Indentation of Silicate‐Glass Films on Al 2 O 3 Substrates

The deformation of thin layers of glass on crystalline materials has been examined using newly developed experimental methods for nanomechanical testing. Continuous films of anorthite (CaAl 2 Si 2 O 8 ) were deposited onto Al 2 O 3 surfaces by pulsed‐laser deposition. Mechanical properties such as Young's modulus and hardness were probed with a high‐resolution depth‐sensing indentation instrument. Nanomechanical testing, combined with AFM in situ imaging of the deformed regions, allowed force‐displacement measurements and imaging of the same regions of the specimen before and immediately after indentation. This new technique eliminates any uncertainty in locating the indentation after unloading. Emphasis has been placed on examining how the Al 2 O 3 substrate crystallographic orientation will affect mechanical composite response of silicate‐glass film/Al 2 O 3 system.