Study on the stability of nano-polycrystalline Ag films in thermal and humid environment.

This study systematically investigates the degradation behavior of nanopolycrystalline silver films (npAgF) in a thermal and humid environment, focusing on analyzing the impact of specific environmental factors on their performance evolution, especially the formation pathways of degradation products and their impact on optical properties. NpAgF samples were prepared by ion-assisted deposition and electron beam evaporation, and a six-month environmental test was conducted under controlled temperature and humidity. During the process, changes in the chemical state, surface morphology, reflectivity, and residual stress of the film were continuously monitored. The results show that the adsorption of moisture and corrosive gases on the silver film changes its interfacial properties, promotes the migration of Ag ions, and leads to the formation and growth of degradation products. By combining the characterization results of the degradation products with the fitting analysis of the optical constants, the evolution path of the silver film during degradation can be better simulated. This work reveals the degradation mechanism of npAgF under thermal and humid conditions from an experimental perspective and provides a basis for improving their long-term stability in the atmospheric environment.