Strength and Microscopy Analysis of Surface-modified Soda-lime-silicate Glass Rods

Glass has high theoretical strength; however, microcracks on the surface of the glass greatly decrease the strength. Various methods to alleviate the effects of these cracks have been devised, including ion-exchange, mechanical abrasion, and acid etching. The goal of this experiment was to compare these methods by quantifying the strength via three-point bend testing to determine the modulus of rupture. Optical microscopy confirmed results, including the data that indicated that ion-exchange had the largest effect on strength by either widening or forcing shut cracks. Acid etching produced a moderate improvement in modulus of rupture by smoothing cracks. Finally, mechanical abrasion decreased strength but provided a more uniform strength distribution.