Abstract
iological materials in nature are often functionally optimized through evolution. As a classic case, abalone nacre possesses exceptional mechanical properties to prevent predatory. Consisting of 95 wt.% CaCO3 with only 5 wt.% organics contents, nacre has formed a unique “brick-and-mortar” microstructure which significantly enhanced its toughness. Inspired by this intricate design, multilayer coatings of materials with low/high elastic moduli including Al/Al2O3, Zr/ZrN, PMMA/Al2O3 and many others were synthesized by a combination of reactive RF sputtering and pulsed laser deposition. Structural and elemental analyses via AFM, SEM, TEM, XRD and FE-EPMA showed microstructural features with layer thickness ratios similar to that of abalone nacre (0.3-0.5 μm inorganics / 10-50 nm organics). Nano-indentation and nano-scratch tests were performed to evaluate the mechanical properties of the multilayer coatings, where the enhancements and toughening mechanisms of various systems were compared and discussed. This research is funded by the National Science Council, Taiwan (NSC-100-2218-E-007-016-MY3).