiley & Sons, Ltd.     

超疏水性聚苯胺微/纳米结构的合成及防腐蚀性能

以苯胺为单体, 过硫酸铵为氧化剂, 通过改变不同的掺杂剂, 采用"无模板"法合成了具有不同浸润性的聚苯胺微/纳米结构, 并得到超疏水聚苯胺微/纳米结构. 采用红外吸收光谱、 紫外-可见吸收光谱、 X射线衍射及扫描电镜对聚苯胺微/纳米结构及形貌进行了表征, 测定了聚苯胺微/纳米结构的接触角, 并通过Tafel极化曲线和电化学交流阻抗研究了不同疏水性的聚苯胺微/纳米结构在0.1 mol/L H₂SO₄溶液中对碳钢的腐蚀防护作用, 探讨了聚苯胺微/纳米结构的表面浸润性对腐蚀防护性能的影响. 研究结果表明, 随着聚苯胺微/纳米结构疏水性的增强, 对碳钢的腐蚀防护作用增强, 当掺杂剂为全氟辛酸时所制备的超水聚苯胺微/纳米结构表现出最佳的防腐蚀性能(η= 94.70%).     

Potential of zinc based-graphene oxide composite coatings on mild steel in acidic solution

This study introduces varying concentrations of graphene oxide (GO) as a filler into zinc chromate in forming composite coatings to improve the corrosion protection of mild steel. The purity of synthesized GO was inferred through the application of complementary characterization techniques, including FT-IR, XRD, Raman, SEM-EDX, and TEM analyses. GO doped zinc chromate coatings were deposited on the surface of mild steel through the brushing method. Electrochemical studies, i.e., electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) were conducted to elucidate the anticorrosion properties of the coated mild steel exposed to 0.5 ​M HCl solution. It was revealed that the highest anticorrosion protection was attained at low doping amount of 0.5% of GO with a corrosion rate of 0.036 mpy. Surface analyses revealed that incorporating GO into zinc chromate coating can effectively improve the anticorrosion properties and adhesion strength.     

Corn oil based poly(urethane-ether-amide)/fumed silica nanocomposite coatings for anticorrosion application

Poly(urethane-ether-amide) (PUIEtA) nanocomposite coatings on mild steel were prepared by using corn oil, isosorbide and isophorone diisocynate and fumed silica. The syntheses steps were confirmed by FTIR, ¹H NMR and ¹³C NMR spectroscopy techniques. The morphology of PUIEtA nanocomposite coating was studied by SEM-EDX, that confirmed the presence of nanosilica and thermal behavior was studied by DSC/TGA analysis. The anticorrosion performance of PUIEtA coating systems on mild steel, exposed to 3.5?wt% NaCl solution, was evaluated using electrochemical impedance spectroscopy. Scratch hardness, pencil hardness, adhesion, and bending test were performed in order to investigate the performance of nanocomposite coating on mild steel substrate. It was found that PUIEtA-fumed silica nanocomposite coating could provide much better protection than PUIEtA. PUIEtA-3 nanocomposite coating can be safely used up to 200?°C.     

Synthesis of polyaniline‐modified mesoporous‐silica containers for anticorrosion coatings via in‐situ polymerization and surface‐protected etching

An efficient type of container for anticorrosion coating based on polyaniline (PANI) modified mesoporous silica (pS) sphere has been first prepared via in‐situ polymerization and surface‐protected etching. The PANI‐modified containers not only show higher concentration of loaded inhibitor than pS, but also protect steel well because of the PANI. The coating with 1H‐benzotriazole (BTA) loaded containers shows significant anticorrosion property because of the release of BTA from containers. The structure and morphology of container are characterized by FTIR, XRD, SEM and TEM. The release of BTA from pS and PANI‐modified containers is determined by UV in water. The possible self‐healing anticorrosion performances are evaluated by EIS and polarization curves which indicate that the coating including BTA‐loaded containers performs best. The strategy of modifying pS by PANI is effective and successful. Copyright © 2016 John Wiley & Sons, Ltd.     

