锌层对镀锌钢板力学性能指标的影响

通过对热镀纯锌、电镀纯锌、预磷化电镀纯锌和热镀锌铁4种钢板去锌前后力学性能的对比研究，定量分析了锌层对镀锌钢板力学性能指标的影响规律。在此基础上探讨了镀锌钢板冲压成形的变形机理，结果显示：与电镀纯锌、预磷化电镀纯锌和热镀纯锌镀层相比，锌铁合金镀层的延展性较差，变形过程中镀层和基板之间的不协调显著降低了钢板的整体成形性能。     

钢板热镀55%Al-Zn层的耐盐水腐蚀性能

采用全浸、半浸和盐雾等试验方法研究了钢板热镀55 %Al-Zn合金镀层在3%NaCl的盐水溶液中的腐蚀行为.观察分析了镀层的组织结构和在盐水中 腐蚀后的表面形貌及腐蚀产物,阐述了镀层在盐水中的腐蚀过程和机理.结果表明55%Al-Zn 合金镀层比Zn镀层更耐蚀,并同样具有Zn镀层对钢基体的保护能力.     

镀锌层重量对其生长规律的影响

采用场发射扫描电镜(SEM)、能谱分析仪(EDS)分析了不同镀锌层重量下镀锌层微观组织及相分布情况。结果表明,镀锌层重量为80、120 g/m²,镀锌层中的δ相呈栅栏状,ζ相从疏松状变为致密状;而镀锌层重量为275 g/m²时,镀锌层中的δ相呈致密状,ζ相呈疏松状。3种镀锌层重量下的δ相厚度占总厚度的比例最少,且各相厚度与镀锌层重量呈正比关系。当镀锌层重量较小时,锌层表面疏松多孔,有类似晶界的沟槽;随着镀锌层重量的增加,镀锌层表面变得致密平整,沟槽深度明显变浅变少。因此镀锌层重量影响其微观组织结构,进而影响锌铁合金的相结构。     

Service Performance Evaluation of Graphene Modified Heavy Anticorrosive Coating on the Surface of Transmission Tower under Harsh Marine Atmosphere Corrosive EnvironmentEI北大核心CSCD

目前国家电网输电铁塔普遍采用镀锌钢进行施工建设,钢材表面镀锌层可以抑制基体腐蚀,保障输电铁塔长期安全服役。但在沿海地区的苛刻海洋工业大气腐蚀环境中,输电铁塔表面镀锌层易发生快速腐蚀失效。研制一种低表面处理石墨烯改性重防腐涂料体系,包括低表面处理石墨烯防腐底漆、环氧石墨烯阻隔中间漆和聚氨酯耐候面漆。通过实验室性能测试、 环境考核试验和示范工程涂装,对其服役性能进行综合评价。结果表明：研制的石墨烯改性重防腐涂料具有良好的隔水性和低表面处理施工性能,复合涂层耐盐雾性能超过 5 000 h,耐循环老化 4 200 h 后漆膜完整。在国网宁波供电公司北坞 2321 线 10 级输电铁塔示范涂装 54 个月后,石墨烯改性重防腐涂层光泽度降低,漆膜变色 1 级,百格附着力在 0~1 级,拉拔附着力 8.56~11.37 MPa。根据室内模拟加速试验和实际工程服役性能测试结果,研制的石墨烯改性重防腐涂料对输电铁塔在苛刻海洋大气腐蚀环境下的综合防护寿命可达 10 年以上。研究了石墨烯改性重防腐涂料体系的实际服役性能,实现在苛刻海洋大气腐蚀环境中对输电铁塔的长效腐蚀防护,为电网设施的长期腐蚀防护提供可靠途径。     

镀锌板上丙烯酸树脂复合膜的制备和表征

在镀锌钢板表面制备了丙烯酸树脂复合膜,用扫描电子显微镜观察膜层的微观形貌.用傅里叶变换红外光谱表征膜层的分子结构,用中性盐雾试验和电化学方法测试其耐蚀性,并用划痕浸泡实验测试膜层的自修复性能.结果表明:丙烯酸树脂复合膜表面致密平整;耐中性盐雾腐蚀达72 h;阻抗值和极化电阻值均较大,说明丙烯酸树脂复合膜能有效抑制腐蚀电化学反应;划痕浸泡试验证明丙烯酸树脂复合膜具有自修复功能.成膜过程中碳酸锆铵能够和丙烯酸树脂分子上的羟基和羧基发生交联反应,形成互穿网络结构,提高膜层内部的交联密度,有效地阻挡外界环境的侵蚀,当膜层破损时钼酸盐和磷酸盐与锌反应形成难溶盐吸附在破损处,起到自修复作用.     

