Search Results for coating failures

Coatings, such as those applied to ships, must be resistant to abrasion, in the case of cargo hold coatings, and cyclic changes of chemicals and tank cleaning, in the case of tank linings. Failures and defects can manifest themselves at various times in the life of a coating. To determine the cause and mechanism of coating failure, all possible contributory factors must be evaluated together with a detailed history from the time of application to the time the failure was first noted. Many coating failures require further evaluation and analysis to be carried out by a qualified chemist or coating specialist, often using specialized laboratory equipment. The article presents examples of coating failures and defects, together with descriptions, probable causes, and suggested preventative measures.

This article discusses the standard conduct of coating failure investigation. As each failure is different, a specific coating failure may require increased emphasis on a given step, or additional work and/or steps may be required. This article covers the following topics: obtaining and analyzing background information, preliminary determination of site conditions, inspection equipment requirements, coating failure site investigation, sampling techniques, sample chain of custody, coordination with the coatings laboratory, report preparation, and sample retention.

This article provides an overview of common analytical tools used as part of the process of providing practical information regarding the causes of a coating problem or failure. The common analytical tools include Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy-energy dispersive X-ray spectroscopy, chromatography, and electrochemical impedance spectroscopy. Test cabinets and standard test environments for laboratory analysis are reviewed. The article describes non-standard simulation testing and case studies of simulated environments for coating failure analysis.

Polymeric floor coatings refer to flooring materials composed of multicomponent thermoset resins formulated with various fillers and pigments that are installed in situ, usually over concrete substrates. Polymeric flooring systems, specified for all industrial and commercial environments, use a variety of polymer chemistries and are constructed in a variety of methods and designs. This article provides a description of the service conditions for the polymeric flooring systems. It provides information on polymeric flooring systems, including thin-film coatings, self-leveling systems, membrane systems, broadcast systems, troweled systems, and terrazzo. The article also focuses on properties, applications, testing, and factors and requirements to be considered during the installation of polymeric floor coatings. It concludes with a discussion about coating failures, including bonding, cracking, chemical attack, and moisture that affect the polymeric floor coatings on concrete.

This article provides information on thermal spray coating features, which combine to determine the properties of a coating. These include the lamellar or layered splat structure, entrapped unmelted or resolidified particles, pores, oxide inclusions, grains, phases, cracks, and bond interfaces. The article describes the sources of porosity and the factors that control the final coating porosity levels. The article also lists the materials most suitable for thermal spraying processes.

A major cause of failure in components subjected to rolling or rolling/sliding contacts is contact fatigue. This article focuses on the rolling contact fatigue (RCF) performance and failure modes of overlay coatings such as those deposited by physical vapor deposition, chemical vapor deposition, and thermal spraying (TS). It provides a background to RCF in bearing steels in order to develop an understanding of failure modes in overlay coatings. The article describes the underpinning failure mechanisms of TiN and diamond-like carbon coatings. It presents an insight into the design considerations of coating-substrate material properties, coating thickness, and coating processes to combat RCF failure in TS coatings.