Improvement of Corrosion Resistance of Metals by an Environmentally Friendly Silica Coating Method

Corrosion resistance of stainless steel and Zn plated steel can be improved by a chromium-free environmentally friendly chemical solution deposition method. Precursor solutions were prepared from tetraethoxysilane with polymer, and were deposited on stainless steel, Zn plated steel and aluminum alloy by dip coating, followed by heat treatment. Addition of polymer to the precursor solution proved very effective in preparing films free from cracks on stainless steel and aluminum alloy substrates. The corrosion resistance was greatly improved by the resulting sub-micron thick silica-polymer hybrid film coatings on stainless steel and on Zn plated steel prepared at 200°C. The hardness of aluminum alloy coated with silica-PMMA hybrid film was improved by 7% over uncoated alloy.     

铝合金表面改性对有机涂层附着力的影响及腐蚀防护性能研究

利用电化学阻抗（EIS）、扫描微参比技术（SRET）、接触角、粗糙度、附着力、盐雾等测试方法,研究了铝合金阳极氧化与贻贝黏附蛋白（MAP）/CeO₂/硅烷γ-APS（MCA）表面复合修饰的腐蚀防护性能以及对改性聚氨酯涂层附着力和耐蚀性的影响。结果表明,MCA复合膜可抑制铝合金的腐蚀,并具有一定的自修复功能;阳极氧化和MCA表面复合修饰可为铝合金提供有效的早期腐蚀防护作用,且能提高铝合金表面粗糙度和润湿性,显著提升改性聚氨酯涂层在铝合金表面的附着力和耐蚀性,因而结合改性聚氨酯涂层和表面复合修饰可实现对铝合金长期有效的腐蚀防护。     

Effect of Aluminum Alloy Surface Modification on Adhesion of the Modified Polyurethane Coating and Its Corrosion Protective Performance北大核心CSCD

The ordinary organic coatings on aluminum alloy usually encounter a problem of low adhesion to the substrate, which results in destruction and failure of the long-term protective performance of the anticorrosion systems. The surface modification of aluminum alloy is able to enhance the adhesion of organic coating on aluminum alloys, and to improve their protective performance. In this work, a combined surface modification of anodic oxidation and mussel adhesion protein/CeO2/3-aminopropyltriethoxysilane composite film (MCA) was developed on the aluminum alloy. The adhesion of modified polyurethane coated on the treated aluminum alloy and its corrosion protective performance were evaluated comprehensively by using contact angle, adhesion strength, electrochemical impedance spectroscopy (EIS), and scanning reference electrode technique (SRET). The measurements of EIS and SRET demonstrated that the MCA composite film on anodic oxidized Al possessed self-healing function and provided effective protection against early corrosion of aluminum alloy. The pull-off test showed that both anodic oxidation treatment and MCA composite film modification were able to increase the adhesion of modified polyurethane coating on aluminum alloy, and their combined action were supposed to remarkably enhance the adhesion strength up to 17.1 MPa. The reason for the improvement of adhesion was that the anodic oxidation treatment and MCA composite film modification could improve the surface roughness of aluminum alloy, and enhance the surface wettability and surface polarity, which is beneficent to enhance the bonding of the modified polyurethane coating to aluminum alloy surface. The EIS results showed that no any corrosion occurred for the modified polyurethane coating on the treated aluminum alloy during 65 d immersion in 3.5wt.% NaCl solution. The impedance value in low frequency range of the modified polyurethane coating always maintained at a high order of magnitude on the aluminum alloy treated by anodic oxidation and MCA composite film modification, showing an excellent protective performance of the coating system. The evaluation of Neutral Salt Spray (NSS) indicated that the modified polyurethane coating on the treated aluminum alloy owned superior corrosion protection performance, and the adhesion strength remained 13.1 MPa and no any corrosion was found at the scratch locations even after 1200 h of salt spray testing. It was concluded that combination of anodic oxidation and MCA composite film were capable of significantly improving the adhesion of modified polyurethane coating on aluminum alloy and providing long-term effective corrosion protection for aluminum alloy. © 2021 Authors. All rights reserved.     

