环氧有机涂层对锌铁合金镀层耐蚀性的影响

利用腐蚀浸泡实验、失重法和交流阻抗谱分析等方法研究了环氧有机涂层对Q235钢电镀锌铁合金镀层耐蚀性的影响。结果表明,Q235钢基体、Q235+Zn–Fe合金镀层试样和Q235+Zn–Fe合金镀层+环氧有机涂层试样在5%NaCl溶液中浸泡504 h后,腐蚀速率分别为0.068 0、0.040 0和0.018 0 mm/a。涂覆环氧有机涂层至少能使锌铁合金镀层的防腐性能提高2倍,从而延长基体材料的使用寿命。     

锌铝镁镀层于3.5%NaCl溶液中腐蚀行为的研究

使用扫描电镜及扫描探针分析了锌铝镁镀层的表面形貌及成分,使用X射线光电子能谱仪及电化学技术分析了锌铝镁镀层腐蚀产物的化学组成、电化学性能,对锌铝镁镀层的耐蚀机制进行了探讨,结果表明:锌铝镁镀层主要由初生锌相、富铝相及共晶组织组成,Mg元素主要分布于共晶组织中。在3.5%NaCl介质腐蚀过程中,锌镀层腐蚀产物主要由Zn₅(CO₃)₂(OH)₆及ZnO组成,锌铝镁镀层腐蚀产物主要由Mg(OH)₂、4MgCO₃·Mg(OH)₂及Zn₅(CO₃)₂(OH)₆组成。锌镀层腐蚀产物电荷传输电阻逐渐降低,而锌铝镁镀层腐蚀产物电荷传输电阻逐渐增大,且后者大于前者。即锌镀层腐蚀产物无法抑制镀层的腐蚀,而锌铝镁镀层腐蚀产物则可以对镀层电化学反应起到抑制作用,对镀层提供一定程度的保护。     

Al-Si镀层和Al-Zn-Si合金镀层的缝隙腐蚀

应用电化学技术,研究了Al-1.6％Si镀层和55％Al-Zn-1.6%Si合金镀层,在3％NaCl溶液中的缝隙腐蚀历程。试验表明,55％Al-Zn-1.6%Si合金镀层,耐缝隙腐蚀优于Al-1.6%Si镀层;钝化处理后,两类镀层的缝隙腐蚀孕育期延长,缝内外偶合电流减小,耐缝隙腐蚀性能有较大提高。     

浅谈影响锌镀层耐蚀性的因素

1　前言镀锌层能很好地防止黑色金属腐蚀 ,有着广泛的应用。在我厂生产的汽车门锁产品中几乎都采用镀锌。但是零件在库存时却常常发生镀层变色、腐蚀等现象 ,造成了产品大量的返修 ,不但增加了成本 ,还影响了工厂的形象。2　原因分析2 .1　操作不当镀层粗糙 ,零件在出镀槽和钝化后清洗不彻底 ;没有烘干 ;老化温度过高造成钝化膜龟裂 ;镀液温度过高等都会造成镀层抗蚀能力差。应严格控制工艺参数和操作要求。2 .2　镀层中含有过多的重金属和有机杂质可定期用双氧水、锌粉及活性炭处理 ,过滤镀液。锌镀层纯度越高 ,结构越均匀 ,抗蚀能力越强。…     

水性环氧改性丙烯酸防火磁漆的制备

以丙烯酸、丙烯酸丁酯、甲基丙烯酸甲酯、丙烯酸2,4,6-三溴苯酯和环氧树脂（E-44）等为原料合成了水性环氧改性丙烯酸树脂,讨论了丙烯酸2,4,6-三溴苯酯的含量对涂层阻燃性能的影响,E-44、丙烯酸的含量以及中和度对水性环氧改性丙烯酸树脂性能的影响。讨论了阻燃助剂等对涂层阻燃性能的影响。     

热镀锌及锌铝镁合金钢在不同大气环境下的腐蚀行为

选用热镀锌(GI)钢和热镀锌铝镁合金(ZM)钢,分别在吐鲁番、江津、青岛和万宁4种典型环境地区中进行大气腐蚀试验。通过分析镀层腐蚀后的形貌、微观组织结构和腐蚀产物成分,探究了纯Zn镀层和Zn–Al–Mg合金镀层在不同大气环境下的腐蚀行为。结果表明,在相同大气环境下服役时,ZM具有比GI更优异的耐蚀性。两者在干燥大气中的腐蚀速率都较低,在潮湿工业大气环境和近海高氯大气环境中的腐蚀速率较高,腐蚀产物以Zn(OH)₂、ZnO、ZnCO₃及Zn₅(CO₃)₂(OH)₆为主。     

