稀土元素对桥梁缆索用热浸镀Zn-10Al镀层钢丝耐蚀性能的影响

通过双镀法制备Zn-10Al-xRE(x=0.05,0.08,0.11,0.14,0.17)五种热浸镀锌铝镀层,并利用中性加速盐雾试验、电化学实验及扫描电子显微镜（SEM）分析其腐蚀形貌及耐蚀性能。结果表明,五种镀层在中性加速盐雾试验下,可保证基体在120d以内不被腐蚀,而纯锌镀层在30d时已经出现红锈,证明Zn-10Al-xRE的耐蚀性能可达到纯锌镀层4～5倍。Zn-10Al-xRE镀层钢丝的耐蚀性能随稀土含量的上升先升高再降低,添加0.08%RE的Zn-10Al镀层耐蚀性最好。用SEM对120d盐雾试验下的镀层钢丝进行观察,可以看出纯锌镀层的腐蚀产物较为疏松,Zn-10Al-xRE的腐蚀产物较为致密,Zn-10Al-xRE中腐蚀产物大约分为韧窝状、球状及针片状,耐蚀性能最好的Zn-10Al-0.08RE镀层中含有大量韧窝状腐蚀产物。     

稀土铈对热浸镀锌层耐蚀性能的影响

在锌浴中分别添加不同质量分数(0.00%~0.12%)的稀土Ce,获得了热浸镀Zn–Ce镀层。采用扫描电镜观察不同镀层的截面形貌,通过中性盐雾试验和测量电化学极化曲线及电化学阻抗谱,研究了Ce对锌镀层耐蚀性的影响。结果表明,稀土Ce对镀层结构无影响,但可在一定程度上控制Zn–Ce镀层的超厚生长。与纯锌镀层相比,Zn–Ce镀层经中性盐雾试验8 h后的白锈面积较小,且出现红锈的时间也延后,在5%NaCl溶液中的自腐蚀电位更正,电化学阻抗也更高。因此锌浴中Ce的添加可提高镀层耐蚀性。Ce的添加量为0.08%时,Zn–Ce镀层的耐蚀性最佳。     

热浸锌-钛合金镀层钢板的电化学行为

在纯锌浴中添加钛,制得锌-钛合金镀层含硅钢板.通过塔菲尔极化及电化学阻抗测量,研究了其在w=5%的NaCl水溶液中的腐蚀电化学行为,并与热浸纯锌镀层钢板进行了对比.结果表明,锌-钛合金镀层钢板的极化电阻和交流阻抗增大,腐蚀电流密度减小,耐蚀性能得到提高.     

热浸锌–钛合金镀层钢板的电化学行为

在纯锌浴中添加钛,制得锌–钛合金镀层含硅钢板。通过塔菲尔极化及电化学阻抗测量,研究了其在w=5%的NaCl水溶液中的腐蚀电化学行为,并与热浸纯锌镀层钢板进行了对比。结果表明,锌–钛合金镀层钢板的极化电阻和交流阻抗增大,腐蚀电流密度减小,耐蚀性能得到提高。     

钒含量对热浸Zn–0.05%Ni–V合金镀层组织与性能的影响

向Zn-0.05%Ni热浸镀浴中添加微量的钒,在硅含量为0.09%的钢上获得了Zn-0.05%Ni-V合金镀层,研究了V含量对镀层组织的影响.通过电化学阻抗谱、极化曲线和高温氧化实验,研究了纯Zn、Zn-0.05%Ni及Zn-0.05%Ni-V镀层的耐蚀性和抗氧化性.结果表明:在Zn-0.05%Ni镀浴中添加质量分数大于0.03%的钒可以有效抑制铁锌反应,控制ζ相层的超厚生长.与纯Zn和Zn-0.05%Ni合金镀层相比,Zn-0.05%Ni-V合金镀层在质量分数为5%的NaCI溶液中的电化学阻抗增大,自腐蚀电位更正,极化电阻增大,腐蚀电流密度减小,耐蚀性提高.Zn-0.05%Ni-V合金镀层的高温抗氧化性能优于纯Zn和Zn-0.05%Ni镀层.当钒含量为0.05%时,其表面形成了更为致密的氧化产物,具有最优的高温抗氧化性能.     