输电塔塔腿镀锌层电化学腐蚀性能研究

目的利用冷镀锌层进行输电塔塔腿防护和损伤修复。方法采用电化学腐蚀试验,并结合扫描电子显微镜等试验手段,研究输电塔塔腿镀锌层的耐腐蚀性能。结果在Na Cl和NaHSO_3溶液中进行电化学腐蚀时,镀锌层的腐蚀速率随着溶液pH的增大而下降,腐蚀电流密度减小,耐腐蚀性能逐渐变好。在pH为4的酸性溶液中,锌层表面凹凸不平,腐蚀产物主要是ZnSO_4。在中性和碱性溶液中,锌层溶解减弱,腐蚀后锌层表面较为平整,腐蚀产物呈针状或片状,腐蚀产物为ZnSO_4和Zn_5(OH)_8C_(12)·H_2O。结论在NaCl和NaHSO_3酸性溶液中,镀锌层腐蚀电位较低,腐蚀速度较快,镀锌层发生晶界腐蚀而使表面凹凸不平。随着pH值的增大,镀锌层腐蚀速度快速降低,在pH值为10的碱性溶液中,镀锌层腐蚀速度显著降低,耐腐蚀性能增强。     

热浸镀锌层表面钛盐转化处理的研究

研究一种热浸镀锌层钛盐化学转化处理技术,分析了钛盐溶液各成分及工艺参数对热镀锌层表面转化膜形成及耐蚀性能的影响,对钛盐转化膜层的表面形貌和元素组成进行了表征,分析了钛盐转化液的稳定性。结果表明:采用含TiOSO40.9g/L,C2H2O42.5g/L,磷化合物3.0g/L的转化液,在pH=1.3,温度25℃的条件下处理热浸锌试片5min,获得的试片防腐性能良好,盐雾实验时间达160h;用C2H2O4替代H2O2,可大大提高钝化液的稳定性。     

镀锌层破损输电杆塔用镀锌钢在干湿交替作用下的腐蚀行为

采用自制大气腐蚀模拟试实验装置,并结合电化学阻抗及开路电位测试技术,研究了在干湿交替作用下,不同破损面积的输电杆塔用镀锌钢在NaCl和NaHSO₃腐蚀介质共同污染下的腐蚀行为。结果表明,随着破损面积以及暴露时间的增加,电极的开路电位逐渐正移,同时电极的腐蚀速率也会随着破损面积的增加而增加,不同破损面积的样品的腐蚀速率在初期随暴露时间的增加而增加,后期逐渐减小。     

Morphology and characterization of the anodic coating on galvanized steels prepared by alternating currents

A novel technique for producing anodic coatings on galvanized steels was developed in this study. Several coloured coatings, with thickness varying from 20 to 50 μm, were produced by adding a specific transition metal salt to the basic electrolyte of silicate. The anodic coating was composed mainly of silicon, zinc, sodium and oxygen, doped with transition metal ions. Results from electron probe microanalysis and X-ray diffraction studies indicated that the island-like structure is silicon-enriched and that a fused glass structure is a major part of the anodic coating. The colour imparted to the anodic coating depended on the specific metal incorporated during its formation. The coating significantly increased the corrosion resistance of galvanized steels.     

彩色热镀锌工艺及镀层的抗蚀性能

通过镀液成分和工艺试验，筛选出Ｚｎ－Ｍｎ－Ｃｕ和Ｚｎ－Ｔｉ－Ｎｉ两种成分镀液，在一定的浸镀温度和冷却方式下，可以获得表面光滑，色泽均匀的彩虹，金黄，紫，蓝等彩色镀层。盐雾腐蚀试验表明；彩色热镀锌层比常规热镀锌层的耐蚀性能约提高一倍。     

镀锌无铬钝化产品生产工艺优化

环保型镀锌产品是未来发展的必然趋势,文章阐述了镀锌无铬钝化产品的生产工艺,结合无铬钝化涂覆工艺理论,通过生产试验分析,提出了工艺优化措施及其相关的重要控制点,从而保证了无铬钝化产品涂膜质量的稳定性,并取得了明显的效果。     

