Effect of absorbed water on the adhesion, friction, and wear of phosphate laser glass at nanoscale

Abstract

AbstractThe interaction between glass and micro‐particle in the presence of absorbed water could affect glass surface integrity, especially for the phosphate glass with a poor water resistance. In this work, using an atomic force microscope equipped with an environment chamber, the adhesion, friction and wear behaviors of phosphate laser (PL) glass were investigated by contacting with an SiO2 microsphere under vacuum, dry air, and humid air, respectively, to reveal the effect of the absorbed water on the interactions between glass and particle. Compared to vacuum and dry air, a higher adhesion force and friction coefficient as well as more material removal of PL glass were found in humid air. The capillary force caused by absorbed water greatly contributes to the high adhesion and friction in humid air. Moreover, the water meniscus forming at glass‐particle interface provides an environment for hydrolyzing P–O–P network and assists the material removal of PL glass under shear stress. Comparing the results after rubbing the SiO2 particle to those rubbed by the CeO2 particle in our previous work, in humid air, a higher shear stress and material removal rate were found in PL glass‐CeO2 pair than in the PL glass‐SiO2 pair, indicating that in the presence of absorbed water, countersurface chemistry also plays an important role in the friction and wear of PL glass at the nanoscale surface.