热镀锌钢铈盐/硅烷复合膜的制备及其耐蚀性能

热镀锌钢板上单一的铈盐、硅烷钝化膜有一些缺点,对提高其耐蚀性作用不大。为此,将热镀锌钢板先经铈盐溶液处理,再用乙烯基三甲氧基硅烷溶液浸渍,获得了铈盐/硅烷复合钝化膜。采用扫描电镜(SEM)、俄歇电子能谱(AES)、盐水全浸试验和电化学交流阻抗谱(EIS)研究了复合膜层的表面形貌、结构特性和耐蚀性能。结果表明:硅烷膜能较好地填充铈盐转化膜中的裂纹,铈盐/硅烷复合膜层连续、完整、致密,厚400～450 nm,与基体结合较好,复合膜中硅烷膜/铈盐转化膜/锌基体的化学成分呈连续的梯度变化;与热镀锌钢相比,单一铈盐转化膜、硅烷膜的交流阻抗值增加了1个多数量级,复合膜的则增加了约2个数量级,复合膜层的耐蚀性较单一膜层显著增强,且优于常规铬酸盐钝化膜。     

碳钢表面铈盐钝化膜和铈盐-硅烷复合钝化膜的耐蚀性能

碳钢常规铈盐钝化膜的耐蚀性不够理想。以硝酸铈和过氧化氢配制钝化液,通过化学浸泡处理,在Q235碳钢表面制备铈盐钝化膜;通过KH-560硅烷偶联剂对铈盐钝化件进行二次封孔处理,制备了铈盐-硅烷复合钝化膜;对2种钝化膜试样进行了NSS,EIS,SEM和EDS测试。试验结果显示,铈盐钝化膜明显提高了基材的耐蚀性能,但是钝化膜表面存在一些微孔和裂缝,对其耐蚀性能造成不利影响;而硅烷膜能够完整覆盖和填充铈盐钝化膜表面的缝隙和微孔,改善了铈盐钝化膜的耐蚀性能。     

硫代乙酰胺对镀锌钢表面铈盐转化膜耐蚀改性的影响

为了提高镀锌钢表面铈盐转化膜的耐蚀性能,添加硫代乙酰胺对其进行改性,采用扫描电镜(SEM)、能谱(EDS)、中性盐雾(NSS)和极化曲线对铈盐转化膜改性前后的形貌结构、成分和耐蚀性能进行分析测试。结果表明:硫代乙酰胺的加入大大增加了铈盐转化膜的反应时间和膜层厚度以及转化膜有效耐蚀成分O,P,Ce的含量,使得试片耐中性盐雾腐蚀时间由改性前的24 h提高到改性后的288 h,铈盐转化膜的耐蚀性显著提高。     

热镀锌钢表面硅烷/硅酸盐复合膜的耐蚀性能研究

为了改善硅烷膜的耐蚀性,将硅烷化热镀锌钢板用硅酸钠溶液封闭后处理,获得了硅烷/硅酸盐复合膜.采用中性盐雾试验(NSS)、湿热试验、盐水全浸试验和电化学交流阻抗谱(EIS)评价了膜层的耐蚀性能.结果表明,与单一硅烷膜相比,复合膜的耐蚀性能明显提高,超过了常规铬酸盐钝化膜.尤其是在5%NaCl溶液中,复合膜的低频阻抗数值随浸泡时间的增加先增大后减小,表明其具有一定的"自修复"能力.     

硅烷-铈盐复合膜的制备及其耐蚀性能

将自组装膜和稀土转化膜结合可以强化各自的优点,制成的复合膜的耐蚀性能得到极大提高,目前此类研究还不系统。在铜片表面先自组装硅烷膜,再铈盐转化成膜,以复合膜耐蚀性为评价指标,对自组装时间、铈盐转化时间进行优化,对优化条件制成的复合膜的耐蚀性进行研究,与单一的硅烷自组装膜、铈盐转化膜进行比较,并对硅烷-铈盐复合膜的成膜、耐蚀机理进行了探讨。结果表明:硅烷自组装膜与铈盐转化膜的最佳成膜时间分别为10.0 min和1.0 min,硅烷-铈盐复合膜对铜的防腐蚀性能比2种单一膜的有明显提高。     

