The calcareous deposits formed under commonly applied cathodic protection techniques on coated and uncoated carbon steel samples immersed in Guanabara Bay for 150 days, simulating ships and pipelines, were investigated. Potentials were monitored throughout the analysis, and deposits were examined by visual inspection, optical microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray diffraction. Beyond calcite, aragonite, and brucite, which are crystals commonly reported in laboratory tests or under confined space conditions, herein, also calcite‐II and calcite‐III were identified as intermediate crystalline structures. Furthermore, it was demonstrated that biological activity also plays an important role, forming calcareous tubular structures within the deposit.

中文翻译：

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根据长期原位阴极保护测试形成的钙质沉积物

研究了在常用阴极保护技术下模拟在船只和管道上浸入瓜纳巴拉湾150天的有涂层和无涂层碳钢样品上形成的钙质沉积物。在整个分析过程中对电位进行监控，并通过目测，光学显微镜，能量色散X射线光谱和X射线衍射检查沉积物。除了方解石，文石和水镁石（在实验室测试中或在有限的空间条件下通常报告的晶体）之外，方解石-II和方解石-III也被鉴定为中间晶体结构。此外，已证明生物活性也起重要作用，在沉积物中形成钙质管状结构。