Merachtsaki Domna, Fytianos Georgios, Papastergiadis Efthimios, Samaras Petros, Yiannoulakis Haris, Zouboulis Anastasios
Division of Chemical and Environmental Technology, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Department of Food Science and Technology, International Hellenic University, 57400 Thessaloniki, Greece.
Materials (Basel). 2020 Nov 23;13(22):5291. doi: 10.3390/ma13225291.
The biological activity occurring in urban sewerage systems usually leads to the (biogenic) corrosion of pipe infrastructure. Anti-corrosion coating technology was developed in an effort to protect sewer pipes from degradation. This study evaluates a new class of relatively low-cost magnesium hydroxide-based coatings, regarding their ability to adhere efficiently onto the concrete surface, and offer efficient corrosion protection. Six magnesium hydroxide-based coatings were prepared with the addition of two different types of cellulose, used as adhesion additives, and these were applied on concrete specimens. Pull-off measurements showed that the addition of higher amounts of cellulose could improve the coating adhesion onto the concrete surface. An accelerated sulfuric acid spraying test was used to evaluate the consumption time of the applied coatings and their efficiency in maintaining over time slightly alkaline pH values (above 8) on the coated/protected surfaces. At the end of spraying test, a mineralogical analysis of surface samples was performed, indicating that the formation of corrosion by-products (mainly gypsum) was increased when the added amount of cellulose was lower. Hardness and roughness measurements were also conducted on the concrete surfaces, revealing that the coatings helped the concrete surface to preserve its initial surface properties, in comparison to the uncoated specimens. A SEM/microstructure analysis showed that aggregates were formed (possibly consisting of Mg(OH)), affecting the reactivity of the protected surface against sulfuric acid attack.
城市污水系统中发生的生物活性通常会导致管道基础设施的（生物源）腐蚀。为了保护下水道管道不被降解，人们开发了防腐涂层技术。本研究评估了一类新型的相对低成本的氢氧化镁基涂层，考察它们有效粘附在混凝土表面的能力以及提供有效腐蚀防护的能力。制备了六种添加了两种不同类型纤维素（用作粘附添加剂）的氢氧化镁基涂层，并将它们涂覆在混凝土试件上。拉拔测量表明，添加较多量的纤维素可以提高涂层与混凝土表面的粘附力。采用加速硫酸喷雾试验来评估所涂覆涂层的消耗时间以及它们在一段时间内保持涂覆/保护表面微碱性pH值（高于8）的效率。在喷雾试验结束时，对表面样品进行了矿物学分析，结果表明当纤维素添加量较低时，腐蚀副产物（主要是石膏）的形成会增加。还对混凝土表面进行了硬度和粗糙度测量，结果表明与未涂覆的试件相比，涂层有助于混凝土表面保持其初始表面性能。扫描电子显微镜/微观结构分析表明形成了聚集体（可能由氢氧化镁组成），影响了被保护表面对硫酸侵蚀的反应性。
