表面硅烷预处理/环氧镁铝复合涂层体系对铝合金的保护性能

在 LY12铝合金表面制备了一层硅烷膜，研究了硅烷膜对铝合金表面富镁铝环氧涂层性能的影响。硅烷处理后，形成了硅烷膜与基体之间Si-O-Al共价键以及硅烷膜内部的Si-O-Si 结构，而硅烷膜中未成键的硅醇基团-OH 以及 R-的环氧基团与涂层中的有机组分反应成键或通过范德华力发生交联互穿，使铝合金基体与环氧镁铝复合涂层之间形成更加牢固的交联互穿网络结构（IPN），镁铝复合涂层在LY12铝合金基体上的附着力明显提高。马丘测试和电化学阻抗测试结果表明，硅烷处理改善了LY12铝合金表面镁铝复合涂层的整体屏蔽性能，使涂层体系的保护效果显著提高，保护时间延长。     

复合硅烷化预处理对铝合金/环氧胶粘剂粘接强度的影响

研究了铝合金表面复合硅烷化预处理对铝合金与环氧胶粘剂粘接强度和粘接耐久性的影响,并与铬酸盐预处理进行了比较。用反射吸收红外光谱和透射电镜分析观察铝合金表面复合硅烷化膜层的结构,分别用扫描电镜、X-射线光电子能谱和俄歇能谱分析了不同粘接件断裂表面。结果表明,铝合金经复合硅烷化预处理能明显提高铝合金基体与环氧胶粘剂的粘接强度和粘接耐久性。搭接件断面呈现一层层撕开的破坏现象,而铬酸盐处理的搭接断裂件的断面较平齐。硅烷化处理的楔子试样断裂件的断裂面也呈现明显的韧性断裂,表明在铝合金与胶粘剂界面区域形成的Al-O-Si和硅氧烷共价键网络和复合硅烷化膜层表面的环氧基团起着明显的界面和表面改性作用。     

铝合金表面复合硅烷化处理

西北工业大学研究了铝合金表面复合硅烷化处理对铝合金与环氧胶粘剂粘接强度和粘接耐久性的影响，并与铬酸盐处理方法进行了对比。实验结果表明，在铝合金与环氧胶粘刘界面区域形成的Al-O-Si和硅氧炕共价键网络及复合硅烷化膜层表面的环氧基团，起着明显的界面和表面改性作用。     

LY12铝合金表面硅烷杂化膜的电化学性能研究

以γ-缩水甘油醚基丙基三甲氧基硅烷(GPTMS)和甲基三乙氧基硅烷(MTES)为前驱体,制备了正硅酸乙酯(TEOS)改性溶胶,并在LY12铝合金表面制得了2种有机硅烷杂化薄膜.对裸铝合金、钝化膜和硅烷杂化膜合金电极进行了动电位极化曲线和电化学阻抗谱(EIS)测试,评价了各化学转化膜的防腐蚀性能.结果表明:有机硅烷杂化膜可有效提高铝合金的耐蚀性,其耐蚀效果与传统铝合金表面钝化膜相当,其中GPTMS/TEOS膜的性能更优于钝化膜.     

冷轧钢板表面氟锆酸盐-硅烷复合转化膜的制备与性能

采用有机硅烷协同氟锆酸盐复合制备出硅烷处理液,在冷轧钢板表面形成复合转化膜。通过硫酸铜点滴试验确定了较佳的配方组成为H2ZrF60.5g/L、γ-APS5g/L、ZnSO4·7H2O0.5g/L、GPS10g/L、OP-100.1g/L,浸泡时间5min。测试了所制硅烷转化膜的附着力和耐中性盐雾性能,并与德国某公司的硅烷处理液进行了对比。结果表明,该转化膜与环氧漆和聚氨酯漆有良好的结合力(附着力达到0级),涂层体系可通过504h中性盐雾试验,表现出与对比产品相当的性能,具有良好的市场应用前景。     

氟化石墨烯硅烷功能化对环氧复合涂层耐腐蚀性的影响

采用 γ-缩水甘油醚氧丙基三甲氧基硅烷（ GPTMS）对氟化石墨烯（ FG）进行功能化处理得硅烷功能化氟化石墨烯（ GFG）采用 XRD、FT-IR和 SEM对粉体进行表征；将 FG和 GFG分别加入环氧树脂中获得复合涂层，通过电化，学测试和 5%NaCl中性盐雾试验研究复合涂层的耐腐蚀性。结果表明： FG能有效地增加环氧涂层（EP）的长期耐腐蚀性， FG经过硅烷功能化处理后进一步提升了其与树脂之间的界面相容性，所得复合涂层的致密性进一步提高，从而显著提升了环氧复合涂层的耐腐蚀性。经 3. 5%NaCl溶液 4 000 h浸泡后， GFG改性环氧复合涂层（ GFG/EP）的低频阻抗模值相较于纯 EP涂层提升了 3个数量级，较 FG改性环氧复合涂层（FG/EP）提高了 1个数量级；同时盐雾腐蚀 90 d后， GFG/EP涂层表面无明显腐蚀现象。     