钒含量对热浸Zn-0.05%Ni-V合金镀层组织与性能的影响

向Zn-0.05%Ni热浸镀浴中添加微量的钒,在硅含量为0.09%的钢上获得了Zn-0.05%Ni-V合金镀层,研究了V含量对镀层组织的影响.通过电化学阻抗谱、极化曲线和高温氧化实验,研究了纯Zn、Zn-0.05%Ni及Zn-0.05%Ni-V镀层的耐蚀性和抗氧化性.结果表明:在Zn-0.05%Ni镀浴中添加质量分数大于0.03%的钒可以有效抑制铁锌反应,控制ζ相层的超厚生长.与纯Zn和Zn-0.05%Ni合金镀层相比,Zn-0.05%Ni-V合金镀层在质量分数为5%的NaCI溶液中的电化学阻抗增大,自腐蚀电位更正,极化电阻增大,腐蚀电流密度减小,耐蚀性提高.Zn-0.05%Ni-V合金镀层的高温抗氧化性能优于纯Zn和Zn-0.05%Ni镀层.当钒含量为0.05%时,其表面形成了更为致密的氧化产物,具有最优的高温抗氧化性能.     

Zr含量对热浸Zn–0.1%Ni–Zr合金镀层组织与耐蚀性的影响

在Zn–0.1%Ni锌浴中添加Zr元素,制备出Zn–0.1%Ni–Zr热浸镀层。通过扫描电子显微镜、电化学阻抗谱、电化学极化测量及中性盐雾试验,研究了Zr元素对镀层组织和耐蚀性能的影响。结果表明:与纯Zn和Zn–0.1%Ni镀层相比,Zr元素的添加不仅可以抑制ζ相的超厚生长,增厚致密δ相,使(δ+ζ)合金相层厚度明显减薄,而且可以使镀层的电化学阻抗和极化电阻增大,自腐蚀电位正移,腐蚀电流密度减小,延缓白锈的产生。在锌浴中添加0.06%Zr所得Zn–0.1%Ni–Zr合金镀层的(δ+ζ)合金相层减薄效果最佳,耐蚀性最优。     

稀土元素对机械镀锌层性能的影响

采用机械镀锌工艺,在镀层形成过程中添加某种稀土盐获得机械镀锌层。测定了镀层的电化学腐蚀参数、镀层孔隙率、元素谱线及镀层断面形貌。讨论了稀土含量对镀锌层电化学腐蚀性能、孔隙率的影响。研究结果表明:稀土能显著改善机械镀锌镀层的耐蚀性能和提高镀层的致密性;镀层耐蚀性随稀土添加量增加呈先提高后降低趋势;当稀土加入量为2%时,锌镀层耐蚀性最好,致密性最高。     

Zn-5%Al-RE镀层耐蚀性能的研究

试验了在高碳钢丝表面上热浸镀Zn-5%Al-RE合金层。通过湿热试验、晶间腐蚀试验、盐雾腐蚀试验，研究了该合金镀层的耐蚀性能，并与镀锌钢丝的耐蚀性能进行了对比。在水蒸汽的晶间腐蚀试验表明，合金镀层还略逊于锌镀层，但是在采用模拟海水的湿热试验以及盐雾腐蚀试验中，合金热浸镀层的耐蚀性能明显优于普通锌镀层，阳极极化曲线表明，合金层的致钝电流密度小，致钝电位较低，且稳定钝化区较宽，这可能是合金热浸镀层在海水中具有较好耐蚀性能的主要原因。     

硫酸高铈对低碳钢表面化学镀镍–锌–磷的影响

为了改善镍–锌–磷合金镀层的性能,在基础镀液中添加硫酸高铈,在低碳钢钢管表面进行化学镀镍–锌–磷合金。通过称重法和在5%Na Cl溶液中的耐蚀时间测试以及采用扫描电镜(SEM)、X射线衍射仪和电感偶合等离子体发射光谱仪(ICP-OES)考察了镀液中Ce(SO4)2浓度对镀速和镀层的表面形貌、耐蚀时间和晶体结构的影响。随着Ce(SO4)2浓度的增大,镀速和耐蚀时间先升高后下降,镀层的表面形貌和晶体结构先得到改善后劣化。适宜的Ce(SO4)2用量为15 mg/L。与基础镀液比较,含15 mg/L Ce(SO4)2的镀液镀速从3.7 mg/(cm2·h)提高至4.4 mg/(cm2·h),所得镀层平整、光亮、均匀和致密,非晶相程度提高,耐蚀时间从240 h延长至275 h。     

