Abstract

In the present study, the effect of temperature and duration of hot-dipping on structural properties, hardness, and corrosion resistance of Zn–5% Al coatings on ST13 low-carbon steel has been investigated. The samples were dipped in a molten metal bath at temperatures of 440, 480 and 520°C, during 20, 50 and 70 seconds. To investigate the microstructure and properties of samples, scanning electron microscopy, energy dispersive X-ray spectrometry, microhardness measurements, and potentiodynamic polarization corrosion tests were used. The results showed that the coating structure is an eutectic layer at 440°C, and at the interface of the substrate and the coating a thin inhibitory layer is formed that prevents the diffusion of the substrate atoms into the coating and from the molten bath into the substrate. With an increase of temperature to 480 and 520°C, with the diffusion of iron atoms of the substrate and of the molten bath, a triple metallic layer of Al–Fe–Zn forms, and the thickness of the coating increases. As the dipping time increases, the number of intermetallic particles in the coating also increases. At higher temperatures, the hardness went up from 86 to 121.73 Hv and the corrosion rate—from 7.381 to 37.53 Mpy.

Keywords

hot dip, Zn–5% Al coating, microstructure, intermetallic, corrosion

中文翻译：

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热浸镀St13 /熔融Zn-5％Al的界面研究及形成层的腐蚀行为

摘要

在本研究中，已经研究了温度和热浸时间对ST13低碳钢上Zn–5％Al涂层的结构性能，硬度和耐蚀性的影响。将样品浸入温度为440、480和520°C的熔融金属浴中20、50和70秒。为了研究样品的微观结构和性能，使用了扫描电子显微镜，能量色散X射线光谱法，显微硬度测量和电位动力学极化腐蚀试验。结果表明，涂​​层结构在440°C时为共晶层，并且在基底和涂层的界面处形成了一层薄的抑制层，可防止基底原子扩散到涂层中以及从熔池扩散到涂层中。基质。随着温度升高至480和520°C，随着基材和熔池中铁原子的扩散，形成了Al-Fe-Zn三层金属层，并且涂层的厚度也增加了。随着浸渍时间的增加，涂层中金属间化合物的数量也会增加。在更高的温度下，硬度从86 Hv上升到121.73 Hv，腐蚀速率从7.381 Mpy上升到37.53 Mpy。

关键字词

热浸，Zn–5％Al涂层，显微组织，金属间化合物，腐蚀