盐酸介质中镍基合金镀层的电化学腐蚀行为

在含有硫酸镍、钨酸钠和柠檬酸三铵的电解液中获得镍一钨合金电沉积层。在分别含有二甲基胺硼烷和二氧化锆粒子的上述电解液中,电沉积获得Ni—W—B合金和Ni—w—(ZrO2)复合镀层。采用电化学实验方法研究所获得的Ni—W、Ni—W—B和Ni—W—(ZrO2)镀层在盐酸介质中的腐蚀行为,结果表明：所获得的镀层均有较好的耐蚀性;Ni—W和Ni—W—B镀层比Ni—W—(ZrO2)镀层有较好的抗腐蚀能力。     

改进的线性极化法测定锌镀层的腐蚀速率

将函数记录仪引入至小幅值、超低频电位方波线性极化法中,并依据其特点,测定了锌镀层的腐蚀速率。结果与失重法和中性盐雾试验法相比,有较好的一致性。     

Al－1．6％Si镀层和55％Al－Zn－1．6％Si合金镀层的缝隙腐蚀

应用电化学技术研究了Ａｌ－１．６％Ｓｉ镀层和５５％Ａｌ－Ｚｎ－１．６％Ｓｉ合金镀层在３％ＮａＣｌ溶液中的缝隙腐蚀历程。试验表明５５％Ａｌ－Ｚｎ－１．６％Ｓｉ合金镀层耐缝隙腐蚀优于Ａｌ－１．６％Ｓｉ镀层；钝化处理后，两类镀层的缝隙腐蚀孕育期延长，缝内外偶合电流减小，耐缝隙腐蚀性能有较大提高。     

酸性锌-镍合金镀层与碱性锌-镍合金镀层的性能比较

比较了酸性锌-镍合金镀层与碱性锌-镍合金镀层的性能。结果表明:酸性锌-镍合金电镀工艺较碱性锌-镍合金电镀工艺具有更高的镀速,但均镀能力较差。在相同的外部控制条件下,酸性锌-镍合金镀层和碱性锌-镍合金镀层的耐蚀性及结合力相当。     

Corrosion electrochemical behavior of epoxy anticorrosive paints based on zinc molybdenum phosphate and zinc oxide

Electrochemical impedance spectroscopy (EIS) was applied as a principal tool to describe the efficiency of anticorrosive epoxy paints (primers) based on zinc molybdenum phosphate (ZMP) pigment. Steel-coated samples were exposed to a 0.5 M NaCl solution. During the study the corrosion potential (E_oc) and R_p values also were monitored every 24 h. It is discussed the incorporation of micronized ZnO (1 μm) pigment to the base mixture and its positive, reinforcement effect on the protective properties of ZMP primer. The explanation is related to the izoelectric point (IEP) of ZnO particles (pH < 9), which determines their positive surface charge and electrostatic attraction with the molybdate anion. In this case the charge of the formed double layer capacitor is very high. Moreover, the mentioned attraction inhibits and saves ZnO particles from their rapid dissolution to hydroxide.     

温度对硫酸盐镀锌层性能的影响

通过金相显微镜、极化曲线测量和明度测试,分析了温度对硫酸盐镀锌体系(锌离子90 g/L,硫酸6 g/L,电流密度5 A/dm2,温度30~70°C,时间475 s)在低碳钢上所得镀层形貌和性能的影响。结果表明,温度对镀锌层明度、微观形貌及耐蚀性影响较大。升高温度可降低浓差极化,有利于镀层结晶,表现出好的明度和耐蚀性;但温度过高,电化学极化减弱,所得镀层结晶粗大,明度和耐蚀性降低。温度为50°C时获得的镀层性能最好。     

锌合金压铸件电镀层起泡成因与消除对策

总结了锌合金组成、精炼、压铸条件、镀前处理与电镀层质量等因素对起泡缺陷的影响。明确了导致起泡问题的原因主要包括:压铸锌合金中铅、镉等杂质含量高;压铸模具设计、预热温度不当;打磨造成压铸件表面致密层被过度破坏及抛光产生过热而出现表面惰性区;除蜡除油清理不彻底;打底电镀过程中出现置换镀;多层电镀的孔隙中含镀液。认为要大幅度降低锌合金压铸件电镀起泡率,需在生产过程中进行多点全面质量监控,定期抽样检查,特别是镀前表面质量及初始镀层置换镀和覆盖率的监测。     

镀锌层单宁酸钝化膜的耐蚀性

为提高镀锌层的耐蚀性,以氟钛酸钾、双氧水、硝酸为辅助成分,制备了单宁酸钝化液,并对低碳钢上的碱性镀锌层进行了钝化处理.通过质量分数为5%的NaCl溶液浸泡试验,确定了最佳钝化液组成和钝化工艺条件为:单宁酸40 g/L,HNO3 5 mL/L,氟钛酸钾10g/L,H2O2 60 mL/L,温度25℃,时间20～30 s....     

