镀锡薄钢板在功能饮料中的腐蚀行为

应用电化学阻抗谱(EIS)技术,结合扫描电镜(SEM)、能量散射X射线谱(EDS)、X射线光电子能谱(XPS)、扫描探针显微镜(SPM)等表面分析技术,研究了镀锡薄钢板在功能饮料中的腐蚀过程并探讨了腐蚀机制.结果表明:浸泡前期,EIS低频阻抗模值的增加与前31 h镀锡薄钢板表面形成的腐蚀产物膜有关;随着浸泡时间的增加,EIS低频阻抗模值有所下降,这与腐蚀产物膜的部分脱落以及暴露的基底金属碳钢的腐蚀有关.镀锡薄钢板在功能饮料中浸泡24天后其表面的腐蚀产物膜由外层的富锡层和内层的富铁层组成,XPS结果表明其成分主要是Sn(Ⅱ)/Sn(Ⅳ)与柠檬酸阴离子及Fe(Ⅲ)与柠檬酸阴离子组成的化合物,其腐蚀类型主要是功能饮料中的有机酸对镀锡薄钢板的腐蚀.     

Effect of the feeding mode of cross-linker and microcapsule on the corrosion resistance and hydrophobicity of composite coatings

The interface combination of anti-corrosive materials and polymer matrix has a significant effect on the overall performance of the composite coating. However, past research has focused on blending anti-corrosive materials to improve the performance of the polymer matrix. Herein, we proposed a layer-by-layer spray-coating process to further enhance the reinforcing effect of anti-corrosive materials on the polymer matrix by changing their feeding modes. In this paper, taking waterborne polyacrylate (WPA) as an example, two kinds of reinforcement materials commonly used to improve the corrosion resistance of polymer matrix were introduced into the coating system and then applied to the tinplate: cross-linker and microcapsule. Firstly, five types of WPA composite coating systems were designed according to the feeding mode of aziridine cross-linker and the position of benzotriazole@zinc oxide microcapsules (BTA@ZnO MCs). Electrochemical impedance spectroscopy (EIS) and electrical equivalent circuits were used to evaluate the corrosion resistance of these composite coating systems and analyze their electrochemical processes. By spraying the mixture of WPA and aziridine crosslinker as the bottom layer and BTA@ZnO MCs as the top layer, the resulting composite coating exhibited higher corrosion resistance and hydrophobic properties. Scanning electron microscope (SEM) and contact angle tests indicated that the feeding mode of aziridine cross-linker and the position of BTA@ZnO MCs played important roles in the compactness and hydrophobicity of the composite coating. Subsequently, the effects of the amount of aziridine cross-linker and BTA@ZnO MCs on the corrosion resistance and physical properties of the composite coating were further analyzed by EIS, water absorption test, contact angle test and atomic force microscopy (AFM). The significant improvement in the corrosion resistance of this composite coating was mainly attributed to the synergistic effect of highly cross-linked network structure and superhydrophobic surface.     

Determination of total tin in canned food using inductively coupled plasma atomic emission spectroscopy

Tin is considered to be a priority contaminant by the Codex Alimentarius Commission. Tin can enter foods either from natural sources, environmental pollution, packaging material or pesticides. Higher concentrations are found in processed food and canned foods. Dissolution of the tinplate depends on the of food matrix, acidity, presence of oxidising reagents (anthocyanin, nitrate, iron and copper) presence of air (oxygen) in the headspace, time and storage temperature. To reduce corrosion and dissolution of tin, nowadays cans are usually lacquered, which gives a marked reduction of tin migration into the food product. Due to the lack of modern validated published methods for food products, an ICP-AES (Inductively coupled plasma-atomic emission spectroscopy) method has been developed and evaluated. This technique is available in many laboratories in the food industry and is more sensitive than atomic absorption. Conditions of sample preparation and spectroscopic parameters for tin measurement by axial ICP-AES were investigated for their ruggedness. Two methods of preparation involving high-pressure ashing or microwave digestion in volumetric flasks were evaluated. They gave complete recovery of tin with similar accuracy and precision. Recoveries of tin from spiked products with two levels of tin were in the range 99+/-5%. Robust relative repeatabilities and intermediate reproducibilities were <5% for different food matrices containing >30 mg/kg of tin. Internal standard correction (indium or strontium) did not improve the method performance. Three emission lines for tin were tested (189.927, 283.998 and 235.485 nm) but only 189.927 nm was found to be robust enough with respect to interferences, especially at low tin concentrations. The LOQ (limit of quantification) was around 0.8 mg/kg at 189.927 nm. A survey of tin content in a range of canned foods is given.     