脉冲复合镀涂层的制备及其高温氧化动力学

水基体系内采用脉冲复合电镀法将镍包铝粉镀到普通碳钢（A3）表面,并与直流电镀结果进行了比较。 结果显示,脉冲复合镀镀层晶粒大小均匀,结合紧密,晶相稳定,镀覆完整,经过热处理,镀层与基体金属之间相互渗透并形成金属间化合物,与钢基体结合牢固,热重分析实验显示此脉冲复合镀镀层经过热处理后显著提高了基体的高温抗氧化性。     

Synthesis and characterization of phosphorized polyaniline doped with phytic acid and its anticorrosion properties for Mg-Li alloy

A phosphorized polyaniline (PANI) doped with phytic acid (PhA) was synthesized by the chemical oxide method with PhA as a dopant and applied to improve the anticorrosion properties of magnesium-lithium (Mg-Li) alloys after blending with eco-friendly silane sol. The chemical structures and morphologies of PANI samples were evaluated by FTIR spectroscopy, UV-Vis-NIR spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). All characterizations indicate that the as-synthesized phosphorized PANI (PANI-PhA) exists in doped emeraldine salt state with net-like structures crosslinked by phosphate carboxyl groups. The conductivity and thermostability of PANI-PhA were better than those of PANI doped with phosphoric acid (PANI-H₃PO₄) and undoped PANI. The anticorrosion properties of PANI/silane sol composite coatings for Mg-Li alloy were tested by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results prove that the anticorrosion ability of PANI-PhA is the best among the three PANI samples, as shown by a low corrosion current (1.28 × 10^?7 A·cm^?2) and high impedance (5.62 × 10⁶ Ω·cm²). The possible anticorrosion mechanism was proposed based on procedure analysis.     

Ni-Cu-P合金镀层在燃气冷凝换热器上的应用

研究硫酸铜镀液中浓度对Ni-Cu-P合金镀层的成分、组织结构及耐腐蚀性能的影响.EPMA、XRD和极化曲线镀层测试表明,以浓度为0.5g.L-1的硫酸铜作镀液镀层的耐蚀性能最优.在天然气冷凝液中考察了Ni-Cu-P、Ni-P合金镀层和铜基体的电化学耐腐蚀性能,Ni-Cu-P合金镀层的自腐蚀电位低,自腐蚀电流密度小,交流阻抗值最大.因此该镀层可作为铜质燃气冷凝换热器的耐蚀阻挡层和牺牲阳极保护镀层,防止铜管腐蚀穿孔,有效地延长铜质冷凝换热器的使用寿命.     

Bandgap modification of TiO<Subscript>2</Subscript> sol–gel films by Fe and Ni doping

Nickle and iron doped TiO₂ thin films were prepared on glass substrates by sol–gel dip coating process. Indirect and direct optical energy gaps were calculated with the incorporation of different concentrations of both the ions. Indirect bandgap was found to be a strong function of the dopant concentration, whereas direct energy gap has negligible dependence on the nature of dopant and its concentration. Direct energy gap has always been found to retain a value higher than the indirect energy gap. Variation of observed energy gap properties shows a trend similar to that reported on the basis of numerical calculations or the samples obtained by other techniques. Increase in refractive index and corresponding density of the film sample does not support the change in turn over frequency. The influence of crystalline phase change is also ruled out by XRD investigations. It is concluded that red shift of band edge absorption takes place by incorporation of dopant and sol–gel dip coating technique offers an effective low cost route to the production of these coatings.     

