The isothermal phase transformation behavior of thermally grown oxide scale of FeO on high-purity Fe was investigated under conditions of low oxygen potential. The phase transformation comprised three reactions, namely Fe 3 O 4 precipitation, magnetite seam formation, and the eutectoid decomposition. The nucleation rate of Fe 3 O 4 precipitation decreased with decreasing oxygen potential, whereas the incubation period for the eutectoid decomposition became longer. In contrast, magnetite seam formation was independent of the oxygen potential. The overall phase transformation was found to reach completion faster in an atmosphere with a lower oxygen potential. The effect of the oxygen potential on the phase transformation of FeO scale was rationalized by the different degree of supersaturation for Fe 3 O 4 precipitation, which plays a crucial role in the eutectoid reaction.

中文翻译：

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低氧势下在高纯 Fe 上形成的热生长 FeO 的相变

研究了在低氧势条件下热生长的 FeO 氧化皮在高纯 Fe 上的等温相变行为。相变包括三个反应，即Fe 3 O 4 沉淀、磁铁矿层形成和共析分解。Fe 3 O 4 沉淀的成核率随着氧势的降低而降低，而共析分解的潜伏期变长。相比之下，磁铁矿层的形成与氧势无关。发现整体相变在具有较低氧势的气氛中更快地完成。通过不同程度的Fe 3 O 4 沉淀过饱和度，可以合理化氧势对FeO 氧化皮相变的影响，