Using a reciprocating ball-on-flat tribometer, the friction and wear behaviours of phosphate laser (PL) glass were investigated in dry air and liquid water to reveal the effect of tribo-corrosion on the reciprocating scratch behaviours of PL glass. In this regard, material removal and (sub) surface cracking of PL glass were studied by comparing the absence/presence of water under reciprocating scratch conditions. It was found that regardless of applied load conditions, material removal volume in water was higher than the test in dray air, suggesting that the tribo-corrosion (shear stress-assisted hydrolysis) accelerated the material removal of PL glass in water. In contrast, surface and subsurface cracking at the contact region of PL glass in water were weaker than the test in dry air, and stress-corrosion and tribo-corrosion alone cannot explain the suppressed cracking in water. It was suggested that liquid water acted as a lubricant during friction, which reduced the shear stress on glass substrate to weaken glass cracking. The results provide new insights into the scratch behaviour of glass materials, which would be useful in understanding the contact damage mechanism of glass materials in the presence of water.