AZ91D镁合金磁控溅射镀铝膜及其化学转化后的耐蚀性

采用磁控溅射镀铝与化学转化复合处理的方法对AZ91D镁合金表面进行处理,制得复合处理膜层,并与单纯磁控溅射镀铝膜层的耐蚀性进行了比较。结果表明,磁控溅射所得铝膜层结构致密,铝膜层与镁合金基体界面形成混合过渡层。沉积铝膜后再进行阿洛丁化学转化所得膜层表面存在裂纹,化学转化膜与铝膜之间结合良好。磁控溅射铝膜层使镁合金的腐蚀速率加快。镀铝与化学转化复合处理所得膜层的腐蚀电流密度比镁合金基体低1个数量级以上,表明镀铝与化学转化复合处理可明显提高镁合金的耐蚀性。中性盐雾试验4h后,铝膜表面腐蚀严重;而复合处理膜层在试验24h后表面只出现少量的腐蚀,48h后只有5%的面积被腐蚀。     

金属表面改性硅烷化处理研究进展

硅烷化处理是以硅烷偶联剂为主要原料的新型表面处理技术,常用于涂装前处理以提高金属基体与有机涂层的结合力或将其直接作为防腐蚀涂层。单纯的硅烷膜膜层较薄、表面有缺陷及裂纹,影响了其对金属的防护性能,需要对其进一步改性。综述了近年来国内外对硅烷化处理改性工艺的研究,详述了各种改性工艺对硅烷膜性能的影响,对耐蚀机理进行阐述,指出各种改性工艺存在的不足并提出进一步的研究方向。双层硅烷膜、添加纳米粒子、无机缓蚀剂、有机缓释剂以及硅烷与树脂复配等工艺明显提高了硅烷膜的性能,将多种改性工艺相结合可得到综合性能更加优异的硅烷膜。但还需要进一步研究改性机理,提高硅烷膜对不同基体的适用性及与涂装体系的配套性。     

环氧／纳米ZnO复合涂层对镁锂合金耐腐蚀性的影响

以聚丙烯酰胺凝胶法制备了纳米ZnO,并对其进行改性,得到了环氧/纳米ZnO复合涂层.采用XRD和SEM对环氧/纳米ZnO复合涂层进行了表征.通过极化曲线和交流阻抗研究了裸基、复合涂层以及经锡酸盐转化处理后涂覆环氧/纳米ZnO的复合涂层的耐蚀性能.结果表明:复合涂层呈明显的两相结构,纳米ZnO分布均匀;复合涂层和锡酸盐转化协同,提高了镁锂合金的耐腐蚀性能.涂层中纳米ZnO质量分数不同,对镁锂合金耐蚀性能有不同的影响,纳米ZnO质量分数为2%时,复合涂层对镁锂合金的保护作用最强.     

基体残余应力对铝合金热控膜层的影响研究

本文研究了基体残余应力对铝合金热控膜层的影响,测试了不同热处理条件下2A12铝合金基体的残余应力,通过扫描电子显微镜对膜层的微观结构进行了分析,并对阳极氧化膜与基体结合强度及膜层的裂纹扩散进行了研究,分析了涂层残余应力形成机理。结果表明,铝合金消应力退火处理可以减轻阳极氧化膜的裂纹扩展情况。     

AZ91D镁合金表面不同树脂体系富镁涂层的保护性能

采用划叉浸泡实验,电化学交流阻抗(electrochemical impedance spectroscopy,EIS),开路电位(open circuit potential,OCP)及动电位扫描研究了不同类型的环氧树脂对于AZ91D镁合金的表面的富镁涂层的保护性能的影响。结果表明环氧618-593构成的富镁涂层防护性能较差;环氧6101-TY650制备的富镁涂层可明显改善涂层对破损处镁合金基体的保护作用,但涂层本身长期防护性能较差;环氧618-T31构成的富镁涂层对AZ91D镁合金的防护作用较强,适宜制备镁合金表面的富镁涂层。3种环氧涂料中加入镁粉颗粒制备的富镁涂层均可对缺陷处裸露的AZ91D镁合金基体提供保护,从而延长漆膜的破坏时间。涂层中的镁粉颗粒被激活后,为镁合金的基体提供了一定程度的阴极保护作用,减缓了镁合金基体的腐蚀。     

