Preparation And Characterization Of WalN/Ag/WalN Films

Environmental pollution and energy crisis are two problems of sustainable development in the 21 th century.With the process of accelerated urbanization,building energy consumption will sustained growth,using the eco-friendly and energy-efficient low-emissivity films has becoming hot-debated issues in recent years.The development of new low-emissivity films with high transmittance in the visible light region,high reflectivity in the infrared region and long service life from the structural and componential improvements are the key points.West countries have begun to study low-emissivity films from the last century 70 s,now has been widely used.However,China started late,and technology is undeveloped,the optical properties of current commercial low-emissivity films is poor,and durability is also urgent to improve.Therefore,using new materials,new technology to obtain more superior properties of low-emissivity films,exploring new films structure to further improve the optical prpertise and corsion resitance of low-emissivity films is great significant accelerating the application of low-emissivity films in China.The object of the dissertation is set to partly solve the limitations in the present low-emissivity films research area,for which WAlN/Ag/WAlN sandwiching structure low-emissivity(Low-E)films were prepared by radio frequency reactive magnetron sputtering(RF-MS)on glass substrates.Firstly,the visible light transmittance and infrared reflectance of WAlN thin films were investigated.The effect of magnetron sputtering parameters on the visible light transmittance of WAlN dielectric layer was studied by single factor variable method.The optimum process of WAlN thin film was obtained by laboratory conditions parameter.The results show that the WAlN films prepared with the best parameters have a transmittance of 95% in the visible range and about 30.1% of the infrared reflectivity,which can enhance the transmittance of films.SEM surface morphology analysis shows that the film is uniform and dense,less surface defects,which can give Ag film better protection.Therefore,WAlN films have the performance requirements of low-emissvity films dielectric layers.Next,the magnetron sputtering preparation process of the functional layer Ag film is explored.The effect of magnetron sputtering process parameters on the photoelectric properties of Ag film was studied,and a single layer Ag film with excellent photoelectric properties was prepared.The results show that the single-layer Ag film with 12 nm thickness is the best,the surface resistance is 7.5?/?,the maximum visible light transmittance is 84.2% at 500 nm,the visible light transmittance at the most sensitive 550 nm is 83.3%.Finally,the influence of the thickness of WAlN dielectric layer on the visible light transmittance and corrosion resistance of the composite films was investigated,and the WAlN/Ag/WAlN composite low-emissivity films with excellent comprehensive performance was prepared.The results show that the WAlN film with 45 nm thick can improve the visible light transmittance of the composite film and improve the symmetry of the transmittance curve of the composite films,and ensure the visual effect.At the same time,the soaking experiment showed that 45 nm thick WAlN film could provide better protective effect to Ag film.The visible light transmittance before and after corrosion was less than 4%,which was in accordance with the national standard.The use of nitride WAlN as the outer dielectric layer of low radiation film solves the oxidation problem of the Ag layer of the functional layer during the preparation of the oxide dielectric layer.The visible light transmittance of WAlN(45nm)/Ag(12nm)/WAlN(45nm)single silver low radiation composite films prepared at this time is as high as 83.98% at the wavelength of 550 nm,the infrared reflectance is 96.5%,the standard low radiation rate is 0.043,and the visible light transmittance is less than 4% before and after soaking.It is a kind of low-emissivity films with high visible light transmittance,high infrared reflectance and long service life.