Fabricate an inner interface in the W sub-layer to enhance the thermal barrier of the periodic W/Al2O3 nanolaminates on glass slide

Low thermal conductivity and excellent mechanical properties are of great significance for new thermal insulation materials. Periodic nanolaminates can reduce thermal conductivity by scattering phonons at the interface between sub-layers. In this study, we developed an internal interface strategy together with the interlayer interface to jointly improve the thermal resistance and mechanical properties of the materials. Periodic W/Al2O3 and W-WOx/Al2O3 nanolaminates were fabricated on glass slide by magnetron sputtering. The thickness of each sub-layer was ∼5 nm, and the interface between the sub-layers was uniform and continuous. The internal interface in the W was produced by preparing a variety of WOx species in the sub-layer. When the O2/Ar ratio was 0.0125 in the sputtering, the W-WOx sub-layer contained four W species with different valences. The nanolaminates had a thermal resistance of 4.18 × 10−7 m2 K W−1 and nanohardness of 8.22 GPa. Comparatively, the thermal resistance and nanohardness of the W/Al2O3 nanolaminates were 1.72 × 10−7 m2 K W−1 and 7.34 GPa, respectively.