Define "coating thickness" in ultrasonic testing terms.

In ultrasonic testing (UT), "coating thickness" refers to the measurement of the thickness of protective or decorative coatings applied to a substrate material. This measurement is crucial because coatings can affect the propagation of ultrasonic sound waves, thus impacting the ability to accurately assess the underlying material. Understanding the thickness of these coatings is essential for ensuring the integrity and quality of the substrate, as excessive coating may lead to increased sound attenuation and reduced sensitivity during testing.

Coatings can vary widely in their composition and purpose, ranging from corrosion-resistant layers to aesthetic finishes. When conducting ultrasonic testing, accurate knowledge of the coating thickness enables technicians to calibrate their equipment appropriately and interpret the results of the testing more effectively.