Influence of Acid Frosting on the Microstructure Characteristics and Mechanical Strength of Eroded Soda-Lime-Silica Glasses by Sandstorm

Most glass products such as cars windshields, solar panels protecting glass and windowpanes are exposed to unavoidable sandblasting effects especially in areas prone to sandstorms. This sand impingement results into micro cracks and surface flaws which altered the structure and strength of the exposed glasses thereby lowering their service life. In this regard, attempt was made in this research to investigate the influence of acid frosting technique as a means of surface modification on the microstructure characteristics and mechanical strength of eroded soda-lime-silica glass. Several glass samples measuring 80x60 mm were initially prepared and exposed to sand impingement from a sandblasting machine with an air flow speed of 15m/s and an impact angle of 90°. The sandblasted glass samples (S_control) were later immersed in Hydrofluoric Acid (HF) for acid frosting procedure at dipping period of 5, 10, 15 and 20 minutes respectively. Microstructure characteristics were examined using scanning electron microscopy while flexural strength test was conducted to assess the mechanical strength of the sample glasses. The results showed that mechanical strength of the etched-sandblasted samples (S+E series) improve significantly as the dipping period increases compared with sandblasted glasses. In term of microstructure, homogenously distributed micro-cracks and numerous flaws were observed on the eroded glass samples while for the   S+E series, the stress riser effect of these micro-cracks are well eliminated which accounts for the strength improvement.