Corrosion resistance of amorphous AlPO4 coating in salty atmospheres

The objective of the present study was to introduce a cost-effective and environmentally friendly coating to improve the corrosion resistance of the structures located in salt water. The coating solution, based on amorphous aluminum phosphate composition, was synthesized by sol–gel process and applied to AISI 304 stainless steel by dip coating technique. X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy analyses were employed to investigate the phase composition and morphology of the coating. Corrosion behavior of the uncoated and coated samples was investigated using standard salt spray test, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. Salt spray test results for the bare substrate revealed a corrosion rate of six-time greater than that of the coated surface after 168 hr exposure time. Electrochemical test results declared that the amorphous AlPO₄ coating decreased the corrosion current density of the AISI 304 stainless steel by 10 orders of magnitude. Furthermore, according to the corresponding EIS measurements, the coated surface exhibited a superior anti-corrosion performance than uncoated sample. Overall, the results declared that the amorphous AlPO₄ coating could be a good choice for surface protection of stainless steel against electrochemical corrosion in salty environments.     

Alloying during codeposition of copper and tin out of silicofluoride electrolytes

A technique for obtaining binary Cu-Sn alloys containing 20–35 mol % Sn is proposed. The technique—the electrochemical deposition out of silicofluoride electrolytes—ensures a high deposition rate of coatings (25–50 μm h^?1). The formation of intermetallic compound Cu₁₀Sn₃ is found to occur at a high current density, in conditions of the tin reduction depolarization and the copper reduction superpolarization. The alloys consist of submicron grains. Apart from crystalline Cu₁₀Sn₃, they include x-ray-amorphous tin (2–12 mol %) and tin oxides (≤1–3 mol %). The alloys feature high hardness (4200 MPa), corrosion resistance, and solderability.     

XPS和AES研究锡表面的防变色膜

通过比较多种防锡变色剂的防变色效果,发现乙二胺四甲叉膦酸(EDTMP)是一种优良的防锡变色剂。用XPS、AES及Raman光谱探讨了EDTMP的防变色机理,结果表明EDTMP在锡表面形成了一种耐蚀性保护膜。在深度剖析曲线的元素组成近似恒定区测得膜的相对原子浓度(A.C.％)为:O 48.0％;Sn 10.7％;N 7.7％;C 23.1％;P 10.5％。     

In situ study the dependence of electrochemical migration of tin on chloride

The dependence of electrochemical migration (ECM) of tin on chloride was investigated using in situ electrochemical and optical techniques. An interesting phenomenon is first found that tin dendrite grows not only in the electrolyte layer with low chloride concentration but also in the electrolyte layer with high chloride concentration, although it is generally suggested that the growth of tin dendrite through ECM is not available in solution with high chloride concentration. Mechanisms have been proposed to explain the ECM of tin in the electrolyte layer with various chloride concentrations.     

镀锡层上钛-磷复合体系钝化膜的制备与表征

通过钛盐与磷酸盐体系复配的方法,在镀锡层表面得到了一种钛-磷复合体系钝化膜. 利用扫描电子显微镜(SEM)、X射线光电子能谱 (XPS)、盐雾试验、Tafel极化曲线和EIS交流阻抗谱测试等方法,研究了所得钝化膜的表面形貌、组成与耐蚀性能. 结果表明,得到的钝化膜层的主要组成成分为Ti₃(PO₄)₄nH₂O和TiO₂,在镀锡层表面结晶细致并有封孔的作用,因此有很好的耐蚀性能.     

