EIS法研究3种配套涂层体系的腐蚀电化学行为

采用电化学阻抗谱(EIS)研究了由水性无机富锌底漆、环氧中间漆和氯化橡胶面漆3种涂料配套而成的3种不同涂层体系在3.5%NaCl溶液中的电化学腐蚀行为,考察了氯化橡胶面漆、水性无机富锌底漆／氯化橡胶面漆、水性无机富锌底漆／环氧中间漆／氯化橡胶面漆这3种涂层体系的阻抗谱在浸泡过程中的演化并据此比较了3种涂层体系的防护性能。结果表明,两涂层体系的防护性能比单涂层的还要差,三复合涂层体系的防护性能最好。根据涂层腐蚀电化学阻抗谱特征推测,中间漆在三复合涂层体系中起到了使底漆和面漆结合更加紧密的桥梁作用。     

环氧/氟碳复合涂层对碳钢在盐水中的保护作用研究

用电化学交流阻抗技术(EIS)分析了环氧富锌底漆、环氧云铁中间漆和氟碳面漆配套而成的3种不同涂层体系(单涂层、双涂层及三涂层体系)在3.5%NaCl水溶液中的失效过程。通过|Z|0.01 Hz、涂层孔隙率和吸水率的变化分析了底漆、中间漆和面漆对涂层整体防腐性能的影响。结果表明,环氧云铁中间漆的抗腐蚀介质渗透能力优于环氧富锌底漆和氟碳面漆,对复合涂层体系的防护性能起到了重要作用。浸泡初期,中间漆对涂层屏蔽性能影响很大;浸泡中后期,环氧富锌底漆发挥阴极保护和腐蚀产物的屏蔽作用,使得涂层的防护性能得到有效提高。氟碳/环氧云铁/环氧富锌复合的三涂层体系的吸水率和孔隙率总体最低,吸水率能在较长时间保持在较低水平,对水和离子渗透起到了很有效的屏蔽作用。     

修补保护钢筋混凝土管道支架用防腐涂料的筛选

针对适合混凝土外用的各防腐涂料特点,结合具体的工程应用,通过耐热盐水试验、浸烘试验、碳化试验、现场老化试验和握裹力测试等方法对各种涂料的性能进行评价.结果表明:FH-1环氧呋喃封闭底漆和氯化橡胶面漆配套使用可以作为扬子石化储运厂钢筋混凝土管道支架的外用防腐涂料,性价比最好,修补时对于已生锈的裸露钢筋表面涂刷锈转化剂或环氧富锌底漆与氯化橡胶面漆涂层体系,既可以提高钢筋与混凝土的握裹力,又可以保护钢筋不被腐蚀.     

湛江地区石油储罐防腐配套漆的研究

对冷涂锌底漆、无机富锌底漆、环氧富锌底漆进行2 000 h的耐中性盐雾试验,结果表明:冷涂锌底漆和无机富锌底漆耐盐雾效果最佳,环氧富锌底漆次之;对脂肪族聚氨酯面漆、氟碳面漆、聚硅氧烷面漆进行耐人工气候老化试验,结果表明:氟碳面漆耐人工气候老化效果最好,脂肪族聚氨酯面漆次之,聚硅氧烷面漆较差。从经济性方面考虑,建议配套体系为"无机富锌+环氧封闭漆+环氧云铁漆+脂肪族聚氨酯面漆+氟碳面漆",这种配套体系相对以前的配套体系,成本增加约7元/m~2,但是防腐寿命至少增加5 a以上。     

海运集装箱配套涂料的研制

参照国外集装箱涂料配套方案，确立了自行研制集装箱涂料的主要技术路线，即环氧类与氯化橡胶类底漆和氯化橡胶类面漆配套。测试了自行研制的集装箱涂料底漆、面漆、配套涂层以及改进的氯化橡胶面漆的性能。并将确定的优化配套涂料与获得Ｋｏｎｓｔａｎｄｔ认可的国外同类涂料进行性能对比，结果表明，自制的集装箱涂料综合性能达到了国际同类产品的先进水平。     

