Enhanced tribological properties of barium boroaluminosilicate glass by thermal poling

Mechanical and tribological properties of barium boroaluminosilicate glass (commercial AF45® glass) treated with a thermal poling process employing 4 kV bias at 600 °C were studied. Compared to the pristine AF45 glass, the anode-side surface of the thermally poled glass has lower modifier ion concentrations and lower reduced modulus and hardness, while the cathode-side surface has increased modifier ion concentrations and shows an increase in reduced modulus and hardness. Both pristine and anode-side surfaces become more susceptible to wear as relative humidity (RH) of the surrounding environment increases from 20% to 90%; in contrast, the cathode-side surface exhibits a remarkable wear resistance at 90% RH. It was speculated that the increased wear resistance of the cathode-side surface at high RH conditions might be due to the accumulation of leachable modifier ions (especially sodium ions) in the subsurface region. These results may serve as a design rule to control the mechanochemical wear damage of optical glasses and optimize the tribological design of functional and engineering glasses in humid conditions.