Thermal stability and optical properties of low emissivity multilayer coatings for energy-saving applications

Abstract In this study, the deposition and characteristics of Si- and Ti-series multilayer coatings with respective glass/Si3N4/NiCr/Ag/NiCr/Si3N4 and glass/TiO2/ZnSnO3/ZnO/Ag/NiCrOx/ZnSnO3/Si3N4 structures were investigated. Experimental analyses were performed, and the optical performance and thermal stability of the coatings were assessed. The as-deposited Si- and the Ti-series samples exhibited optimal shading coefficient of 0.49 and 0.57, respectively. Thermal annealing in air was performed to analyze the thermal stability and oxidation resistance of the samples. The Si- and Ti-series samples prevented the failure of low-emissivity properties at 700 and 600 °C, respectively. In addition to high transparency, the Si-series samples exhibited improved low-emissivity properties, reduced light pollution, and superior thermal stability compared to the Ti-series samples. The use of Si3N4 and NiCr layers effectively prevented the oxidation and cracking of the Ag layer upon heat treatment. This study presents the characteristics of Si- and Ti-series samples for energy-saving building applications.