Abstract
A thin-film coating generally is a single or multiple layered thin film deposited on a component to extend its life and performance. Two techniques will be discussed in this lecture: acoustic microscopy and laser-based ultrasonics. The V(z) measurement by line-focus acoustic microscopy provides a very suitable technique for the quantitative nondestructive determination of thin-film elastic constants and the bond quality at interfaces. After some brief comments on acoustic microscopy, the modeling of ultrasound propagation in multilayered configurations is summarized. The modeling results are used in a measurement model for the V(z) effect, which can be used to select a frequency range suitable for a particular configuration. In combination with measurements, the model is subsequently employed to determine elastic constants and interface stiffnesses. Experimental results are presented for single, multilayered, isotropic and anisotropic films. The effect of imperfect interfaces on strength considerations is also discussed. Next we briefy discuss the generation of ultrasound in thin film/substrate configurations by laser irradiation of the film's surface. A simplified theory for laser-generated ultrasound is presented and some experimental results are shown.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 8-13 |
| Number of pages | 6 |
| Journal | Key Engineering Materials |
| Volume | 270-273 |
| Issue number | I |
| DOIs | |
| State | Published - 2004 |
| Event | Proceedings of the 11th Asian Pacific Conference on Nondestructive Testing - Jeju Island, Korea, Republic of Duration: Nov 3 2003 → Nov 7 2003 |
Keywords
- Acoustic Microscopy
- Laser-Based Ultrasonics
- Material Properties
- Measurement Models
- Thin Films
ASJC Scopus subject areas
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering