Design,Preparation Of Al/Cr₂o₃ Composite Films And Its Visible And Infrared Performances

In view of the demand for multi-band compatible camouflage material under the military targets,Al/Cr₂O₃ film is used as the multi-band compatible camouflage material.The structure of the film system of the multi-band compatible camouflage material was designed,deposited and studied in this research,and the multi-band compatible camouflage material was prepared with good properties.The TFCalc software was used to simulate the visible spectra of the composite film with different thickness of Cr2O3 film.Based on the theoretical calculation,the composite film with particular color can be prepared.Al film has a good infrared low emissivity characteristic,and Cr₂O₃ film has a good visible light camouflage characteristic,so the Al/Cr₂O₃ film has a good property of multi-band compatible camouflage.The Al film,Cr₂O₃ film and Al/Cr₂O₃ film were prepared with the magnetron sputtering.The influence of the sputtering temperature on the surface morphology of Al film was studied,it shows that with the increase of the sputtering temperature,the surface roughness of Al film increased gradually.The influence of preparatio n processing,such as sputtering temperature,sputtering time,sputtering power and sputtering pressure,on the phase structure,element composition,surface and section morphology was studied mainly.It shows that when the sputtering temperature is500℃,Cr₂O₃ film with good crystal state can be deposited;stoichiometric Cr₂O₃ film can be prepared by Cr₂O₃ target,and there is no other chromium oxide;with the increase of sputtering temperature and sputtering power,the roughness of Cr₂O₃ film has an increasing trend,when the sputtering pressure is 4 mTorr,the sputtering rate is the highest,it is about 70 nm/h.After optimizing the technique of preparation,Al/Cr₂O₃ film with good multi-band compatible camouflage property was deposited on Al substrate a nd Si substrate,the influence on the multi-band compatible camouflage property of substrate type,the crystal state and thickness of Cr₂O₃ film was studied,and the thickness of Cr₂O₃ film was changed to optimize the multi-band compatible camouflage property.Whether the Cr₂O₃ film is crystal or amorphous,when the thickness of Cr₂O₃ film is low,the color of composite film changes with the increase of Cr₂O₃ film thickness,when the thickness of Cr₂O₃ film is over 700 nm,the color tends to be stable.In the wavelength of 3⁵μm,when the Cr₂O₃ film thickness changes from 200 nm to 300 nm,the infrared emissivity of composite film suddenly increases,then with the increase of Cr₂O₃ film thickness,the infrared emissivity has a periodic change with first decrease and then increase;in the wavelength of 8¹4μm,with the increase of Cr₂O₃ film thickness,the infrared emissivity of composite film tends to increase gradually.In the Al/Cr₂O₃ composite film,when the thickness of c-Cr₂O₃ film is more than700 nm,the color of the composite film is green;when the thickness ofα-Cr₂O₃ film is between 100 nm and 300 nm,the color of the composite film is green.At the same time,the composite film has a suitable low infrared emissivity,and it has large application potential in multi-band compatible camouflage technology.