The mechanical performance of optically tuned ceramic nanomultilayers

• Published in: Materials & design 2023-07, Vol.231, p.112014, Article 112014
• Main Authors: White, Danielle E., Appleget, Chelsea D., Rossi, Edoardo, Sebastiani, Marco, Hodge, Andrea M.
• Format: Article
• Language: English
• Subjects: Ceramic; Coatings; Mechanical; Multifunctional; Nanomultilayer; Optical
• ISSN: 0264-1275
• DOI: 10.1016/j.matdes.2023.112014

[Display omitted] •Aperiodic and bilayer configurations of AlN/SiO2, TiO2/SiO2, and AlN/Al2O3 nanomultilayers are tested using microtensile, nanoindentation, and pillar splitting techniques.•Volume fraction, interfaces, and individual constituent properties are tunable parameters that affect the optical and mechanical behavior of the nanomultilayers.•Crystalline/amorphous AlN/Al2O3 nanomultilayers demonstrate equivalent tensile strengths and hardness values in the aperiodic and bilayer configurations.•Crystalline/amorphous AlN/SiO2 nanomultilayers present a higher fracture toughness and transmittance in the aperiodic layer configuration than in the bilayers.•The complexity of aperiodic layer thicknesses should be further explored to understand how they affect overall mechanical behavior. Multifunctional optical nanomultilayers (NMs) are needed for a wide array of applications, ranging from optical windows to electronic screens. Since the individual material constituents in optical coatings are often selected only for their desirable optical properties, mechanical characterization of the optical nanomultilayers is typically limited. Here, AlN/SiO2, TiO2/SiO2, and AlN/Al2O3 nanomultilayers synthesized in non-optimized and optimized optical performance layer configurations are tested using microtensile, nanoindentation, and pillar splitting techniques to highlight the effects of optical optimization on mechanical performance. Trends within each type of test and across all deformation modes reveal that layer thickness, volume fraction, and interfacial crystallinity can be viewed as controlling features for optical and mechanical performance, although their correlation may vary. It was observed that both configurations of the AlN/Al2O3 NMs exhibit the highest mechanical performance across all three testing techniques with an average experimental transmittance of 93.8% for the optimized layer configuration. Overall, the results from this expanded view of mechanical properties in ceramic optical nanomultilayers suggest the possibility of tuning film characteristics for joint optimization of opto-mechanical nanomultilayered coatings.