Preparation of epoxy–clay nanocomposite and investigation on its anti-corrosive behavior in epoxy coating

An epoxy–clay nanocomposite was synthesized using a quaternary ammonium-modified montmorillonite clay and diglycidyl ether of bisphenol A (DGEBA) type epoxy resin, in order to produce anti-corrosive epoxy coating. Anti-corrosive properties of the nanocomposite were investigated using salt spray and electrochemical impedance spectroscopy (EIS) methods. The results showed an improvement in the barrier and anti-corrosive characteristics of epoxy-based nanocomposite coating and a decrease in water uptake in comparison with pure epoxy coating. Wide-angle X-ray diffraction (WAXD) patterns and transmission electron microscopy (TEM) analysis showed that the interlayer spacing of clays increased after addition of epoxy resin along with applying shear force and ultrasound sonicator. The best performance of this coating was achieved at 3 and 5 wt.% clay concentration.     

影响复合电镀层中微粒复合量的因素

镀层中微粒的含量对复合镀层的性能有着重要的影响.本文综述了复合电镀中微粒复合量的影响因素,包括镀液中微粒含量、微粒尺寸、表面活性剂、电流、pH、镀液搅拌强度等,阐述了各因素对微粒沉积量的作用规律.     

Electrochemical and anticorrosion behavior of functionalized graphite nanoplatelets epoxy coating

Functionalized graphite nanoplatelets (FGNP) were used as efficient and compatible nano-particles to produce homogenous epoxy nano-coating with impressive anticorrosion behavior for carbon steel. The characterizations of the nano-particle and nano-coating were carried out by SEM, FT-IR, XRD, TEM and pull-off test. Fine distribution of nano-particles in the cured nano-coating with particle sizes of 20–40 nm was obtained. Electrochemical experiments, salt spray and X-ray fluorescence showed that the nano-coatings protect the metal substrate by formation of passive layer and physical barrier characteristics. Three samples (0.25%, 0.5% and 1%) of FGNP-epoxy coatings were prepared that 0.5% showed better anticorrosion properties.     

磷化碳钢上聚四氟乙烯涂层腐蚀行为

以20#碳钢样片为基底材料,采用浸渍提拉法,在经磷化的碳钢样片基底上,制备了膜厚为13(±2)μm的聚四氟乙烯疏水涂层,并对其物理化学性能和腐蚀情况进行了表征.结果表明,普通的磷化碳钢表面,其磷化颗粒晶体尺寸比较粗大,且颗粒分布不均匀;采用磁力搅拌的磷化碳钢表面,其磷化颗粒晶体尺寸细小而致密.所制备的磷化膜由Zn3(P...     

Corrosion resistance and dielectric properties of an iron oxide filled epoxy coating

Polymeric composites of a bisphenol-A-epoxy resin and iron oxide filler (15% w/w) were deposited on pretreated steel specimens. The applied coatings had a thickness of 80 μm and 220 μm. The modification of the anticorrosive and dielectric characteristics of these coatings, in a corrosive environment (3.5% NaCl), were monitored by potentiodynamic polarization measurements, electrochemical impedance spectroscopy, and dielectric measurements. Corrosion resistance of composite coatings was found to be somewhat higher than that of unfilled epoxy coatings. Coatings containing iron oxide exhibited capacitive behavior as revealed by dielectric and EIS measurements. This behavior is more pronounced in high thickness composite coatings. Chemical Engineering Dept., Materials Science and Engineering Section. 9, Iroon Polytechniou Str., 15780 Athens, Greece. University of Veszprem, Physical Chemistry Dept., H-8201 Veszprem, Egyetem u. 10 POB 158, Hungary.     

Cathodic disbondment of epoxy coating with zinc aluminum polyphosphate as a modified zinc phosphate anticorrosion pigment

As an approach to improve the resistance of protective coatings to the disbondment, modification of the formulation through incorporation of zinc aluminum polyphosphate anticorrosion pigment representing third generation phosphates was examined in this paper. The data obtained from cathodic disbonding test, electrochemical impedance spectroscopy and pull-off indicated that introduction of zinc aluminum polyphosphate within epoxy coating could provide improved resistance to cathodic disbonding as well as superior adhesion strength. The superiority in the presence of the modified pigment was connected to deposition of a layer at the disbonding front and locally controlled pH as well. The precipitation restricting active zone available for electrochemical reaction was confirmed by SEM.