Dual-spectrum bands compatible Ti-Si-O film prepared by magnetron co-sputtering

Military stealth places higher demands on dual-band electromagnetic wave response in the infrared and microwave bands, and an outer layer with both low infrared emissivity and high microwave transmittance is required for multi-layer compatible stealth materials. In this work, a series of Ti-Si-O films were prepared by magnetron co-sputtering and annealing as the outer layer. The infrared emissivity and microwave transmittance of as-deposited films increase gradually with the decrease of Ti content. After annealing, the microwave transmittance increases obviously due to the occurrence of Ti-O reaction, and only the film with a Ti/Si ratio of ∼7/1 can maintain a low infrared emissivity. In the optimized film, microwave-transparent TiO grains are generated while original electrically conductive amorphous region still exists and surrounds around TiO, which makes it have both a low average infrared emissivity of 0.32 in infrared band from 2.5 to 25 μm and a high average transmittance of 88.5% in microwave band (2.42–3.66 cm).