The hot-dip Al and AlSi coatings are synthesized on Mo substrate at different temperatures. The microstructure and low-temperature oxidation behavior both of the coatings are investigated. The results indicate that hot-dip Al coating is mainly made up of an AlMo outer layer and an AlMo interface layer, while the hot-dip AlSi coating is consists of a Mo(Si, Al) inner layer and AlSi alloy outer layer containing Mo(Si, Al) grains. After exposed at 600 °C for 40 h, a large number of cracks initiate on surface and inside of the hot-dip Al coating, its mass gain per unit area () reach to 10.32 mg/cm, and the RSa (average surface roughness) and Sdr (surface area growth rate) values increase from 0.216 μm and 6.602% before oxidation to 1.214 μm and 35.297%, respectively. During the oxidation process, the structure of the hot-dip AlSi coating is preserved intact, and almost no cracks are observed in the coating. After oxidized at 600 °C for 150 h, the Δm of hot-dip AlSi coating is only 1.56 mg/cm, and the RSa and Sdr values increase from 0.458 μm and 7.083% to 1.509 μm and 43.586%, respectively. Besides, the oxidation rate constant () of hot-dip Al and AlSi coatings are 7.42 × 10 and 4.47 × 10 mg·cm·s, respectively, and the latter is only 6.17 × 10 times than that of the former. The excellent oxidation resistance of hot-dip AlSi coating is attributed to its small grain size, stable and dense coating structure, and complex oxide layer composition.

中文翻译：

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Mo基体热浸镀Al和Al[sbnd]Si涂层在600℃静态空气中的低温氧化行为及机理


在不同温度下在Mo基体上合成热浸Al和AlSi涂层。研究了两种涂层的微观结构和低温氧化行为。结果表明，热浸镀Al涂层主要由AlMo外层和AlMo界面层组成，而热浸镀AlSi镀层则由Mo(Si, Al)内层和含Mo的AlSi合金外层组成。 (Si、Al)晶粒。 600℃暴露40h后，热浸镀铝镀层表面和内部均产生大量裂纹，单位面积质量增益()达到10.32mg/cm，RSa(平均表面粗糙度) ）和Sdr（表面积增长率）值分别从氧化前的0.216μm和6.602%增加到1.214μm和35.297%。在氧化过程中，热浸AlSi涂层的结构保持完整，涂层中几乎没有观察到裂纹。 600℃氧化150h后，热浸AlSi涂层的Δm仅为1.56mg/cm，RSa和Sdr值分别从0.458μm和7.083%增加到1.509μm和43.586%。此外，热浸Al和AlSi镀层的氧化速率常数()分别为7.42×10和4.47×10 mg·cm·s，后者仅为前者的6.17×10倍。热浸AlSi镀层优异的抗氧化性能归因于其晶粒细小、镀层结构稳定致密、氧化层成分复杂。