Corrosion Failures, Factors, and Cells

As described in the Chapter 6, corrosion damage may take various forms triggered themselves by apparently different compounding factors. The initiation and progression of corrosion processes indeed depend on the complex interaction of a multitude of factors such as 

The nature of the driving forces behind these factors has been the subject of scientific studies by many scientists in the early part of the twentieth century. In a landmark paper, Mears and Brown have summarized 18 mechanisms, listed in Table 7.1, by which differences 

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There is a vast body of information relating practically all the previously listed factors to actual field observations and subsequent analysis of failed components. These failme investigations are typically carried out in a detailed mechanistic bottom-up manner whereby a failed component would be sent to the laboratory where analytical techniques would then be used following well-established protocols. Chemical analysis, hardness testing, metallography, optical and electron microscopy, fractography, x-ray diffraction, and surface analysis are specialized tools used in such investigations. 

However, this approach alone provides little or no insight into the real causes of failure. Underlying causes of serious corrosion damage often include human factors such as lack of corrosion awareness and inadequate training and poor communication. Further underlying causes may include weak maintenance management systems, insufficient repairs due to short-term profit motives, a poor organizational safety culture, defective supplier s products, or an incorrect material selection. 

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