Studies Of AlO_x/SiO_x Coatings Deposited By Magnetron Sputtering

Ever since in the 80s last century Japan has developed a transparent high-barrier flexible packaging materials by evaporating SiOx (1.5≤x≤1.7) film on the surfaces of the plastic film, the new technology has been the world's attention. In the recent years, the packaging materials of AlOx (1≤x≤1.5) films have also been brought forth consecutively in Japan and Germany. AlOx film and SiOx film not only have the same gas barrier property as the aluminum film by evaporating, but also have a good microwave permeability, high transparency, heat resistance, rupture resistance, folding resistance, corrosion resistance, easy complex machining etc., and shall be particularly suitable for the packaging materials of the food, medicine and other things which can be microwave sterilized. In particular, it easier to be recycled than plastic composite materials, and does not pollute the environment, which draws common concern of society in the packaging waste problems. As a mainstream technology preparing the packaging materials, AlOx film and SiOx film, magnetron sputtering is favored because of its high-speed, low-temperature characteristics. Using argon ion sputtering technology, SiOx thin films were physical vapor deposited (PVD) by RF magnetron sputtering and AlOx thin films were plasma-enhanced chemical vapor deposited (PECVD) by DC reactive magnetron sputtering on the flexible plastic substrate (PET).For the PVD method, by changing the three process parameters, RF power, argon gas flow rate and coating time, prepare different SiOx thin films. For the PECVD method, by changing the four process parameters, DC current, argon gas flow rate, oxygen flow rate and coating time, prepare different AlOx thin films. Determine the process parameters of high-barrier films by the stable experimental study.By Fourier transform infrared spectroscopy (FTIR), detected the molecular structure of thin film surface composition, analyzed of the film surface composition; By MOCON oxygen permeability testing instrument and water vapor permeability testing instrument tested the barrier properties of films, drew the maps of the relationship between barrier properties and process parameters, optimized the process parameters; Using scanning electron microscopy (SEM) to characterize the surface morphology of films, analyzed the relationship between barrier. properties and the films'surface uniformity; By electronic tensile testing machine, tested mechanical properties of thin films, depicted the curves of the relationship between the mechanical properties and process parameters; Finally by microwave heating tests verified the microwave permeability of the films.At last, the optimal parameters of SiOx thin films prepared by PVD are background pressure 7.5×10-3Pa, RF power 1500w, argon gas pressure 0.23 Pa, coating time 30min, and under this condition SiOx films' oxygen barrier property has grew 69 times, water vapor barrier property has increased 30 times, yield intensity 4.4 times, elastic model 3.3 times. The optimal parameters of AlOx thin film prepared by PECVD are background pressure 7.5×10-3Pa, DC current 2A, argon gas flow rate 105sccm, oxygen flow rate 9sccm, coating time 30min, and under this condition AlOx films' oxygen barrier property has boomed 60 times, water vapor barrier property has ascent 11 times, yield intensity3.4 times, elastic model 5.8 times.