Elastic constant determinations of SiC/NiP composite coating by surface acoustic wave and nano-indentation

Elastic constant determinations of coatings deposited on a substrate are performed using a surface acoustic wave technique, and the ultrasonically determined elastic constants are compared with mechanically determined ones using a nano-indentation technique in order to examine the present ultrasonic technique for its validity. The experimental results for a NiP coating have shown that the Young's moduli determined ultrasonically and mechanically coincide with each other Within an error range of 2%. This demonstrates that the present ultrasonic technique has been successfully applied to the elastic constant determination of such coating. Based on this result, SiC/NiP composite coating (SiC particle reinforced NiP coating) of Wpm thickness was examined. The result using the surface acoustic wave indicated a 32% increase in Young's modulus due to the randomly dispersed SiC particles. The validity of this result is also discussed in comparison with mechanically and theoretically estimated results.