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Colloid Chemistry of Meso Structures and Reactivity of Steel Rusts

细观结构的胶体化学和钢锈的反应性

基本信息

批准号：
13450296
负责人：
ISHIKAWA Tatsuo
金额：
$ 9.73万
依托单位：
Osaka Kyoiku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

1)Synthesized rustsThe aim of this research project is to elucidate the mechanism s of corrosion and corrosion resistance of steels, such as weathering steels.. The structures and formation of the rusts artificially synthesized were irvestigated by various techniques. Including in a point of colloid chemistry. To clarify the role of alloying metals in corrosion resistance of weathering steels, the rusts are synthesized from aqueous Fe salt solutions containing various metal ions. The influences of metal ions strongly depend on the kinds of metal ions and rust components. Most of metals added to weathering steels interfered with the crystalization and particle growth of rusts. It was shown that alloying with more than two kinds of metals is shown to be effective. Especially, the addition of Ti(IV) effectively controlled the formation of β-FeOOH which is formed in Cl^- environment, indicating that the alloying with Ti effectively reduces the corrosion of steels in marine and coastal dist … More ricts. The influences of anions such as chloride, sulfate, and phosphate on the formation and structure of rusts were also studied to investigate the effects of corrosion environment. The formation of β-FeOOH was markedly influenced by the presence of the anions.2)Rusts of weathering steelsThe rusts formed in different situations were characterized by nitrogen adsorption. The rusts on weathering steels exposed in different environments for 17 years were examined by nitrogen adsorption. The specific surface area of the rusts determined by nitrogen adsorption decreased with decreasing the air-born salinity, which means that the rust particles grow with the increase of environmental Cl^- and the corrosion resistance of steels is lowered in marine and coastal districts. The corrosion rate of the steels was increased with decrease of specific surface area, that is, increase of particle size. This result reveals that the compactness of rust layers relating to corrosion resistance of steels is lowered by the particle growth of rusts. It was shown that the rust particles grow with the progress of corrosion. The similar results were obtained on t the rusts on various steels exposed to different situations. Consequently, the adsorption method is useful for characterization of rusts, expecially particle size of rusts which can not be estimated by the other techniques.3)Rusts of galvanized steelsThe steel galvanized by Zn-alloys is an important material in various industries. The corrosion resistance of the galvanized steels is still not thoroughly explored. The mechanism of high corrosion resistance of the galvanized steels was investigated by using the synthesized rusts of Zn-alloys. The rusts of Zn-Al alloys which are widely used for galvanizing steels were sheet particles of simonkoleite on adding a small amount of Al(III) in ZnCl_2 solution. The sheet particles form the compact rust layers by preferred orientation. This fact well accords to a high corrosion resistance of steels plated with Zn-Al alloy in Cl^- environment. It is known that the steels galvanized by Zn-Al-Mg alloys show a high corrosion resistance in the presence of Cl^-. The rusts of Zn-Al-Mg alloys prepared from solutions of Zn-Al-Mg salts were fine sheet particles and formed more compact layers than those of Zn-Al alloys as confirmed by measuring the permeability of air into the rust layers. Less

1）合成锈该研究项目的目的是阐明钢（例如耐候钢）的腐蚀和耐蚀机制。通过各种技术研究了人工合成锈的结构和形成。包括胶体化学的一个点。为了阐明合金金属在耐候钢耐腐蚀性中的作用，由含有各种金属离子的铁盐水溶液合成铁锈。金属离子的影响很大程度上取决于金属离子的种类和铁锈成分。添加到耐候钢中的大多数金属都会干扰锈的结晶和颗粒生长。结果表明，与两种以上金属的合金化是有效的。特别是Ti(IV)的添加有效控制了Cl^-环境中β-FeOOH的形成，表明Ti的合金化有效降低了海洋和沿海地区钢材的腐蚀。还研究了氯离子、硫酸根和磷酸根等阴离子对锈的形成和结构的影响，以探讨腐蚀环境的影响。阴离子的存在对β-FeOOH的形成有显着影响。2)耐候钢的锈迹不同情况下形成的锈迹均通过氮吸附来表征。采用氮气吸附法对在不同环境下暴露17年的耐候钢的锈蚀情况进行了检测。氮吸附测定的铁锈比表面积随着空气中盐度的降低而减小，这意味着铁锈颗粒随着环境Cl^-的增加而长大，海洋和沿海地区钢材的耐腐蚀性能降低。钢的腐蚀速率随着比表面积的减小（即颗粒尺寸的增大）而增加。该结果表明，与钢的耐腐蚀性有关的锈层的致密性因锈颗粒的生长而降低。结果表明，锈粒随着腐蚀的进行而生长。对暴露于不同情况下的各种钢材的锈蚀也得到了类似的结果。因此，吸附法对于铁锈的表征非常有用，特别是铁锈的粒径，这是其他技术无法估计的。3）镀锌钢的铁锈锌合金镀锌钢是各个行业的重要材料。镀锌钢的耐腐蚀性尚未得到彻底研究。通过使用锌合金的合成锈，研究了镀锌钢的高耐腐蚀性能的机理。广泛用于镀锌钢的Zn-Al合金在ZnCl_2溶液中添加少量Al(III)后，其锈层为硅锰矿片状颗粒。片状颗粒通过择优取向形成致密的锈层。这与镀Zn-铝合金钢在Cl^-环境中具有高耐腐蚀性能相吻合。已知Zn-Al-Mg合金镀锌钢在Cl^-存在下表现出高耐腐蚀性。通过测量空气进入锈层的渗透率证实，由 Zn-Al-Mg 盐溶液制备的 Zn-Al-Mg 合金的锈是细小的片状颗粒，并且形成比 Zn-Al 合金更致密的层。较少的