Electron microscopy and energy dispersion analysis are used to reveal structural features of an oxide film in the region of white deposit areas that are visually detected on the surface of cylindrical ingots of 6000 series aluminum alloy after homogenizing annealing. It is shown that a loose film of aluminum and magnesium oxides with an anomalously high Mg content (up to 45 at.%) and micropores are typical for these areas. Diffusion flow of magnesium towards the surface during homogenizing annealing gives rise to its chemical potential gradient occurring as a result of oxidation processes occurring during annealing. Reasons are determined for the occurrence of white deposit areas connected with formation at an ingot surface of mineral salt oxides and organic compounds from dried liquid used for cooling during ingot semi-continuous casting.

中文翻译：

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6000系铝合金圆柱锭表面氧化膜结构

用电镜和能量色散分析揭示了均质退火后的6000系铝合金圆柱锭表面白色沉积区区域氧化膜的结构特征。结果表明，具有异常高 Mg 含量（高达 45 at.%）和微孔的铝和镁氧化物的松散膜是这些区域的典型特征。在均质化退火过程中，镁向表面的扩散流动会导致其化学势梯度，这是退火过程中发生的氧化过程的结果。确定了出现白色沉积区的原因与在锭半连续铸造过程中用于冷却的干燥液体在锭表面形成矿物盐氧化物和有机化合物有关。