Effects of Sliding Velocity on the Friction and Wear Behaviors of Phosphate Laser Glass

The effects of sliding velocity on the friction and wear behaviors of phosphate laser glass were investigated in two loads using a reciprocating sliding tribometer in humid air. The experimental results show that the friction coefficient of phosphate laser glass decreased with increase in sliding velocity, and the decrease was more obvious in low load condition. Under low velocity sliding, the wear debris of phosphate laser glass was found to accumulate mainly at the end of the wear track. But under high velocity sliding, the localized temperature rise of contacting asperities caused the adhesive wear, as a result, the wear debris adhered to the center of the wear track more easily. The adhesive wear was more severe in high load condition due to the higher localized temperature rise at frictional interface. With increase in sliding velocity, the wear volume of phosphate laser glass decreased. This is attributed to the inadequate adsorbed water film at the interface at higher sliding velocity due to the short residence time of the water molecules at the contact interface, as well as the higher temperature rise. As a result, the tribochemical wear induced by water is weakened under high velocity. Compared to high load condition, the effect of sliding velocity on the material removal of phosphate glass was more obvious in low load condition. The relatively lower temperature rise under low load wear was more conducive to the stable formation of the interface water film, therefore, the tribochemical reaction played an important role in the material removal of phosphate glass in low load condition.