热浸镀锌层表面钛盐转化膜研究

利用钛盐成膜工艺在热镀锌层表面获得了色泽光亮、耐蚀性能优良的银白色转化膜层。采用扫描电镜、能谱仪、电化学极化和盐水浸泡方法研究了钛盐转化膜层的表面形貌、元素组成和耐蚀性能。分析了钛盐溶液成分及工艺参数对热镀锌层表面转化膜的耐蚀性能影响。确定的最佳工艺条件为:Ti(SO4)21g/L,H2O260mL/L,pH0.5～1.0,处理温度25～30°C,处理时间10min。热镀锌层经此工艺处理后,耐蚀性能明显提高。     

Adhesion characteristics and corrosion stability of epoxy coatings electrodeposited on phosphated hot-dip galvanized steel

The influence of hot-dip galvanized steel (HDG) surface pretreatment with phosphate coatings on the corrosion stability and adhesion characteristics of epoxy coatings electrodeposited on HDG steel was investigated. Phosphate coatings were deposited on hot-dip galvanized steel from baths with different concentrations of NaF (0.1, 0.5 and 1.0 g dm⁻³) and at different temperatures (50, 65 and 80 °C). The influence of fluoride ion concentration in the phosphating bath, as well as the deposition temperature of the bath, on the adhesion characteristics and corrosion stability of epoxy coatings on phosphated HDG steel was investigated. The dry and wet adhesions were measured by a direct pull-off standardized procedure, as well as indirectly by NMP test, while corrosion stability was investigated by electrochemical impedance spectroscopy (EIS).     

热浸镀锌层表面偏钒酸盐转化膜

在热浸镀锌试样表面获得了一层均匀、完整的偏钒酸盐转化膜.成膜溶液成分及工艺条件为:NaVO3 5 g/L,pH 1.3,温度30 ℃,时间30 min.对比研究了偏钒酸盐转化膜和铬酸盐转化膜的耐蚀性能.结果表明,偏钒酸盐转化膜由Zn、O、V等元素组成,热浸镀锌层经偏钒酸盐转化处理后电化学阻抗和极化电阻增大,腐蚀电流密度...     

锡、镍对高硅钢表面热浸镀锌层生长的影响

研究了Zn-Sn和Zn-Sn-Ni浴中高硅钢(含Si0.36%)表面镀锌层的生长和微观组织变化,探讨了Sn和Ni抑制高硅钢镀层快速生长的原因。结果表明,含Sn锌浴能抑制高硅钢表面镀锌层的快速生长,抑制效果随锌浴中Sn含量的增加而增强。当锌浴中的Sn含量达5%时,高硅钢镀锌层的生长方式发生了改变,由反应扩散控制变为扩散控制。高硅钢在Zn-Sn或Zn-Sn-Ni浴中镀锌时,镀锌层的ζ/η界面形成了Sn或Sn和Ni富集区,在一定程度上阻滞了Fe-Zn扩散。锌浴中添加微量的Ni能显著减少Sn用量,当锌浴中Ni的添加量为0.06%时,Sn的用量可从3%降到1.5%。     

Corrosion behaviour of electrogalvanized steel in sodium chloride and ammonium sulphate solutions; a study by E.I.S.

