Surface acoustic wave spectroscopy versus nanoindentation: Potentials and limits for coating characterization

Measuring mechanical film properties is essential for understanding and designing coating systems as well for controlling quality in coating manufacturing. Since more than two decades, two methods for determining Young’s modulus and other mechanical properties of thin films are widely used: The instrumented indentation technique (nanoindentation) and the laser-induced surface acoustic wave spectroscopy (LiSAWS). Due to their different physical principles, both methods address different fields of application but also complement each other. This presentation gives an overview for typical applications, strengths and limits for both methods from practical points of view like precision, requirements for sample material, preparation and test setup, additional results, standardization, and measuring time.
Several examples for the application of both methods are discussed:
• Hard protective coatings (deposited by PVD and thermal spraying) measured with both techniques
• Films with less than 15 nm thickness
• Effect of texture, microstructure and defects on measured properties