A resonant frequency technique developed to determine the elastic constants and the internal friction of isotropic and anisotropic bulk materials from 300 K to 1500 K was extended to the determination of Young’s moduli of thin coatings. This paper presents the measurement technique and the associated calculations. Results for very thin films (approximately 2 mu m) of SiC and NiTi obtained by dynamic ion mixing (DIM) are presented. This technique, which involves ion sputtering evaporation combined with a high energy ion implantation, gives well adherent and homogeneous coatings. It is shown that such films have very low Young’s modulus compared with the classically prepared crystalline materials. It is assumed that these low values have their origin in the amorphous structure of the DIM films.