Surface characterization of growth process for cerium conversion coating on magnesium alloy and its anticorrosion mechanism

Cerium conversion coating is successfully deposited on magnesium alloy AZ31 for corrosion protection. Deposition time on the influence of cerium conversion coating morphology, composition, and electrochemical properties has been investigated in detail. Morphological observation reveals that the cerium conversion coating is a porous agglomerate nanostructure. XPS indicates that the coating exhibits a time‐dependent ingredient. Moreover, the coating is considered as a combination of magnesium oxide/hydroxide and cerium (III) and (IV) oxides/hydroxides. The results of electrochemical impedance spectroscopy indicate that the anticorrosion coating exhibits the best properties during deposition of 5 min. In view of the analysis, the anticorrosion mechanism is pioneered proposed because of the formation of H‐bonding layer, which forms a reasonable barrier to Cl^? ions. Copyright © 2014 John Wiley & Sons, Ltd.     

电解铜箔表面电沉积Zn-Ni-P-La合金工艺

为了缓解我国高性能铜箔依靠进口的局面,进行了将类金属(P)和稀土金属(La)引入电解铜箔锌镍合金镀层中以获得高耐腐蚀性铜箔的实验。 利用电子能谱(XPS)、X射线衍射(XRD)、扫描电子显微镜(SEM)等技术手段分析镀层质量。 在最佳工艺下获得非晶态Zn-Ni-P-La合金镀层,镀层表面平整均匀、结晶致密,未钝化的情况下,铜箔镀件在180 ℃烘箱中保持1 h不变色,表现出较理想的抗氧化和抗腐蚀能力。 表明镀层中适量的P和稀土La对改善镀层质量有着重要的作用,具有较好的工业应用前景。     

紫外光-热双固化聚苯胺防腐涂料

以酸性磷酸酯为掺杂剂对本征态聚苯胺(EB)进行掺杂,制备了可在聚氨酯和聚氨酯丙烯酸酯中进行纳米分散的导电聚苯胺(ES),其粒径分布在80~750 nm之间可控。 在此基础上,制备了不含重金属的紫外光-热双固化聚苯胺防腐涂料。 该防腐涂料先后经过3~5 s紫外光固化和80 ℃下1~3 min的热固化,即可完成紫外光-热双固化过程。 由于ES与聚氨酯或聚氨酯丙烯酸酯之间是不相容体系,因此随着ES质量分数的增大,会导致ES的团聚,分散粒径增大。 当ES质量分数从1.0%增大到5.0%时,ES的粒径从80~119 nm增加到500~750 nm。 ES的分散粒径增大会导致防腐涂层的致密性变差,降低防腐效果。 与普通紫外光固化聚苯胺防腐涂层相比,当ES为1.0%时,紫外光-热双固化防腐涂层在质量分数为3.5%的NaCl水溶液中浸泡2160 h后,其0.1 Hz下的绝对阻抗值(|Z|_{0.1 Hz})仍高于1.0×10⁸ Ω·cm²,优于普通紫外光固化聚苯胺防腐涂层的|Z|_{0.1 Hz}(1.0×10⁷ Ω·cm²),表明紫外光-热双固化涂层的防腐效果有了显著改善。 经过500 h划叉中性盐雾试验后,普通紫外光固化防腐涂层的板面出现了锈蚀宽度小于1 mm的锈蚀,而紫外光-热双固化防腐涂层经过500 h划叉中性盐雾试验,板面没有出现生锈、起泡的现象,表明紫外光-热双固化路线对提高涂层的防腐性能具有较大的价值。     

Effect of AA2024‐T3 surface pretreatment on the physicochemical properties and the anticorrosion performance of poly(γ‐glycidoxypropyltrimethoxysilane) sol‐gel coating

