Microstructure, infrared optical properties and thermal stability of ZrB_2 and double-layer-structure Al_2O_3/ZrB_2 thin films by magnetron sputtering technique

摘要

In the present research, ZrB2 thin films and Al2O3/ZrB2 multilayer were deposited on silicon substrates using magnetron sputtering method. To investigate the thermal stability of the thin films, films were annealed at temperatures of 600 degrees C, 700 degrees C and 800 degrees C, respectively. Results from X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectrometer (FTIR) suggested that ZrB2 thin films were severely oxidized at 700 degrees C for 2 h which caused the obvious increase of infrared emissivity. In contrast, double-layer-structure Al2O3/ZrB2 thin films exhibited a low infrared emissivity of 0.16 after annealing at 750 degrees C for 2 h. Similarity, ZrB2 thin films showed a rise of infrared emissivity after annealing at 600 degrees C for 10 h. However, double-layer-structure Al2O3/ZrB2 thin films exhibited a favorable thermal stability at 600 degrees C for 30 h with a low average infrared emissivity of 0.13 in the waveband of 2-14 mu m. Compared with ZrB2 thin films, double-layer-structure Al2O3 /ZrB 2 thin films could work as low infrared emissivity layers at higher temperature for longer time for the reason that the addition of Al2O3 thin film can effectively prevent diffusion of oxygen in air during the heat treatment process.