Carbonate stability plays a crucial role in clarifying the evolution and protection of the naturally formed corrosion scales on the steel surface in the application of geothermal production. In this paper, the stability of the corrosion scales from both micro and atomic level are studied via a combination of electrochemistry, surface analysis and first-principle calculation. The chemical and physical characterisation of various iron–calcium mixed carbonates are experimentally analysed and results are compared with the first-principle calculation. In the presence of Ca²⁺, the preferential loss of Ca during the dissolution experiments was observed, the interactions within the crystal weaken where Ca²⁺ co-precipitation, confirmed by a faster degradation rate for Ca_0.51Fe_0.49CO₃ than FeCO₃. This work reveals the degradation and protection performance of the naturally formed carbonate layers and provides insights into understanding the corrosion product stability and chemical breakdown of the corrosion scales.

碳酸盐的稳定性在澄清地热生产应用中对钢表面自然形成的腐蚀垢的演变和保护起着至关重要的作用。本文结合电化学，表面分析和第一性原理计算，从微观和原子层面研究了腐蚀尺度的稳定性。实验分析了各种铁钙混合碳酸盐的化学和物理特征，并将结果与​​第一性原理计算进行了比较。在存在Ca ²⁺的情况下，观察到了溶解实验中Ca的优先损失，晶体内部的相互作用减弱了，而Ca ²⁺共沉淀时，Ca _0.51的更快降解速率证实了该相互作用Fe _0.49 CO ₃比FeCO ₃贵。这项工作揭示了天然形成的碳酸盐层的降解和保护性能，并为了解腐蚀产物的稳定性和腐蚀垢的化学分解提供了见识。