BH390钢热镀锌抑制层及其合金化镀层界面结构

利用SEM和TEM研究了铝含量不同的热镀锌镀层中抑制层的结构及抑制层在形成和生长过程中Zn-Fe-Al金属间化合物之间的反应过程;分析了铝含量不同的镀层合金化后镀层与BH390钢基体之间的界面结构。结果表明,随着锌液中铝含量的增加,镀层中抑制层的结构逐渐由晶粒粗大且不连续的Fe2Al5转变为晶粒细小相对致密的FeAl3。铝含量不同的热镀锌镀层在合金化过程中抑制层结构的变化和镀层中各相的形成及生长过程是不相同。随着锌液中铝含量的增加合金化镀层与钢基体界面结合处镀层结构的均匀性逐渐降低,在相同的合金化工艺条件下,随着锌液中铝含量的增加镀层的合金化时间延长。     

镀锌板在不同加速腐蚀环境下的腐蚀行为研究

目的研究中性盐雾环境、中性盐雾加周浸环境和中性盐雾加湿热环境下镀锌板的腐蚀行为,明确不同加速腐蚀试验环境对镀锌板腐蚀行为的影响。方法对镀锌板进行中性盐雾、中性盐雾加周浸、中性盐雾加湿热等不同类型的加速腐蚀试验,通过失重法、SEM、XRD以及极化曲线等方法,对比不同加速腐蚀试验类型对镀锌板腐蚀行为的影响。结果在三种加速腐蚀试验环境下,镀锌板的腐蚀过程基本相同:镀锌层及白色锌锈腐蚀、锌层破裂、锌层完全脱落、基体碳钢腐蚀。腐蚀产物都以Zn(OH)_2、γ-FeOOH、ZnO、Fe_2O_3等为主。三种环境下镀锌板的腐蚀都不均匀,不同位置的腐蚀情况存在一定差异。其中,中性盐雾环境下材料腐蚀情况最为严重,中性盐雾加周浸环境次之,中性盐雾加湿热环境下最轻。结论三种加速环境都是主要通过Cl~-在锌表面的沉降和溶解作用增强介质的导电性能,加剧锌层的腐蚀。在中性盐雾环境中,Cl~-浓度最高,试样腐蚀最严重。在中性盐雾加周浸环境中,SO_4~(2-)与Cl~-协同作用,腐蚀也较严重。而中性盐雾加湿热环境中,Cl~-被稀释,腐蚀情况最轻微。     

不同镀层产品的工艺性能与生产线设计

近20年来带钢连续热镀锌技术、装备以及相应的控制手段均得到了巨大发展,我国的镀锌产品已从单一的大锌花镀锌板发展到不同镀层产品,但是针对一些特殊镀层产品,我国尚处于研发阶段。因此结合国内外先进的热镀锌生产技术与生产线设计经验,探讨不同镀层产品的工艺性能与生产线设计具有重要意义。对不同镀层产品的化学成分、组织特点、物理性能及热浸镀工艺参数进行了对比分析;结合不同镀层元素的物理特性、氧化特性和与铁反应性对热浸镀过程的影响,以及镀层凝固特性对热浸镀工艺的要求,总结了不同镀层产品生产线实际参数设计,着重介绍了前处理设备、退火炉、锌锅、镀后冷却等关键设备选型配置。     

无铬耐指纹产品表面性能评定体系的建立与研究

为了更准确地评定无铬耐指纹产品的表面性能等级,通过色差分析和形貌观察,研究了纯锌及锌铝镁两种镀层耐指纹产品各项表面性能的表现差异和影响规律;在传统目测等级评定的基础上,构建了一套定量化的表面性能评定体系。研究结果表明:两种耐指纹产品均表现出优良的表面性能,并在耐指纹性、耐酒精性和耐溶剂性上无明显差异。相较于锌铝镁镀层耐指纹产品,纯锌镀层产品具有更优异的耐高温黄变性,但由于其镀层更容易在高温高湿条件下发生腐蚀,表现出相对较差的耐湿热性和耐黑变性。     

Corrosion resistance of electroplated Zn-Co alloy coating

By the NSS test and the test in SO2 gas atmosphere and detecting the φcorr-t curves, Rp-t curves and the cyclic voltammogram curves, the corrosion resistance of the electroplated Zn-Co alloy coating was studied. The corrosion resistance of the electroplated Zn-Co alloy coating is three times higher than that of the galvanized coating. Because the corrosion resistance of the Zn-Co alloy coating is especially remarkable in SO2 gas atmosphere, it is particularly fit to be used as a protective coating in industrial atmosphere. The reason why the Zn-Co alloy coating has such a high corrosion resistance is that its corrosive product has a comparatively great role in depressing the corrosive process.     

