Modulation periods and ratios induced changes of microstructure and mechanical properties of AlN/ZrB2 multilayered coatings

AlN/ZrB₂ multilayered coatings were synthesized in a magnetron sputtering system. The extensive measurements were employed to investigate the influence of different nanoscale modulation periods and modulation ratios on microstructure and mechanical properties of the coatings. Analysis of X-ray diffraction, profiler and nanoindention indicated that multilayered coatings possessed much higher hardness and elastic modulus than monolithic AlN and ZrB₂ coatings. At the substrate negative bias of −80 V, maximum hardness (34.1 GPa) and elastic modulus (469.8 GPa) were obtained in the multilayer with Λ = 30 nm and t_AlN:t_ZrB2 = 1:3. This hardest multilayer showed a marked polycrystalline structure with the strong mixture of ZrB₂ (001), ZrB₂ (100), ZrB₂ (101), AlN (100) textures.