Synthesis of nanoscale CNx/TiAlN multilayered coatings by ion-beam-assisted deposition.

CN_x/TiAlN multilayered coatings with different nanoscale modulation periods and ratio of CN_x within each period were prepared by ion-beam-assisted deposition at room temperature. Auger electron spectroscopy (AES), x-ray diffraction (XRD), and nanoindenter and a profiler were used to characterize the microstructure and mechanical properties of the coatings. The low-angle XRD pattern and AES indicated a well-defined multilayered structure of the coating. Although monolithic CN_x and TiAlN coatings formed amorphous and nanocrystalline structures, respectively, the CN_x/TiAlN multilayers exhibited coherent epitaxial growth due to the mutual growth-promoting effect at small CN_x layer thickness (<0.6 nm). At modulation period Λ=2.83 nm and CN_x thickness of 10% within each period, the multilayers exhibited strong TiAlN (111) and weak AlN (111) textures and showed the highest hardness (32 GPa), elastic modulus (409 GPa), and critical fracture load (65.7 mN). [ABSTRACT FROM AUTHOR]