6061铝合金表面硅烷-镧盐复合转化膜的耐蚀性能和结合力

目前国内对稀土硝酸镧改性硅烷膜的耐蚀性少见研究报道。采用极化曲线、硫酸铜点滴试验方法,研究了硝酸镧对6061铝合金表面γ-氨丙基三甲氧基硅烷(KH-550)硅烷膜耐蚀性能的影响;通过全浸腐蚀试验进一步研究复合膜、空白试样、硅烷膜试样、镧盐钝化膜试样与有机涂层间的结合力。结果表明:在KH-550硅烷基础溶液中添加一定量硝酸镧可有效提高硅烷膜的耐蚀性和结合力;所得复合膜层均匀、致密。同时初步探讨了复合膜的耐蚀机理。     

镁合金表面硅烷转化膜与阳极氧化膜的协同防护性能

目前对镁合金进行硅烷处理后再制备阳极氧化膜的研究未见报道。为此,探讨了镁合金表面硅烷化预处理所制备硅烷转化膜与阳极氧化后处理所制备阳极氧化膜的协同防护性能。在AZ91D镁合金表面首先进行硅烷化预处理制备内层的硅烷转化膜,接着进行阳极氧化后处理再制备外层的阳极氧化膜,最后采用KMnO4点滴试验、NaCl盐水浸泡试验、动电位极化曲线和电化学阻抗谱(EIS)等方法评价并比较了硅烷转化/阳极氧化复合膜、单一硅烷转化膜和单一阳极氧化膜对镁合金基体的防护性能。结果表明:与只经硅烷化处理的镁合金(表面附着单一硅烷转化膜)和只经阳极氧化处理的镁合金(表面附着单一阳极氧化膜)相比,经过硅烷化预处理和阳极氧化后处理的镁合金(表面附着硅烷转化/阳极氧化复合膜)的点滴液变色时间(tdrop)最长、腐蚀速率(vloss)和腐蚀电流密度(Jcorr)最小、自腐蚀电位(Ecorr)最正、膜层电阻(Rc)最大。对镁合金表面先进行硅烷化预处理再进行阳极氧化后处理使得镁合金的耐蚀性得以进一步提高,这主要归因于硅烷转化膜和阳极氧化膜的协同防护对腐蚀历程中扩散过程的抑制。     

镀锌钢板硅烷与稀土铈盐、镧盐复合钝化的性能及机理

试验采用γ-氨丙基三乙氧基硅烷(γ-APS)协同稀土铈盐和镧盐钝化镀锌钢板.通过先在试样表面自组装一层γ-APS薄膜,再沉积稀土转化膜制备硅烷稀土复合膜.采用电化学交流阻抗技术(EIS)、盐雾试验检测复合膜的耐腐蚀性,结果表明复合膜的耐腐蚀性和致密性相对于单一硅烷、稀土转化膜大幅度提高,其中硅烷-铈盐复合膜比硅烷-镧盐复合膜耐腐蚀,中性盐雾试验时间达到76 h.原子力显微镜检测结果表明,复合膜相对于单一稀土转化膜平整.EDS检测结果得出,硅烷与稀土化合物发生了协同作用,促进了稀土转化膜在锌表面沉积.初步探讨了复合膜的成膜机理和耐腐蚀机理.     

硝酸镧掺杂对6061铝合金表面硅烷膜耐蚀性能的影响

为改善铝及铝合金的表面防腐蚀性能,在γ-(2,3-环氧丙氧)丙基三甲氧基硅烷(KH-560)基础溶液中添加不同含量的硝酸镧,在6061铝合金表面制备不同硝酸镧浓度掺杂的硅烷-镧盐复合膜;采用极化曲线、硫酸铜点滴、腐蚀失重率试验等方法分析膜层性能,并得出了镧盐最佳用量。对比分析了最佳镧盐用量下复合膜、硅烷膜和稀土转化膜的耐蚀性能。结果表明:在KH-560硅烷膜制备过程中添加一定量硝酸镧可有效提高硅烷膜的耐蚀性,添加15 g/L硝酸镧时,形成的复合膜层致密且没有裂纹,耐蚀性最好;与单一的硅烷、镧盐转化膜相比,复合膜表现出很好的耐蚀性。     