水性重防腐涂料在桥梁钢结构上的应用研究

制备了水性环氧富锌底漆、水性环氧云铁中间漆、水性丙烯酸聚氨酯面漆作为配套涂装体系应用在钢箱梁上。实验结果表明,该配套体系具有很好的耐盐雾及施工性能,完全能够替代油性环氧富锌底漆、环氧云铁中间漆、丙烯酸聚氨酯面漆配套体系,并且环保,符合国家节能减排相关政策。     

快干型水性环氧富锌底漆的研制

富锌底漆作为长效型钢结构重防腐涂料涂装配套体系的底漆与其他品种底漆相比,具有防腐性能强、耐热性优良、附着力好等优点。其按成膜物质不同可分为无机、有机、有机／无机掺合3类。有机富锌涂料常用环氧、氯化橡胶、乙烯基树脂和聚氨酯树脂为成膜基料,最为常用的是环氧富锌涂料。其中,聚酰胺固化环氧富锌底漆最常用。该类涂料的特点是长效防腐、表干时间快,     

炼化钢结构水性环保耐候防腐蚀涂料体系研究

开展水性环氧富锌底漆、水性环氧云铁中间漆、水性丙烯酸聚氨酯面漆技术研究,以反应性环氧树脂乳化剂接枝中高分子质量环氧乳液作为环氧体系成膜树脂,提高涂层玻璃化转变温度T_g与防腐蚀性能;以改性水性丙烯酸分散体树脂及100%固含亲水型脂肪族异氰酸酯固化剂作为丙烯酸聚氨酯面漆成膜树脂,实现优异抗光老化;通过耐化学介质与防腐蚀性能等技术方案,形成适用于炼化钢结构等领域C4—CX大气腐蚀环境的水性环保耐候防腐蚀涂料体系,满足相应技术标准要求,安全、环保、性能优异。     

适用于酸雨地区的防腐涂层配套体系性能研究

为选出适用于酸雨地区的涂层体系,通过交流阻抗谱、人工耐老化试验、耐酸雾试验等评价了环氧底漆/丙烯酸改性聚酯面漆、环氧底漆/氟硅丙烯酸面漆、环氧底漆/聚氨酯面漆、环氧底漆/聚硅氧烷面漆和环氧底漆/氟硅面漆这5种涂料配套体系的耐蚀性、耐人工老化性和耐酸雾性,并用扫描电镜观察了涂层在模拟酸雨溶液中浸泡120 d后的表面形貌。结果表明,环氧底漆/硅氧烷面漆体系具有良好的耐人工气候老化和耐酸雾性,孔隙率小,附着力好,可为酸雨地区的输变电铁塔提供较好的防护。     

装配式钢结构水性重防腐涂层的研制

针对我国近海内陆装配式钢结构长效防腐需求,研制了与之配套的水性重防腐涂层。通过调整涂料关键材料的组成及配比,研究了其对水性环氧富锌底漆、水性环氧云铁中间漆以及水性脂肪族丙烯酸聚氨酯面漆关键性能的影响。结果表明：适量的纳米锌粉、云母氧化铁以及离子吸收剂的加入有利于提高底漆的耐腐蚀性和早期耐水性;云母氧化铁与复合磷酸锌颜料合理搭配,有助于提升中间漆的防腐性能;附着力促进剂对水性聚氨酯面漆性能提升显著。所研制的水性环氧富锌底漆、水性环氧云铁中间漆、水性脂肪族丙烯酸聚氨酯面漆及配套涂层的相关性能超过行业标准（HG/T 5176—2017）的性能指标,表明了该涂层体系可以满足 C4环境下的长效防腐要求（ >25 a）,为近海内陆装配式钢结构的表面涂装提供了技术参考。     

不同表面处理条件下复合涂层体系失效过程的EIS特征

研究了不同表面处理条件下环氧富锌/环氧云母氧化铁/氯化橡胶涂层体系的电化学阻抗谱特征。利用Bode图、涂层吸水率、涂层电阻及特征频率的变化评价了表面处理对涂层防护性能的影响。结果表明,基材表面状态不同的复合涂层体系吸水率相对稳定阶段所持续的时间长短顺序为：手工打磨>表面锈蚀>表面未处理,与涂层的防护寿命长短、涂层/基材间的黏附力大小顺序一致。此外,不论基材表面处理程度如何,当涂层体系的特征频率增加到1400 Hz左右时,涂层电阻均发生较快降低,吸水率发生较大增长,涂层失去防护作用。     

