Acoustic microscopy has been used as a non-destructive analytical tool for characterising various coating/substrate systems. A novel high-frequency instrument especially developed for Materials Science engineers is presented, and its technical and theoretical specifications are described. In the acoustic signature mode (quantitative mode), local elastic moduli are extracted. The numerical results are compared to those obtained by depth-sensing indentation. In the imaging mode (qualitative mode), this technique allows without etching a clear distinction of the surface Brain structure from the stress gradients at grain boundaries and from the mechanical anisotropy of differently oriented grains. Moreover, tomographic imaging of subsurface flaws is shown. Hidden scratch-induced cracks are revealed by comparison with standard metallographic microscope observations.