A two-step roll coating phosphate/molybdate passivation treatment for hot-dip galvanized steel sheet

A two-step roll coating passivation treatment employing phosphate followed by molybdate solutions has been performed on hot-dip galvanized (GI) steel sheet. The phosphate coating was primarily porous, amorphous Zn phosphate. A second step coating treatment resulted in more hemispherical Zn phosphate particles and the incorporation of molybdate ions and molybdenum oxide into the existing phosphate coating, giving rise to an improved corrosion resistance. The coating reaction during the second step roll coating treatment and the corrosion protection afforded by the second step molybdate treatment are discussed, with emphases on the comparison with the coating formed via immersion.     

Characterization of hot-dip galvanized coating on dual phase steels

This work explored the microstructure of continuous hot-dip galvanized zinc coating on two dual phase steels, focusing on the sample preparation methods for cross-sectional microstructure and Fe-Al intermetallic compound observation. Based on the microstructure revealed by proper method, we established a relationship between the annealing atmosphere and coating microstructure. The experimental results showed that the coating thickness and Fe-Al intermetallic compound's size are relevant to the annealing atmosphere. And the coexistence of Fe-Al intermetallic compound and Fe-Zn phase has proved indirectly that the aluminothermic reduction is working during hot-dip galvanizing.     

Microstructure of the coating and mechanical properties of galvanized chromium-rich martensitic steel

Protecting the modern high-strength steels against corrosion is a challenge because the coating technology must be compatible with forming and must preserve the mechanical performances. Batch galvanizing after hot stamping could provide a simple solution to this complex problem. A commercial high-strength martensitic steel containing 13 wt.% Cr, 0.35 wt.% Si, 0.3 wt.% Mn and 0.15 wt.% carbon has been galvanized with a commercial zinc alloy. Galvanizing produces a ~ 15 μm thick coating that is bright, continuous and metallurgically bonded. The intermetallic layer is made of ? crystals, which forms an open 3-dimensional structure. Tin, nickel and aluminium are found able to moderate the Sandelin effect. Comparison with other steels galvanized the same way indicates that chromium slows down the kinetics of the metallurgical reaction. Chromium distributes both in the ? and η phases, and follows a diffusion-like profile in the coating. The nickel from the alloy concentrates in the Fe-Zn intermetallic compound. Aluminium segregates at the surface and interface. It also provides a gettering effect that fixes silicon in sub-micron particles dispersed in the ? and η phases. Tensile experiments and fatigue tests demonstrate that the mechanical performances of the martensitic steel are preserved after coating. Comparison with similar experiments performed on a TRIP800 steel indicates that using galvanized martensitic steel is best worth in static applications.     

Effect of Fe-Zn alloy layer on the corrosion resistance of galvanized steel in chloride containing environments

In this study, the effect of Fe-Zn alloy layer that is formed during galvanizing process on the corrosion behavior of galvanized steel has been investigated. The galvanostatic dissolution of galvanized steel was carried out in 0.5 M NaCl solution to obtain the Fe-Zn alloy layer on the base steel. The alloy layer was characterized to be composed of FeZn₁₃, FeZn₇ and Fe₃Zn₁₀ intermetallic phases, which constitute the zeta, delta1 and gamma layers of galvanized steel, respectively. It was observed that the alloy layer has similar cathodic polarization behavior but different anodic polarization behavior compared to galvanized steel. The anodic current plateau of alloy layer was up to 100 times lower than that of galvanized coating. Corrosion test performed in wet-dry cyclic condition has shown that the alloy layer has lower corrosion rate as compared to galvanized steel. From the results of corrosion test of alloy layer and base steel, it was concluded that Zn²⁺ has positive effect on the protectiveness of the zinc corrosion products. The measurement of surface potential over the alloy/steel galvanic couple has confirmed the galvanic ability of alloy layer to protect both the alloy layer itself and the base iron during initial stage of atmospheric corrosion.