This study investigated the dependence of the anticorrosion performance of a poly(γ‐glycidoxypropyltrimethoxysilane) (poly(γ‐GPTMS)) sol‐gel coating on AA2024‐T3 aluminum alloy surface state. Two different AA2024‐T3 surface pretreatment procedures were tested: a degreasing with acetone and a chemical multistep etching process (industrial chemical etching pretreatment). Poly(γ‐GPTMS) coatings were deposited onto both pretreated surfaces using the dip‐coating technique. Surfaces were characterized principally by scanning electron microscopy, X‐ray photoelectron spectroscopy, Fourier transform infrared attenuated total reflectance, contact angles, and roughness measurements. Moreover, for the coated AA2024‐T3 surfaces, a pull‐off test was used to evaluate the poly(γ‐GPTMS) adhesion to the pretreated surface. Bare surface properties depended on the applied pretreatment. The chemically etched surface was the roughest and the most concentrated in hydroxyl groups. In addition, comparatively to the degreased surface, it has a more hydrophobic character. Poly(γ‐GPTMS) coating revealed an uneven nature and a poor adhesion once it was deposited onto the degreased surface. Coatings anticorrosion performances were evaluated using electrochemical impedance spectroscopy measurements (EIS). Electrochemical impedance spectroscopy data proved that the sol‐gel coating applied onto the chemically etched surface had better anticorrosion performance.     

Composite film coatings based on epoxy-polysiloxane systems of cationic polymerization and their anticorrosion properties

The anticorrosion properties of epoxy-polysiloxane coatings on the surface of the aluminum alloy D-16 were studied by a potentiodynamic method. It was established that the use of the hybrid coating led to an increased corrosion resistance from 0.250 kΩm·cm² for uncoated alloy to 0.396-0.996 kΩm·cm² for the coated aluminum support. The yield of the sol fraction, the micro hardness, and the glass transition temperature of the polymers were determined.     

镁合金化学转化膜的制备及其性能研究

在磷酸钠-磷酸二氢铵-高锰酸钾体系中对镁合金进行化学转化处理.研究了磷酸钠、磷酸二氢铵、高锰酸钾、温度、时间和添加剂对转化膜性能的影响.通过对转化膜结构、成分及性能的测试评价,得到了性能较好的化学转化溶液配方:Na3PO4为5g·L-1,NH4H2PO4为15 g· L-1,KMnO4为1g· L-1,添加剂(NH4)6 Mo7O24为0.5g·L-1.由SEM可观察到转化膜的表面成“干枯河床”状.XRD和EDS检测表明,膜层的主要成分是Mg,Al12 Mg17和无定形相,膜层表面主要有Mn,Mg,K,O和Al等元素组成.腐蚀实验和电化学测试表明,添加剂能够降低转化膜的腐蚀率,转化膜较基体的腐蚀电位正移了0.73 V,提高了镁合金的耐蚀性.     

Features of formation of magnetite coatings on low-carbon steel in hot nitrate solutions

The process of anticorrosion magnetite coating (MC) formation on low-carbon steel is studied in alkali-free nitrate converting media at the temperatures of 70–98°C reduced as compared to those used (130–145°C) in standard technologies of steel bluing: formation of such coatings in alkaline nitrate solutions. Alongside with the conventional corrosion-electrochemical methods of analysis of the formed MCs, the regularities of the MC surface reliefs were studied using the method of atomic force microscopy combined with the technique of flicker-noise spectroscopy (FNS) for processing digitized images and obtaining the parameters of the MC surface structure in different nanometer ranges. It was shown that it is necessary to introduce additives of metal nitrates with a low cation radius into the ammonium nitrate converting solution to obtain MCs with a high corrosion stability at the first stage of MC formation and the final stage must consist in the further “passivation” of MCs: MC treatment by aqueous solutions based on nontoxic carboxylates. According to the FNS analysis of the surface structure of the formed MCs, a significant decrease of the FNS “point” factor, an indicator of MC corrosion instability, occurred during the final treatment. On this basis, one could characterize quantitatively the results of accelerated corrosion tests: no steel corrosion occurred on the thus formed coatings for 42 days under standard severe conditions: 100% relative humidity and daily “showering”. The performed study reveals fundamental possibilities for solving the problems of standardization of the anticorrosion coating surface based on the analysis of their surface profile in the nanometer range.