6061铝合金表面γ-APS协同稀土镧盐复合膜的性能

单一硅烷转化膜对金属基体的保护不足,稀土处理可对硅烷转化膜进行改性。以硅烷γ-APS协同稀土镧盐处理6061铝合金板材,在硅烷基础溶液中添加不同含量的稀土硝酸镧对6061铝合金进行转化处理,采用电化学方法和硫酸铜点滴方法,研究了硝酸镧含量对铝合金基体表面γ-氨丙基三乙氧基硅烷(KH-602)硅烷膜耐蚀性能的影响,通过划格法和模拟大气腐蚀研究复合膜、硅烷膜试样、镧盐钝化膜试样与有机涂层间的结合力。结果表明:在KH-602硅烷基础溶液中添加15 g/L硝酸镧时硅烷镧盐复合膜的耐蚀性和结合力最好;复合膜主要由S,O,Si,Al,La元素组成,其中La元素含量明显高于单一稀土转化膜;与硅烷膜、镧盐转化膜相比,复合膜表现出很好的耐蚀性。     

Corrosion resistance of a silane/ceria modified Mg--Al-layered double hydroxide on AA5005 aluminum alloy

The present work aimed at assessing the electrochemical behavior and the corrosion inhibition performance of Mg--Al-layered double hydroxide (LDH) coatings modified with methyltrimethoxysilane (MTMS) and cerium nitrate on AA5005 aluminum alloy. The chemical compositions and surface morphologies of the coatings were investigated by XRD, FT-IR and FE-SEM, while their corrosion resistance was evaluated by electrochemical and immersion tests. An optimum corrosion resistance of the composite coatings was obtained by adding 10⁻² mol·L⁻¹ cerium nitrate. An excess addition of cerium nitrate resulted in a loose structure and poor corrosion resistance of the coating. The corrosion mechanism of the composite coatings was proposed and discussed.     

黄铜表面复合纳米硅烷膜的制备及其耐蚀性能

目前对黄铜表面处理时采用复合纳米硅烷膜技术的研究报道不多。在黄铜表面采用浸涂技术制备γ-巯丙基三甲氧基硅烷膜,运用电化学方法研究复合纳米硅烷膜在3.50%氯化钠溶液中的耐蚀性,并用SEM表征复合纳米硅烷膜黄铜腐蚀前后的形貌。结果表明:添加纳米材料复合纳米硅烷膜的黄铜在3.50%的氯化钠溶液中具有很强的耐蚀性,其自腐蚀电流密度下降至3.576×10~(-9)A/cm~2,自腐蚀电位正移。添加纳米材料的复合纳米硅烷膜在腐蚀前后的形貌基本不变,耐蚀性明显优于未添加纳米材料的纯硅烷膜。     

Corrosion behaviour of sol–gel coatings doped with cerium salts on 2024-T3 aluminum alloy

The corrosion behaviour of the sol–gel coatings doped with cerium chloride or cerium nitrate on 2024-T3 aluminum alloy was investigated by using electrochemical impedance spectroscopy (EIS) and immersion tests. The sol–gel matrix was obtained through hydrolysis, condensation of 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetramethoxysilane (TMOS), using diethylentriamine as curing agent. The results indicated that cerium nitrate with concentration of 1 × 10⁻³ mol L⁻¹ in the silane solution was excellent on self-healing for the sol–gel coating, while cerium chloride had no obvious effect. This result suggested that the introduction of Cl⁻ promoted the under-film pitting of 2024-T3 substrate. It was found that Ce(OH)₃ and Ce(OH)₂²⁺ simultaneously existed in the silane solution by X-ray diffraction (XRD) analysis. Ce(OH)₂²⁺ transformed to CeO₂ due to high-temperature curing of sol–gel matrix demonstrated by X-ray photoelectron spectroscopy (XPS) analysis. Therefore, it can be considered that Ce(OH)₃ and CeO₂ played inhibition roles in the corrosion process of the sol–gel coatings.     

