Electric-field assisted ion-exchange of innovative float glass

Abstract

Electric field-assisted ion exchange process was carried out on an innovative soda magnesia silicate float glass by using a specifically realized equipment which allows to change the applied voltage and the polarity and to measure the flowing current.Parameters such as surface K/Na exchange rate, potassium penetration, inter-diffusion coefficient, residual stress and case depth were measured and correlated with the processing conditions. The results revealed a high propensity of the considered glass to be chemically strengthened and a beneficial effect of the applied electric field in terms of time and temperature. For treatment carried out at 410 °C potassium penetration depth in excess to 10 μm can be achieved in less than 5 min. By alternating the polarity, both sides can be homogeneously reinforced. When the duration of each single cycle at a certain polarity is increased, the potassium penetration depth increases although cycles longer than 10 min can be detrimental.