Hot-dip Zn55Al-coated steel samples have been exposed for up to 6 years at 11 different weathering sites, including marine, marine-industrial, acid-rain and dry atmospheres. From the mass loss measurements, Zn55Al metallic coating showed globally long-term good corrosion resistance in all weathering conditions compared with hot-dip Zn-0.2Al-coated steel (Z). Yet, weaker performance was observed on Zn55Al in high SO₂ polluted atmosphere, particularly when combined with seawater aerosols. This is explained by a more acidic surface condition linked to high SO₂. Although the extent of corrosion in this phase was different at the different sites, the final corrosion products formed after 6 years were rather similar at all sites. This consists of hydrous aluminium sulphate or hydrous aluminium hydroxy sulphate and, probably also a smaller amount of sulphate-containing zinc corrosion products or Al/Zn products.

中文翻译：

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Zn55Al涂层钢的长期大气腐蚀速率

热浸 Zn55Al 涂层钢样品已在 11 个不同风化地点暴露长达 6 年，包括海洋、海洋工业、酸雨和干燥大气。从质量损失测量来看，与热浸镀 Zn-0.2Al 涂层钢 (Z) 相比，Zn55Al 金属涂层在所有气候条件下均表现出长期良好的耐腐蚀性。_{然而，在高SO 2}污染的大气中，尤其是与海水气溶胶结合时， Zn55Al 的性能较差。_{这可以通过与高 SO 2}相关的更酸性的表面条件来解释。尽管不同地点这一阶段的腐蚀程度不同，但6年后最终形成的腐蚀产物在所有地点都相当相似。它由水合硫酸铝或水合羟基硫酸铝以及可能还有少量的含硫酸盐的锌腐蚀产物或铝/锌产物组成。