Non-substrate EIS monitoring of organic coatings with embedded electrodes

Electrochemical impedance spectroscopy provides a quantitative evaluation of the protection afforded by coatings on metals. Two constraints are that the coating is under immersion and that the substrate acts as the working electrode with the counter and reference electrodes located in the electrolyte. The use of embedded electrodes placed between a topcoat and primer can relax these constraints and make EIS monitoring more applicable to coatings in the field. A two-electrode, non-substrate configuration involves two embedded electrodes on a coated panel acting as the working and counter/reference electrodes. This configuration has been used to characterize the interlayer between a topcoat and primer under the assumption that the current passed through the interlayer. Simulated results have been presented where current passage for a non-substrate configuration was through the metal substrate. The results associated with a urethane topcoat/epoxy primer system and an alkyd topcoat/alkyd primer system are presented to demonstrate the feasibility of monitoring the substrate where the substrate is not an electrode. The degradations of the coatings were induced using the ac–dc–ac accelerated test where the immersed coatings were subjected to cycles that involved a dc cathodic potential condition that promoted the cathodic reactions at the metal/coating interface.     

Study on corrosion electrochemical behavior of several different coating systems by EIS

Corrosion electrochemical behavior of chlorinated rubber top coating (single-layer), inorganic zinc-rich primer/chlorinated rubber top coating (double-layers) and inorganic zinc-rich primer/epoxy middle paste/chlorinated rubber top coating (tri-layers) in 3.5 wt% NaCl solution was studied by electrochemical impedance spectroscopy (EIS). A series of impedance spectra of the three coating systems during immersion were measured; and their protective properties were compared according to the spectra. The experimental results showed that, the protective properties of the double-layers coating system were even worse than that of the single-layer coating system; and the tri-layers coating system had the best protective properties in the three coating systems; epoxy middle paste had played a very important role for protective properties of the composite coating system.     

Effect of UV aging on electrochemical behavior of an anticorrosion paint

The effect of the photochemical artificial ageing (UVA) on the electrochemical behavior of an anticorrosion paint has been studied by electrochemical impedance spectroscopy (EIS). Two types of coatings have been tested: a formulated tri coat system (FS) formed by a primer (epoxy), an intermediate coat (epoxy) and a topcoat (alkyd) which presents a total film thickness of 240 μm and, on the other hand, a non-formulated varnish (NFV) which presents a total film thickness of 70 μm. Panels have been aged in a QUV chamber and the maximal exposure's time was about 1000 h. EIS testing were carried out with a naturally aerated 3% NaCl solution.     

Fire-retardant performance of some surface coatings for naval ship interior applications

The fire-retardant performances of various surface coatings for naval ship interior applications have been evaluated by a number of small-scale fire test methods. The coatings were eveluated as topcoats by cone calorimetry and limiting oxygen index methods and as primer/topcoat systems by radiat heating, direct flame impingement and reverse panel heating procedures. The coatings investigated were (1) a solvent-based epoxy polyester, (2) a solvent-based fireretardant alkyd,(3) a solvent-based chlorimated alkyd and (4) a water-based acrylic. In terms of the measured parameters, the chlorinated alkyd has superior fire properties while the epoxy polyserter, the fire-retardant alkyd and parameters, the chlorinated alkyd has superior fire properties while the epoxy polyester, the fire-retardant alkyd and the acrylic have significat disadvantages in relation to fire propagation. The relatively low amount of hydrogen chloride (～ 0.3%—mass per initial mass) evolved by the chlorinated alkyd during cone calorimetric combustion and its outstanding fire-retardant properties have resulted in it being considered acceptable for naval ship interior applications.     

