Environmental effects on initiation and propagation of surface defects on silicate glasses: scratch and fracture toughness study

Effects of humidity and counter-surface on tribochemical wear of soda-lime-silica glass

“…Thus, it was believed the wear of glass in humid environments occurs through a mechanochemical process rather than a purely mechanical one. Besides, the wear resistance of soda-lime glass increased as environmental humidity increased, which was not observed for other glasses such as fused silica, borosilicate, and aluminosilicate glasses [18,19]. These results indicated that the water reactivity inside the wear track of the soda-lime glass substrate being rubbed with silica or borosilicate glass balls is quite different from other glasses.…”

“…However, this stress corrosion process alone cannot explain the humidity dependence of wear for glass materials upon tangential or interfacial sliding [19]. Our previous studies found that borosilicate and aluminosilicate glasses show an increase in wear as the humidity of the environment increases, while soda-lime-silica glasses exhibit a decrease in wear as the humidity approaches to the saturation point [17][18][19]. This peculiar humidity dependence of soda-lime glass is not fully understood yet, but it is speculated that the presence of leachable sodium ions and the chemical reactivity of the water species occupying the sodium-leached sites must play some roles [17].…”

“…This reaction is called stress corrosion and is responsible for the enhanced propagation rate of cracks in most silicate glasses in humid conditions [47,48]. However, this stress corrosion process alone cannot explain the humidity dependence of wear for glass materials upon tangential or interfacial sliding [19]. Our previous studies found that borosilicate and aluminosilicate glasses show an increase in wear as the humidity of the environment increases, while soda-lime-silica glasses exhibit a decrease in wear as the humidity approaches to the saturation point [17][18][19].…”

“…These reports suggest that the chemical reactivity of counter-surfaces play important roles in the mechanochemical wear of sliding interfaces. Previous investigations on environmental effects reported that the friction and wear behaviors of multicomponent silicate glass substrates tested with silica and borosilicate glass balls vary drastically with humidity [17][18][19]. In dry conditions, glass substrates were easily scratched creating a very rough and deep wear track.…”

Cross-section Morphology of the Scratch-Induced Cracks in Soda-Lime-Silica Glass

“…In addition, variation of the composition dependence of SR is much smaller than that of CR. Recently, in focusing the degradation behavior of cover glass in mobile electronic devices, scratch behavior of surface-strengthened glasses were reported (Gross, 2012;Schneider et al, 2012;Surdyka et al, 2014). High load scratch behavior as a model of grinding process was also reported recently (Gu and Yao, 2011;Bandyopadhyay et al, 2012).…”