Chemical vapor deposit (CVD) diamond coating layer is expected to extend the lifetime of
mechanical parts that are used severely abrasive conditions. However, one of the most severe
problems is that the delamination between the CVD diamond coating layer and the silicon substrate
occurs frequently due to large difference in the material properties. Therefore, the nondestructive
evaluation of adhesive property of CVD diamond coating layer is needed. To address such a need,
back-scattered Rayleigh surface wave is currently applied. However, the interpretation of the acquired
signal is not easy at all. To take care of such a difficulty, we proposed the time trace angular scan
(TTAS) plot and the frequency spectrum angular scan (FSAS) plot that can make possible of the
systematic interpretation of the back-scattered signals from the diamond coating layer. In this paper,
the concept of the TTAS and FSAS plots and the experimental results presented to demonstrate the
effectiveness of the proposed approach.