The effect of silane layer drying temperature on epoxy coating adhesion on silane-pretreated aluminum substrate

In this study, 3-glycidoxypropiltrimethoxysilane was used as an adhesion promoter to enhance the adhesion strength of epoxy coating on an aluminum (Al) substrate. Silane layer drying temperature was investigated as a factor that has an influence on the adhesion of polymeric coating on metal substrate and also on its performance in wet and corrosive environments. FTIR tests were carried out to study Al/silane interactions. Drying the silane layer at high temperatures formed a condensed siloxane layer that improved the bonding strength as well as the performance of the protective coating in corrosive environments. The highest dry and wet pull-off strengths were obtained at drying temperatures of 100 and 125°C, respectively.     

Water uptake of epoxy coatings modified with γ-APS silane monomer

Epoxy resin was modified by a silane monomer, γ-aminopropyltrimethoxy silane (γ-APS), and was used as the protective coatings for LY12 aluminum alloys. The aim of the modification is to reduce the water uptake of polymeric coatings. The water absorption of coatings was measured by coating capacitance method in 3.5 wt.% NaCl aqueous solution. The result indicates that water uptake of epoxy coatings modified with 1.0 wt.% γ-APS decreases compared with pure epoxy coatings, whereas larger amounts of sliane result in the deterioration in performance against water permeation, due to the excessive consumption of epoxide group in epoxy resin by amino-group in silane agent, thus reduce the cross-linking of epxoy coating as a result of presence of excessive curing agent (polyamide). T_g of silane-modified coatings increases slightly after immersion, extremely contrasting with that of pure epoxy coating, which was observed to decrease significantly after water permeation. The formation of Si–O–Si structure resulting from the hydrolysis and condensation of silane components during the immersion in aqueous media may be a reasonable explanation for the abnormal change in T_g of silane-modified coatings. In addition, all silane-modified coatings display better protection performance, which is characterized by higher charge transfer resistances (R_ct) and lower double layer capacitance (C_dl) at substrate/electrolyte interface.     

Cathodic Delamination of an Epoxy/Polyamide Coating from Steel

X-ray photoelectron spectroscopy (XPS) has been used to determine the mechanism responsible for debonding of an epoxy/polyamide coating from steel during cathodic delamination in 3.5% aqueous NaCl solutions. Coating failure always occurred near the interface between the coating and the oxide. The nitrogen content of the free surface of the prepared coatings was about 10%. However, the nitrogen content of the free surface dropped to only 5% after exposure to 1 N NaOH for four weeks and that of the coating failure surface after cathodic delamination was only about 2%, implying that the failure involved degradation of the polyamide curing agent by hydroxide ions formed at the steel surface by reduction of oxygen. That conclusion was supported by results obtained from curve fitting of C(1s) and O(1s) spectra. The intensity of components in the C(1s) spectra due to C—N and C≡O bonds in amide functional groups decreased significantly after coatings were exposed to NaOH or subjected to cathodic delamination. Small amounts of organic materials characteristic of the coating were observed on the substrate failure surface, perhaps indicating that the failure was cohesive within the coating but very close to the interface or that some products from degradation of the curing agent precipitated on the substrate. Use of silane coupling agents to retard cathodic delamination was also investigated. Coupling agents were added directly to the coating or applied to the substrate as a primer before application of the coating. Significant reduction in the rate of cathodic delamination was seen only when the silane coupling agent was applied to the substrate and cured at elevated temperatures before the epoxy/polyamide coating was applied.     

不同加速试验对环氧/聚氨酯涂层失效机制的影响

研究了模拟南海海洋大气环境下铝合金表面环氧锌黄/丙烯酸聚氨酯涂层体系的失效过程,通过循环加速、紫外/冷凝和中性盐雾的对比试验,探讨了在循环加速试验中紫外-冷凝试验和盐雾试验分别对复合涂层失效过程以及对聚氨酯面漆和环氧底漆失效机制的影响。结果表明,紫外-冷凝过程对丙烯酸聚氨酯面漆有较强的破坏作用,但对复合涂层体系整体的阻抗变化影响较小;紫外-冷凝过程中,位于面漆玻璃化转变温度范围内的试验温度,以及紫外光对氨基甲酸酯基团的破坏作用,是导致面漆发生破坏的主要原因。盐雾试验对面漆的失光率和色差变化影响不大,但连续的盐雾渗透对涂层体系的阻抗下降具有明显的加速作用,同时导致涂层与基材的附着力显著降低。相比单独的紫外-冷凝试验或盐雾试验,循环加速试验综合考虑了南海海洋大气中强太阳辐射、高温高湿、高盐分和温差等环境因素,能更准确反映南海大气环境中复合涂层的失效过程。     

