Mechanical properties and photostability of fast-growing wood deposited with nano-Al₂O₃/ZnO composite films

Fast-growing wood generally has drawbacks such as soft texture, low strength, and poor photostability, which greatly limits its use value and application scope. In this article, nano-Al2O3/ZnO modified wood was prepared by magnetron sputtering with fast-growing poplar as the substrate. The results showed that when Al2O3 and composite films were deposited on fast-growing wood, their load-displacement curves were significantly shifted to the left, meaning that the deformation resistance of wood was enhanced. The maximum pressure depth of nano-Al2O3/ZnO/wood was 246.3 nm, a decrease of 80.1% from CTRL wood. The average elastic modulus was 4.683 GPa, an increase of 20.48 times; the average hardness was 0.731 GPa, an increase of 28.41 times. After 222 h ultraviolet irradiation, total color difference values (Delta E-& lowast;) of nano-ZnO/wood, nano-Al2O3/ZnO/wood, and nano-ZnO/Al2O3/wood were 4.31, 4.73, and 5.25, respectively, which were more than 70% lower than that of the CTRL wood (19.76). Continuous and uniform nanofilms were observed on the surface, and the highest weight percentage of Al and Zn elements reached 9.38% and 60.21% respectively. It was concluded that the nano-Al2O3/ZnO/wood prepared by magnetron sputtering resulted in good Young's modulus, hardness, and photostability, achieving multi-function improvement of fast-growing wood.