Tin corrosion in highly acidic solutions containing ethylene glycol oligomers and halides: An electrochemical quartz crystal microbalance study

Tin corrosion in 1 M H₂SO₄ solutions containing 0.01 M Sn(II), 0.01 M ethylene glycol or its oligomers, and 30 μM of various halides is studied by the electrochemical quartz crystal microbalance method. The current density of the tin electrode corrosion is found to approach a few tens of μA cm^?2. In the presence of Sn(II), the current density is nearly half that in its absence. The corrosion potential steadily increases with time, approaching a certain limit. In solutions containing Sn(II), the limit practically corresponds to the equilibrium potential of the Sn/Sn²⁺ electrode. The corrosion rate barely depends on the oligomer nature even up to tetraethylene glycol. Halides accelerate the corrosion process. Their action intensifies at initial time instants (up to 15–20 min) in the series Cl^? < Br^? < I^?. The corrosion impedance equals ～1000 ohm cm². It may be ignored when analyzing the overall impedance of the tin electrode in the frequency region extending from 0.1 Hz to 50 kHz.     

Investigation of hydrogen embrittlement of Sn–Al alloy during contact with water vapour

The humid air induced processes of embrittlement of the Sn–Al alloy and hydrogen emission have been investigated. Using the secondary-ion mass spectrometry, X-ray, scanning electron microscopy and energy-dispersive X-ray spectrometry techniques it was found that the brittleness is caused by a failure of phase adhesion due to accumulation of hydrogen and formation of oxidized layers on phase boundaries during contact of the alloy with water vapour. Specific physical and electrochemical properties of the Sn/Al phase boundary satisfy conditions for the formation of atomic hydrogen and its reaction with Sn. Electrochemical corrosion plays an important role at the stage of formation of atomic hydrogen. The penetration of hydrogen and its accumulation in the bulk of the alloy is due to the high energy of the phase boundary and the low energy of formation of unstable tin hydride. Electronic Publication     

电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量

建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量的方法。为避免复杂基体、溶样时间对测试结果产生干扰,采用标准加入法进行定量分析。通过实验,确定了溶样用盐酸的浓度、ICP仪器参数以及待测元素的分析线。考察了标准曲线的相关性、精密度和准确度等分析指标。结果表明,标准曲线成线性关系(R=0.998 8),检测结果的相对标准偏差仅为1.3%,与现有的国家标准分析方法——碘酸钾滴定法和X射线荧光光谱法进行对比实验,测量结果基本一致。     

Facile electrochemical route to directly fabricate hierarchical spherical cupreous microstructures: Toward superhydrophobic surface

A templateless, surfactantless, electrochemical route is proposed to directly fabricate hierarchical spherical cupreous microstructures (HSCMs) on an indium tin oxide (ITO) substrate. The as-prepared HSCMs have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The HSCMs prepared by simple potentiostatic technique exhibit hierarchical spherical microstructures with higher roughness. After further chemisorption of a self-assembled monolayer of n-dodecanethiol, the as-prepared compact surface becomes superhydrophobic with a contact angle as high as 152°.     

Electrochemical corrosion kinetics of tin and tin amalgams in NaCl aqueous solutions

Electrochemical techniques were used to determine the corrosion rate of pure tin metal as compared to 80 Sn/20 Hg tin amalgam. X-ray diagrams showed that this amalgam was a crystalline γ₂ phase, whereas a 50 Sn/50 Hg amalgam contained liquid alloy embedded in the same γ₂ phase. Open circuit potential measurements, combined with narrow range potential scanning voltammetry, lead to the conclusion that amalgamation resulted in enhancement of the corrosion current, mainly by increasing the cathodic electron transfer reaction kinetics both in deaerated and in oxygen-saturated NaCl solution. When maintained at zero current potential in a solution containing dissolved O₂ gas, the samples were gradually covered with an insulating oxide layer which was identified by a series of electrochemical impedance diagrams recorded at different time intervals. The oxide layer was firmly adherent to the bulk tin metal but was poor at protecting the amalgam electrode. Finally, at potential values where the anodic current reached a few mA/cm², the pure tin metal surface was suddenly deteriorated by the formation of extremely deep pinhole corrosion pits, while this effect was smoothed down by amalgamation. Electronic Publication     

