Nanoindentation of coatings

A range of mechanical properties of a coating/substrate system may be obtained using indentation tests, and with the emergence of continuously recording indentation testing with nanometre penetration (often called nanoindentation) the mechanical properties of very thin coatings (<1 µm) and surface treated layers may be measured. This paper reviews the deformation mechanisms which occur and the methods for extracting mechanical properties of coatings from nanoindentation load–displacement curves and introduces the differences observed when compared with the testing of bulk materials. The importance of the relative hardness of coating and substrate on the response of the system is highlighted, and the use of energy-based models for the prediction of the performance of single and multilayered systems is discussed.