Preparation and performance of ZrAlN anti-reflective coatings for low-emissivity glasses

Hard and optically selective films are useful for low-emissivity applications and the surface layer of optical elements. In this paper, ZrAlN films were prepared by RF magnetron sputtering on glass substrates at room temperature under different power and gas flow rate. Microstructure, optical properties, chemical compositions and tribological properties of the coatings were investigated and the results indicate that the ZrAlN coatings, prepared with a nitrogen flow rate of 6 sccm, target power of 110 W for both Al and Zr, can give an excellent visible light transmittance that allows 90% of light in the range of 400-600 nm to transfer through the glass and films. Especially, the Transmittance of the ZrAlN is 93.4% at the wavelength of 550 nm which is higher than glass. The emissivity of ZrAlN coating is about 0.74, much lower than bare glass. The coatings maintain the optical properties even under salt spray test for 336 h. the results proved that the ZrAlN films are excellent anti-reflective coatings with superior mechanical property and high corrosion resistance, it can be used in low-emissivity glasses and some other optical components.