Name a non-destructive test used to evaluate coating integrity on turbine blades and describe what it detects.

• A. Radiographic testing detects changes in coating color.
• B. Visual inspection detects coating thickness.
• C. Ultrasonic thickness testing detects coating thickness, delamination, or corrosion under coatings.
• D. Magnetic particle testing detects delamination under coatings.

Answer: (C)