电镀锌钢板黑变机理的动力学

为探索铬酸盐钝化膜提高锌镀层耐蚀性的机理和研究其发生黑变的初期腐蚀现象， 对电镀锌钢板黑变的动力学规律进行了研究。以湿热实验中镀锌层表面明度差随时间变化的关系来表征钝化和未钝化试片腐蚀的速度， 发现钝化后的镀锌层的腐蚀规律符合Ｗａｇｎｅｒ 方程， 未钝化的镀锌层的腐蚀规律符合对数方程， 并求出了相应的腐蚀反应的活化能。钝化使腐蚀反应的活化能提高了一个数量级以上。实验结果表明该腐蚀是由于氧的向内扩散和锌离子的向外扩散， 钝化膜的存在影响了腐蚀的历程。     

电镀锌层表面黑变膜的研究

用ＳＥＭ、ＥＤＸ、ＸＲＤ、ＸＰＳ等技术分析了电镀锌层表面黑变膜的组成和结构。结果表明,黑变膜是锌的腐蚀作用及杂质Ｐｂ去极化作用的共同产物。它由ＺｎＯ、Ｚｎ５（ＣＯ３）２（ＯＨ）６及微量ＰｂＯ组成,膜表层Ｚｎ是以ＺｎＯ形态存在,而膜内层则以非化学计量化合物ＺｎＯ１－ｘ形态存在。并发现黑变膜是一种锌受腐蚀所形成的表面膜上产生的光干涉现象。     

热镀锌钢管表面黑变形成机理研究及解决方案探讨

研究了镀锌钢管表面黑变的机理及成因;通过中性盐雾试验和高温高湿试验,探讨了钢管表面黑变的解决方案.结果显示,钢管表面黑变成因与表面锌层中铅元素的含量及分布直接相关.铅含量较高区域腐蚀电位较高,铅含量偏低区域腐蚀电位相对较低.当有腐蚀介质存在时,会发生电化学腐蚀,使电位较低区域加快腐蚀,从而导致该区域腐蚀产物富集,氧元素...     

铅与光照对镀锌层黑变的影响

在硫酸盐镀液中所得的含铅与不含铅的镀锌试片，经铬酸盐钝化后，通过湿热试验（ＨＣＴ）进行了黑变培养，采用试片的表面明度差来表征黑变的程度，考察了铅和光照对其黑变速率的影响，发现镀液中铅离子的存在使黑变反应的活化能Ｅａ从３４ｋＪ／ｍｏｌ左右降低到２１ｋＪ／ｍｏｌ左右，从而加速了黑变反应。光照虽然使Ｅａ降低了０．５ｋＪ／ｍｏｌ，但同时较大幅度地降低了指前因子Ａ的值，总的作用结果是抑制了黑变的反应     

电沉积纳米镀锌层的机理研究

对电镀锌进行纳米改性研究，得到层状纳米镀锌层。采用场发射电镜(FEG-TEM)观察镀锌层结晶的形态，X衍射分析镀锌层晶粒的尺寸，恒电位法和电化学交流阻抗方法研究了纳米镀锌层的电沉积机理。     

预磷化电镀锌钢板性能指标对冲压成形的影响研究

以侧围外板零件为例，在分析复杂零件用材需求、冲压成形特征以及生产过程中零件报废率和材料性能对应性关系的基础上，深入探讨了零件高应变区域的变形特征和预磷化电镀锌钢板基本力学参数对该零件成形的影响。     

强度高而重量轻的电镀锌钢板

美国Posco钢铁公司开发成功一种590MPa（85ksi）高强度电镀锌钢板,用作汽车车身外皮,效益颇高。这种电镀锌钢板能耐高达60g／mm^2的负载,这比传统340MPa级汽车外皮用钢板要高70％之多,而且减薄了使用厚度并提高了抗压痕性能。由板材冲压制造汽车车身外皮,钢板的成形性和表面质量都大为提高,由于钢板厚度由0．7mm减薄到了0．55mm而使其重量减轻了大约20％。     

对含Mg磷酸盐处理电镀锌钢板的无铬密封处理

镀锌钢板在汽车车体压力成形时 ,由于容易发生压力裂纹和粘附问题 ,采取磷酸盐处理被膜可以改善其加工成形性能。此次日本川崎制铁公司研究所对含Ｍｇ磷酸盐处理被膜进一步采取无铬密封处理 ,并取得结果。试验材共选择 5种电镀锌钢板 :锌含量 3 0 ｇ/ｍ2(ＥＧ) ,在ＥＧ基体上添加Ｍｇ离子磷酸盐处理 ,其附着量 1.5 ｇ/ｍ2 ,Ｍｇ含有率 4.2 % (Ｐ ＥＧ) ,在此基础上涂覆含Ｍｇ离子 0 .4～ 0 .5 ｇ/ｍ2 (Ｓ Ｍｇ)和涂覆硅酮树脂0 .12～ 0 .2 ｇ/ｍ2 (Ｓ Ｓｉ)以及涂覆石腊 0 .1～ 0 .2 ｇ/ｍ2 (Ｓ ＳｉＷ ) ,将它们制成试样 ,然后进行滑动试验…     