Corrosion resistance and durability of superhydrophobic surface formed on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution

The corrosion resistant performance and durability of the superhydrophobic surface on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution were investigated using electrochemical and contact angle measurements. The durability of the superhydrophobic surface in corrosive 5 wt% NaCl aqueous solution was elucidated. The corrosion resistant performance of the superhydrophobic surface formed on magnesium alloy was estimated by electrochemical impedance spectroscopy (EIS) measurements. The EIS measurements and appropriate equivalent circuit models revealed that the superhydrophobic surface considerably improved the corrosion resistant performance of magnesium alloy AZ31. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test was performed to investigate the adhesion of the superhydrophobic film to the magnesium alloy surface. The corrosion formation mechanism of the superhydrophobic surface formed on the magnesium alloy was also proposed.     

分散液膜气/液/固三相线界面区宽度在金属大气腐蚀中的作用(英文)

使用接触角测量和电化学技术研究了三相线界面区(TPB)宽度在分散液膜下金属腐蚀过程中的作用.研究发现,阴极极限电流和腐蚀电流密度随TPB宽度增加而线性增大,表明TPB宽度对气/液/固多相体系腐蚀过程具有重要影响.因此,可根据TPB宽度评价分散液膜厚度对大气腐蚀速率之影响.     

Application of laser micro- and nanotexturing for the fabrication of superhydrophobic corrosion-resistant coatings on aluminum

A new efficient method for the fabrication of corrosion-resistant composite superhydrophobic coatings on aluminum and its alloys is presented. The laser micro- and nanotexturing of the surface combined with the deposition of a hydrophobic agent makes it possible to obtain superhydrophobic coatings with unique properties on aluminum materials. The complex studies by electrochemical methods and wettability analysis showed that the proposed type of coatings is characterized by very high resistance to corrosion, including pitting resistance, and by the durability of the superhydrophobic state upon prolonged contact with aqueous chloride-containing media.     

金属缓蚀剂Gemini型咪唑啉双季铵盐的合成及其性能的研究

合成了系列新型咪唑啉双季铵盐阳离子缓蚀剂（S-HSJ）,研究并讨论了其在5%盐酸介质中对铜、铝等金属的缓蚀性能及缓蚀剂结构中亲油基部分碳链长度、缓蚀时间、缓蚀剂浓度等对缓蚀效果的影响。研究表明：S-HSJ系列咪唑啉双季铵盐对红铜、黄铜、铝及马口铁四种金属均表现出较传统单季铵盐与苯并三氮唑缓蚀剂好的缓蚀性能,S-HSJ-16双季铵盐添加量0.1%时缓蚀效率可达94~99%,S-HSJ与阴离子表面活性剂复配对铜腐蚀表现出明显协同效应。     

Characterization of chromate conversion film on tinplate substrate by XPS and electrochemistry methods

The chromate conversion coating formed on commercial tinplate via a cathode electrolytic dichromate treatment has been studied by X‐ray photoelectron spectroscopy (XPS) and electrochemistry methods. Through the analysis of the XPS, it was shown that there existed Cr, O, and Sn in the chromate coating and the chromate film consisted mainly of Cr(OH)₃, Cr₂O₃, Sn, and SnO_x. The current density decreased with increasing of the electric charge. The corrosion resistance for tinplate is relative with the content of chromium in the passivation film. Copyright © 2009 John Wiley & Sons, Ltd.     

AZ31和AZ61镁合金在模拟海水中的腐蚀电化学行为

应用极化曲线、电化学阻抗谱方法研究了两种Mg-Al-Zn系合金——AZ31和AZ61在模拟海水中的腐蚀电化学行为.根据两种镁合金在浸泡过程中腐蚀介质pH值的变化以及扫描电子显微镜对合金微观金相组织和腐蚀形貌的观察,讨论了镁合金的腐蚀机理及合金元素Al的含量对镁合金耐蚀性能的影响.结果表明,AZ61镁合金具有比AZ31镁合金更好的耐蚀性能,其原因主要是AZ61镁合金中Al含量较高使合金的微观组织结构更有利于耐蚀性能的提高.