The corrosion behaviors of high oxide ion conductors using solid oxide membrane (SOM) electrolysis were investigated in practical operating conditions (current load or molten CaF₂‐NaF‐CaO eutectic salt). In previous researches, yttria‐stabilized zirconia (YSZ), which is widely used in SOM electrolysis due to its good mechanical properties and ionic conductivity at high temperature, has several problems including phase transition due to yttrium ion dissolution, which results in decreased current efficiency and severe fracture of SOM tube. Thus, we introduced oxide ion conductors with a higher ionic conductivity than that of YSZ to exploit its excellent current efficiency and long‐term stability. In this study, we investigated the phase stability of Sr‐ and Mg‐doped lanthanum gallate (LSGM), Sc‐doped zirconia (ScSZ) and Gd‐doped ceria (GDC) using the structural analysis methods. Phase transition of LSGM and ScSZ easily occurred than that of GDC. GDC showed fairly tolerable stability; the molten salt ions were found only 10 μm deep on the surface, and the ions hardly penetrated the interior of bulk. However, LSGM (~40 μm) and ScSZ (~100 μm) showed a deep cation ion infiltration depth from the surface and severe surface corrosion was observed on the surface of LSGM and ScSZ.

中文翻译：

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用于高温直接电化学还原金属氧化物的氧化物离子导体的腐蚀行为

在实际操作条件下（电流负载或熔融的CaF ₂）研究了使用固体氧化物膜（SOM）电解的高氧化物离子导体的腐蚀行为-NaF-CaO共晶盐）。在先前的研究中，由于氧化钇稳定的氧化锆（YSZ）由于其良好的机械性能和高温下的离子电导率而被广泛用于SOM电解中，但它存在一些问题，包括由于钇离子溶解引起的相变，从而导致电流效率降低。以及SOM管严重断裂。因此，我们推出了具有比YSZ更高的离子电导率的氧化物离子导体，以利用其出色的电流效率和长期稳定性。在这项研究中，我们使用结构分析方法研究了掺Sr和Mg的镓酸镧（LSGM），掺Sc的氧化锆（ScSZ）和掺Gd的二氧化铈（GDC）的相稳定性。LSGM和ScSZ的相变比GDC容易发生。GDC表现出相当宽容的稳定性；在表面仅10μm的深处发现了熔融盐离子，并且离子几乎没有渗透到内部。然而，LSGM（〜40μm）和ScSZ（〜100μm）表现出从表面的深阳离子渗透深度，并且在LSGM和ScSZ的表面观察到严重的表面腐蚀。