Zinc and zinc-nickel (13% Ni) electrodeposits were passivated by dipping in chromate baths and characterized by scanning electron microscopy. The corrosion behaviour was studied using a.c. electrochemical techniques; electrochemical impedance spectroscopy (EIS) measurements were performed at open circuit and under galvanostatic control during the 24 h immersion time. In sodium chloride solution the zinc-nickel electrodeposits show a better corrosion resistance compared to the pure zinc coatings. During the immersion time, a surface nickel enrichment was observed which, together with the zinc corrosion products, acts as a barrier layer reducing the total corrosion rate. In the same solution the passivation treatment improves the corrosion resistance of the electrodeposits; nevertheless, on zinc substrates, the protection exerted by the chromate film is not, always effective during the immersion time. On the contrary the chromate coating on zinc-nickel substrates induces a remarkable and durable improvement of the corrosion resistance reducing the zinc dissolution almost completely. In the ammonium sulphate solution, the corrosion mechanism is significantly influenced by hydrogen reduction on the zinc-nickel surfaces, and by the production of a local surface acidity which is aggressive for the chromate coatings.     

A study of the corrosion resistance of a waterborne acrylic coating modified with nano-sized titanium dioxide

The incorporation of nano-sized inorganic pigment particles into organic coatings may offer the potential for improving many of their properties, including corrosion resistance, at relatively low loadings. In the present research, titanium dioxide with a crystallite size of 5-10 nm was added to a waterborne organic primer formulation at loadings from 0.1 to 5% (w/w) and applied to hot-dip galvanized steel (HDG) panels. The corrosion resistance of the modified coatings was measured by neutral salt spray corrosion testing and electrochemical impedance spectroscopy (EIS), with an unpigmented film tested for comparison. 3% (w/w) TiO₂ appeared to produce an optimum improvement in the corrosion resistance.     

Coil-coated steel: corrosion resistance and adhesion as a function of the composition of the intermediate galvanic layer

The corrosion behaviour of coil-coated steel (CCS) sheets with different intermediate zinc-based coatings was examined by electrochemical impedance spectroscopy (EIS). Corrosion tests were performed in a 0.5 M NaCl aqueous solution in contact with the air, at ambient temperature. The results of pull-off adhesion test are also presented. The impedance data show that the improvement in the protective behaviour of the composite system is connected with the higher resistance values for the samples in which aluminium was added to the galvanized layer, and the best results are shown by CCS with aluzinc (Zn-55Al). These effects have been related to differences in the adhesion of the organic coating to the underlying metal substrate, as determined from both non-exposed samples and samples exposed to the electrolyte solution.     

双镀锌铝合金镀层的组织结构和耐蚀性

采用“双镀法”在钢板表面热浸镀不同铝含量的锌铝镀层(Zn-5Al、Zn-11Al、Zn-17Al和Zn-23Al),利用扫描电镜和能谱仪考察浸镀液中铝含量对镀层组织结构的影响,采用电化学测试、中性盐雾试验等手段评价镀层耐蚀性的变化。随着浸镀液中铝含量升高,镀层表面由片层状交替排布的富铝、富锌共晶组织向富铝枝晶网络结构转变,耐蚀性逐渐提高。但铝含量过高(质量分数大于17%)会导致大量脆性Fe-Al-Zn金属间化合物生成,合金层厚度明显增大。     

热镀锌钢板纳米二氧化硅改性有机-无机复合膜

研究了热镀锌钢板纳米SiO2改性有机-无机复合膜,研究了不同的纳米SiO2的加入形式对膜层耐蚀性的影响,探讨了该复合膜中钒酸盐的缓蚀作用,该复合膜层具有良好的成膜性能和耐蚀性能.     

Phenol electropolymerization on phosphated mild steel via zinc electrodeposition

Phenol electropolymerization to polyoxyphenylene coatings on phosphated steel and phosphated galvanized steel, normally impossible under the conditions allowing effective coating formation on either steel or zinc, is activated by cathodic deposition of zinc. A critical zinc amount has been found to be necessary to suppress electrochemical processes competitive with electropolymerization and induce coating formation with nearly 100% efficiency. SEM analysis showed that this critical amount of zinc corresponded to the formation of a low number of zinc nuclei emerging at the surface of the phosphate layer, on which, however, polyoxyphenylene was formed as a continuous coating. A.c. impedance tests showed that initial barrier properties are worse for coatings grown on zinc-plated phosphated samples than for those grown on steel from the same solutions. However, the long term corrosion resistance is much better in the former case, the improvement being largely associated with zinc cathodic protection