The role of computed tomography in understanding inhibitor release from coatings

The mechanism of inhibitor release from coatings containing corrosion inhibitors is important in many industries from aerospace to infrastructure. Models of release often assume Fickian diffusion and treat the polymer matrix as a medium through which this occurs. However, the details of structures within coatings including those based on polymer structures, inorganic particles (such as fillers) and inhibitors is poorly explored. X-ray and backscattered electron computed tomography (X-ray CT and BSE-CT respectively) based on a variety of techniques are revealing the rich variety of structures that exist with paint coatings and shedding new light on transport mechanisms within these coatings. X-ray CT can be based on a range of different measurements including the most commonly used probe of X-ray absorption and to a lesser extent backscattered electron contrast. This paper provides an overview of the use of some of these types of techniques in investigating paint structure for pipeline coatings.