Morphological and electrochemical characterization of electrodeposited Zn–Ag nanoparticle composite coatings

Silver nanoparticles with an average size of 23 nm were chemically synthesized and used to fabricate Zn–Ag composite coatings. The Zn–Ag composite coatings were generated by electrodeposition method using a simple sulfate plating bath dispersed with 0.5, 1 and 1.5 g/l of Ag nanoparticles. Scanning electron microscopy, X-ray diffraction and texture co-efficient calculations revealed that Ag nanoparticles appreciably influenced the morphology, micro-structure and texture of the deposit. It was also noticed that agglomerates of Ag nanoparticles, in the case of high bath load conditions, produced defects and dislocations on the deposit surface. Ag nanoparticles altered the corrosion resistance property of Zn–Ag composite coatings as observed from Tafel polarization, electrochemical impedance analysis and an immersion test. Reduction in corrosion rate with increased charge transfer resistance was observed for Zn–Ag composite coatings when compared to a pure Zn coating. However, the particle concentration in the plating bath and their agglomeration state directly influenced the surface morphology and the subsequent corrosion behavior of the deposits.     

Effects of ceria nanoparticle concentrations on the morphology and corrosion resistance of cerium–silane hybrid coatings on electro-galvanized steel substrates

This work investigates the effect of the ceria nanoparticle concentration on the morphology and electrochemical behavior of cerium–silane hybrid coatings deposited on electro-galvanized steel substrates. The substrates were pre-treated with 3-glycidoxypropyl-trimethoxysilane and bisphenol A, modified with cerium ion-activated CeO₂ nanoparticles. The morphology of the coating before and after corrosion tests was examined using atomic force microscopy and scanning electron microscopy. The results indicate the formation of nanostructured surfaces with relatively uniform thicknesses and nanoparticle distribution. Microscopic observations explain the increased durability of the silane coating doped with the lowest content of activated ceria nanoparticles after short-term corrosion tests (456 h). The corrosion behavior of the sol–gel coatings was also investigated using natural salt spray tests, electrochemical impedance spectroscopy, and potentiodynamic polarization tests. The results show that the concentration of nanoparticles has a significant impact on the barrier properties of the silane films, which are improved for films with lower nanoparticle contents.     

LY12铝合金铈化学转化膜的结构及耐蚀性研究

应用电化学方法及腐蚀试验研究了LY12铝合金表面常温稀土化学转化膜。结果表明，铝合金的稀土化学转化膜具有成膜温度低、速度较快、膜的耐蚀性能好等优点。电位－时间曲线表面，成膜动力学包括铝合金的溶解及随后的成膜两个过程。SEM表明，铝合金稀土化学转化膜的形态为片状，EDAX能谱表明转化膜主要由Ce,O,Al及少量的促进剂离子组成。腐蚀试验表明，未经处理的铝合金在3．5%NaCl溶液中经过21天浸泡后，表面出现了严重的点蚀，而经稀土处理的铝合金经过相同时间的浸泡后，表面只发生了轻微的均匀腐蚀，而未发生点蚀，浸泡后稀土处理的铝合金的失重较空白试样的下降了近1倍，铝合金的耐蚀性能大大提高。     

改性纳米氧化锆与水性聚氨酯复合涂层的防腐蚀性能

为了改进纳米氧化锆(ZrO_2)在涂料中的分散性,以丙酮为介质,用3-氨基丙基三甲氧基硅烷(APS)对纳米ZrO_2进行了改性,并在镀锡板表面制备了改性纳米ZrO_2/水性聚氨酯(WPU)复合涂层。通过扫描电镜、原子力显微镜、红外光谱、电化学测试、盐雾腐蚀、附着力测试等技术,研究了WPU与不同含量改性纳米ZrO_2复合涂层的防腐蚀性能。结果表明:改性纳米ZrO_2的含量为0.2%(质量分数)时,在WPU中的团聚现象消失,分散性良好,该复合涂层具有优良的耐蚀性和较大的附着力。