Effects of plating factors on morphology and appearance of electrogalvanized steel sheets

Because the lightness, the gloss and the press-formability of electrogalvanized steel sheets change depending on the morphology of deposited Zn, control of this factor is essential to improving these properties. The effects of plating factors on the morphology of deposited Zn were systematically discussed both from the crystallographic viewpoint of epitaxy between Zn and steel and from the electrochemical viewpoint of the overpotential for Zn deposition. Plating factors include crystal orientation of steel substrate, current density, flow rate, temperature, addition of inorganic compounds to the solution and pre-adsorption of organic compounds. These plating factors affect the overpotential for Zn deposition and epitaxy between Zn and steel. The crystal orientation index of the Zn basal plane and the platelet crystal size of Zn are decreased with increasing the overpotential for Zn deposition. They are also decreased with decreasing the epitaxy between Zn and steel, even when the overpotential is kept constant. When the overpotential for Zn deposition is increased, the surface roughness of deposited Zn increases because of an increase in the inclination of the Zn basal plane to the steel substrate. When the epitaxy between Zn and steel is decreased without changing the overpotential, the surface roughness is reduced due to the decrease in platelet crystal size of Zn, although the inclination of the Zn basal plane is somewhat increased. The lightness of deposited Zn is enhanced with decreasing the surface roughness of Zn.     

Research of silane film cooperation with ZrO2 on electrogalvanized steel

The silane composite film formed on electrogalvanized steel sheet by silane film with ZrO2 improve the corrosion resistance.The surface morphology,the structure and composition as well as the corrosion resistance of the prepared silane composite film were investigated by SEM,AFM,XPS and electrochemical test.The experimental results showed that the structure of the silane composite film was composed of Si-O-Si three-dimensional network doped with ZrO2 showing excellent corrosion resistance,because the structure of this kind of composite film has much less micropore which improves the uniform and density of the silane film.improves the uniform and density of the silane film.     

电镀锌板表面斑状缺陷形成机理分析

采用扫描电镜对电镀锌板表面一类斑状缺陷从微观组织及成分等角度进行了分析,对其形成机理进行了探讨。结果表明:电镀锌板表面缺陷呈被局部碾压形貌,且缺陷部位粘附大量小黑点,小黑点的微区成分主要由C、O、Mg、S、Ca、Si、Mn等组成。通过产线排查及特征元素追溯发现缺陷来自于连续退火基板,导致缺陷产生的根本原因是富集在连续退火线水淬槽及与其相连水管内壁的水垢类异物粘附在板面上。通过清理连续退火线水淬槽及相连水管内壁后,基板表面质量得到控制,缺陷得以消除。     

Effect of additives on the properties of phosphate conversion coating on electrogalvanized steel sheet

Ni²⁺ and Mn²⁺ ions have been added separately to the phosphate solution to minimize the porosity of the phosphate conversion coating on electrogalvanized steels. Results showed that the Ni²⁺ or Mn²⁺ in the solution reduced the grain size and porosity of the phosphate coating; thereby, the corrosion resistance was enhanced. However, Ni²⁺ and Mn²⁺ played a different role in the coating formation. Ni²⁺ in the solution was reduced by Zn to form Ni, which enhanced the dissolution of Zn to promote the nucleation of hopeite grains. Mn²⁺ in the solution facilitated the nucleation by increasing the impingement of reacting species.     

镀锌钝化后白色斑点的形成机理及解决措施

为提高镀锌板表面耐腐蚀性,一般采用铬酸盐钝化,镀锌板钝化后出现细小白色斑点,同过对其形貌结合钝化理论以及钝化机理进行分析,基本确定了其形成机理;并根据现场工艺确定了解决方法。     

Development of a Molybdate-Phosphate-Silane-Silicate (MPSS) coating process for electrogalvanized steel

Electrogalvanized steel samples have been treated in a solution containing molybdate, phosphate and silicate and in the same solution containing silane and nitric acid as additives. The corrosion resistance of the treated samples has been compared to that of bare samples after exposure to 0.5 N NaCl for 24 h using polarization curves and EIS data. The chemical composition of the coating layers has been determined using different surface analysis techniques. The samples have also been exposed to the salt spray test. The results of these tests suggest that the MPSS treatment is a promising candidate for replacing conventional chromate treatments.     

The effect of an artificially synthesized simonkolleite layer on the corrosion of electrogalvanized steel

Electrochemical behavior of low alloy steel covered by a synthetic layer of simonkolleite was studied alone and in galvanic couple with zinc. Simonkolleite on steel inhibits cathodic oxygen reduction in 5 wt.% NaCl at pH = 7 and 9 but it is unstable at pH = 11. In NaCl solution the galvanic current density between Zn and steel is reduced by more than twice if the synthetic simonkolleite layer is deposited on steel. The polarity between Zn and steel is inverted after several hours in NaHCO₃ solutions. X-ray diffraction confirmed the instability of simonkolleite in this conditions and its transformation into carbonate containing salts.