Hodgkiess T
Department of Mechanical Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
Water Sci Technol. 2004;49(2):121-8.
The processes of corrosion and scale deposition in natural and process waters are often linked and this paper considers a number of instances of interactions between the two phenomena. In some circumstances a scale layer (e.g. calcium carbonate) can be advantageously utilised as a corrosion-protection coating on components and this feature has been exploited for many decades in the conditioning of water to induce spontaneous precipitation of a scale layer upon the surfaces of engineering equipment. The electrochemical mechanisms associated with some corrosion and corrosion-control processes can promote alkaline-scale deposition directly upon component surfaces. This is a feature that can be exploited in the operation of cathodic protection (CP) of structures and components submerged in certain types of water (e.g. seawater). Similar phenomena can occur during bi-metallic corrosion and a case study, involving carbon steel/stainless steel couples in seawater, is presented. Additional complexities pertain during cyclic loading of submerged reinforced concrete members in which scale deposition may reduce the severity of fatigue stresses but can be associated with severe corrosion damage to embedded reinforcing steel. Also considered are scale-control/corrosion interactions in thermal desalination plant and an indirect consequence of the scale-control strategy on vapourside corrosion is discussed.
天然水和工业用水中的腐蚀和水垢沉积过程通常相互关联，本文探讨了这两种现象之间相互作用的一些实例。在某些情况下，水垢层（如碳酸钙）可有利地用作部件上的防腐涂层，几十年来，这一特性已被用于水的处理，以促使在工程设备表面自发形成水垢层。与某些腐蚀和腐蚀控制过程相关的电化学机制可直接促使碱性水垢沉积在部件表面。这是在浸没于某些类型水（如海水）中的结构和部件的阴极保护（CP）操作中可利用的一个特性。双金属腐蚀过程中也会出现类似现象，并给出了一个涉及海水中碳钢/不锈钢偶对的案例研究。浸没的钢筋混凝土构件在循环加载过程中会出现额外的复杂情况，水垢沉积可能会降低疲劳应力的严重程度，但可能会对埋入的钢筋造成严重腐蚀损坏。本文还考虑了热法海水淡化厂中的水垢控制/腐蚀相互作用，并讨论了水垢控制策略对蒸汽侧腐蚀的间接影响。
