Nondestructive Characterization of Corrosion Protective Coatings on Aluminum Alloy Substrates

This paper describes the initial phase of the development of a nondestructive, multisensor approach for detecting, quantifying and monitoring degradation of organic coatings applied ot aluminum surfaces. Descriptions of the purposes and chemical composition of layered coatings used on aircraft structures are provided. The discussion then concentrates on ultrasonic thickness measurements. One is the well-established pulse/echo scanning acoustic microscopy and, as a proposed alternative, contiuous acoustic waves measurements with a probe in contact to the sample. Advantages and disadvantages of the two methods and their potential as in field applications are discussed.