无机/有机复合涂层体系在3.5%NaCl溶液中的EIS

采用电化学阻抗谱（EIS）研究了无机富锌底漆/环氧云铁中间漆/氯化橡胶面漆复合涂层体系在3.5%NaCl溶液中的腐蚀电化学行为，考察了紫外辐射对其电化学行为的影响。结果表明：复合涂层体系在3.5%NaCl介质中的腐蚀失效过程可以用4种等效电路来等效。浸泡失效前120 h，电解质溶液电阻R_c从开始的5×10⁹ Ω·cm²以大约2.2×10⁷ Ω·h^-1的速度迅速下降到4×10⁵ Ω·cm²，到浸泡120 h后R_c则以较小的速度808 Ω·h^-1下降，涂层电容C_c是按线性增加。紫外辐射不改变复合涂层体系在3.5% NaCl溶液中的电化学行为，仅仅加速复合涂层的失效。     

颜填料体积浓度对水性环氧导静电防腐蚀涂层性能的影响

考察了颜填料体积浓度（PVC）对水性环氧导静电防腐蚀涂料涂层导静电性能和防腐蚀性能的影响,运用X射线能谱（EDX）分析了导电填料的元素组成,采用电化学阻抗谱（EIS）、扫描电镜（SEM）等手段对不同颜填料体积浓度的涂层进行了性能测试及表征,根据不同颜填料体积浓度涂层的物理机械性能、盐水浸泡实验结果和电化学阻抗谱分析,确定该水性环氧导静电防腐蚀涂料的最佳颜填料体积浓度为35%。     

Performance of paint systems with polyurethane topcoats, proposed for atmospheres with very high corrosivity category

The EN ISO Standard 12944-5 describes the types of paint and paint systems commonly used for corrosion protection of steel structures. In this work four paint systems, applied on steel, including polyurethane topcoats, recommended for atmospheres with high corrosivity (C5 category), codified by 1–4, were studied. Systems 1 and 4 include zinc rich primers and epoxy/polyamide intermediates, system 2 has solvent free epoxy/polyamide primer and intermediate and, system 3 is a hybrid system with vinyl–acrylic water based primer and a high solids epoxy/polyamide intermediate. Systems 2–4 have acrylic–polyurethane topcoats and, the topcoat of the system 1 was identified as an aliphatic polyurethane.

According to EN ISO 12944-6, water condensation and neutral salt spray tests were performed. Three exposure times were considered taking into account the durability ranges of paint systems: low, medium and high, respectively. The paint systems were complementary submitted, during 30 days, to ultraviolet radiation with water condensation test according to ASTM G 154. At the same time, natural exposure was conducted in the marine atmosphere of Sines, with very high corrosivity (>C5).

The paint adhesion, before and after artificial ageing, was evaluated by cross-cut test and, for the systems with dry thickness greater than 250 μm, by pull-off test. Visual inspections were carried out.

For the exposure in UV radiation test chamber and at test site, gloss reduction, colour change and chalking were measured. Chemical changes on polyurethane topcoats exposed in the UV radiation test chamber were studied by Fourier transform infrared spectroscopy (FTIR).

In spite of the higher aesthetic degradation by UV radiation, of the aliphatic polyurethane topcoat of the system 1 relatively to the acrylic–polyurethane topcoats of the other systems, system 1 with ethyl silicate zinc rich primer and epoxy intermediate, was the one that presented the best corrosion protection when exposed in artificial and natural salty environments. At the test site, the worst anticorrosive behaviour seems to be presented by the system 2 with two coats of solvent free epoxy paint.     

Environmental studies of smart/self-healing coating system for steel

Smart/self-healing micro-capsulated inhibitor incorporated in epoxy primer before painting on a steel surface was evaluated for its corrosion protection effectiveness on exposure to ASTM D 5894 electrolyte in laboratory and natural tropical sea-shore environment. The “healant” inhibitor was industrial custom-made and non-chromate organic-based microcapsules which were mixed into the primer before applying a polyurethane topcoat layer on steel surface. The results indicate that the active components in ruptured embedded inhibitor microcapsules were released into an inflicted scribe primer and topcoat film on steel surface on exposure to inhibit development of an electrochemical cell. Undamaged surface film of the test and control specimens exposed in the environments demonstrated excellent corrosion-inhibition performance as reflected by both visual inspection and electrochemical impedance spectroscopy experimental data. The results obtained on the performance of self-healing inhibitors should provide an understanding of the fundamental material-property relationships of smart inhibitor coatings. And, thus, should facilitate the development of optimized paint compositions in order to extend the useful service life of steel-infrastructure applications.