7075铝合金表面硅烷化处理的研究

对7075铝合金进行了硅烷化处理,并对硅烷膜的厚度、吸水率、成分、形貌及耐蚀性等进行了分析。硅烷处理液通过水解和缩合反应形成Si-O-A1共价键,覆盖在铝合金表面形成硅烷膜。结果表明:硅烷膜表面均匀、致密,吸水率仅为0.763%。,厚度约为4um;铝合金经过硅烷化处理后,膜电阻至少增加了两个数量级,自腐蚀电位正移一0・331 V,自腐蚀电流密度降低了近两个数量级,耐蚀性明显提高。     

水性漆在汽车铝合金零部件上的应用研究

介绍了一种适用于汽车铝合金零部件的水性涂料,通过耐盐雾测试对比了不同涂料体系在铝合金上的防腐蚀性,同时探讨了膜厚、固化温度、助剂的选择对涂料耐腐蚀性能的影响。试验证明,新开发的水性双组分环氧涂料性能完全达到或超过现有溶剂型PU涂料。     

助溶剂对铝合金表面硅烷化预处理的影响

为了了解3-缩水甘油醚丙基三甲氧基硅烷(γ-GPTMS)溶液中助溶剂对水解的γ-GPTMS在铝合金表面的沉积特性的影响,用X射线光电子衍射(XPS)测定了不同助溶剂含量,不同γ-GPTMS浓度的溶液沉积在铝合金表面的硅含量,同时用反射吸收红外光谱(RAIRS)对铝合金表面膜层进行了表征,结果表明,助溶剂对γ-GPTMS在铝合金表面沉积有显著影晌,γ-GPTMS的纯水溶液在铝合金表面所形成硅烷化膜层的硅元素量最高,沉积量随溶液中γ-GPTMS浓度的增加而增加。另外,膜层与氧化的铝合金表面之间形成铝硅氧烷(Al-O-Si)共价键,而且γ-GPTMS分子中的烷氧乙基分布在膜层的外表面,具有较大的反应活性。     

Enhancement of Corrosion Performance of Epoxy Coatings by Chemical Modification With GPTMS Silane Monomer

In this paper, commercial epoxy resin was chemically modified by different amounts of 3-glycidoxypropyltrimethoxysilane (GPTMS) monomer using an organotin compound as catalyst, aiming to improve the anti-corrosion performance of epoxy coatings on 2024-T3 aluminum alloy substrate. Electrochemical impedance spectroscopy (EIS) was used to evaluate the barrier properties against water permeation and protectiveness of silane-modified epoxy coatings. The results showed that all the modified coatings presented higher barrier performance and better corrosion performance than pure epoxy coating, which were characterized by higher charge transfer resistance (R _ct) and lower double-layer capacitance (C _dl) at the electrolyte/metal interface. The improvements in corrosion performance and wet adhesion of modified epoxy coatings were also observed by the Machu test and boiling water test, respectively. Interestingly, it was found that the glass-transition temperature (T _g) of silane-modified epoxy coatings decreased only slightly during immersion in 3.5 wt% NaCl solution, in contrast with pure epoxy coating, which was observed to decrease significantly after water permeation. The corrosion performance of epoxy coatings was, thus, improved when the amount of chemically grafted silane monomer increased in the content range investigated in the present work.     

Molecular Structure of Polymer/Metal Interphases

The molecular structure of interphases in aluminum/epoxy and steel/epoxy adhesive joints was characterized using infrared spectroscopy. In one series of experiments, adhesive joints were prepared by curing beams of epoxy against aluminum or steel substrates. When the joints were cooled to room temperature, the residual stresses were sufficient for crack propagation along the interface. The adhesive and substrate failure surfaces were then analyzed with reflection-absorption infrared spectroscopy (RAIR), attenuated total reflection infrared spectroscopy (ATR) and X-ray photo-electron spectroscopy (XPS). When an epoxy/anhydride adhesive was cured against aluminum substrates primed with an aminosilane coupling agent, amide and imide groups were formed in the interphase. Chemical reaction between the primary amine of the primer and the anhydride of the curing agent precluded chemical bridge formation between the primer and adhesive. Metal cations from the 2024 aluminum substrate reacted with the anhydride to form carboxylate salts on the surface. When an epoxy/tertiary amine adhesive was cured against steel substrates, evidence of oxidation of the primary amine to imine was observed in the interphase.