CoatingsPro Magazine

MAR 2016

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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Page 62 of 84

62 MARCH 2016 COATINGSPROMAG.COM Never Again F i gu re 1 . A m ag n i f i ed v i ew o f t h e outer tube from the unit is presented. A relatively rough texture is evident in the view. The Case of the Flaked Nickel Plating By Craig J. Schroeder, P.E., Senior Engineer, Metallurg y for Element Materials Technolog y W hen a coating fails, it can adversely afect the performance of the part it was intended to protect and result in corrosion damage, blistering, or possibly the initiation of fatigue cracking from a pit. Such failures can not only harm the reputa- tion of the manufacturer, but they can lead to litigation, recalls, and delays in delivery due to quality concerns. Understanding why a coating failed is critical to preventing similar failures from reoccurring. In the study of a failure, the analyst must consider a broad range of possibilities for the failure. A lthough some failures can be attributed to a single primary cause, it is common for multiple secondary factors to contrib- ute, too. Te failure analyst must evaluate all of the evidence available to prepare a hypothesis about all of the causes of failure. Te most common type of coating failure that is studied is disbonding due to poor adhesion. Disbonding typically occurs due to insufcient cleaning of the substrate or due to contaminants present between the substrate and the coating or between various layers of the coating system. Since cleaning and coating processes can be complicated — involving many steps and exposure to many types of solvents, acids, baths, etc. — identifcation of the contaminant can be critical in determining where in the process that contamination occurred. Research Results A well-equipped materials failure inves- tigation laboratory should have most of the tools to efectively analyze a compo- nent that has experienced these types of failures. Tese tools may include a low-power stereomicroscope, metallo- graphic equipment, spectrometer, and Photos courtesy of Element Materials Technolog y The investigation can be thought of as a forensic puzzle. The more pieces of the puzzle that are in place, the more conclusive the investigation will become.

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