Ion Exchange of Soda‐Lime Glass with Univalent Cations

Abstract

Fhdeld‐assisted and ordinary diffusion ion exchange of K+, Rb+hd Cs+, and Ag+ from nitrate salts with Na+ in soda‐lime glass tubes were investigated between 700 and 735 K by application of various currents between 0 and 20.0 mA. An analysis of the field‐assisted process with both a forward and a reverse field allowed calculation of the conductivity of the exchanged layer from the change of potential difference with time. Good agreement with experiment was found in both directions but anomalously high conductivities were observed in the Rb and Cs layers. Photoelastic measurements on rings sliced from the ion‐exchanged tubes were used to calculate the residual stress arising from the ion exchange with the different cations. These results showed that other factors in addition to the ion size influence the magnitude of residual stress after exchange. The voltage‐current relation during field‐assisted ion exchange, along with the Nernst‐Einstein equation, permitted calculation of the self‐discussion coefficient of the exchanged cation in the exchanged layer. The self‐diffusion coefficient was also estimated by applying the Nernst‐Planck equation to results from unassisted ion‐exchange experiments.

Trends in Effective Diffusion Coefficients for Ion-Exchange Strengthening of Soda-Lime-Silicate Glasses

“…It has been shown before that the obtained values are in reasonable agreement with other published data (Pask and Parmelee, 1943;Shaisha and Cooper, 1981;Gonella et al, 1998;Liu and Pun, 2004;Karlsson et al, 2010bKarlsson et al, , 2012. In a practical consideration, the effective diffusion coefficient represents the efficiency of the ion-exchange reaction, in other words, the rate of the ion exchange.…”

On Weak Convergence of Semimartingales to Stochastically Continuous Processes With Independent and Conditionally Independent Increments

“…Refractive-index profiles were generated from measured n,E data using the WIG3 method (Chiang 1985). Shaisha andCooper 1981, Honkanen andTervonen 1988) that information concerning the relative mobilities of the sodium and silver ions can be obtained by analysing the change in the electrical conductivity of the glass during diffusion of the silver. This has previously been achieved by monitoring the current passing through the sample as a function of time during diffusion with a constant applied potential (Viljanen andLeppihalme 1981, Honkanen andTervonen 1988) or by monitoring the voltage developed across the sample as a function of time during a constant-current process (Shaisha and Cooper 1981).…”

“…Shaisha andCooper 1981, Honkanen andTervonen 1988) that information concerning the relative mobilities of the sodium and silver ions can be obtained by analysing the change in the electrical conductivity of the glass during diffusion of the silver. This has previously been achieved by monitoring the current passing through the sample as a function of time during diffusion with a constant applied potential (Viljanen andLeppihalme 1981, Honkanen andTervonen 1988) or by monitoring the voltage developed across the sample as a function of time during a constant-current process (Shaisha and Cooper 1981). While, in principle, these appear to be straightforward measurements, it is necessary to eliminate secondary effects when using solid (as opposed to molten salt (Shaisha and Cooper 1981)) back contacts.…”

“…This has previously been achieved by monitoring the current passing through the sample as a function of time during diffusion with a constant applied potential (Viljanen andLeppihalme 1981, Honkanen andTervonen 1988) or by monitoring the voltage developed across the sample as a function of time during a constant-current process (Shaisha and Cooper 1981). While, in principle, these appear to be straightforward measurements, it is necessary to eliminate secondary effects when using solid (as opposed to molten salt (Shaisha and Cooper 1981)) back contacts. We have observed that the motion of the sodium ions towards the back contact sets up a potential difference, its value being dependent upon the material used as the back contact (silver or graphite) as well as upon temperature, current density and time.…”

Mechanical Properties of Ag+/Na+ Ion-exchanged Aluminosilicate Glasses

“…2 and 3 are considered to be the expansion of Al-O-Si network of mother glass due to the introduction of large foreign ions, and the following slight decreases during annealing are considered to be the shrink of Al-O-Si network due to certain atomic adjustment. Previously, Shaisha et al 20 reported that Ag Na ion exchange induces a relatively small compressive stress on the glass surface compared with other alkali ion-pairs because of the small difference of the ionic radius between Ag and Na . This difference of the ionic radius would increase the volume of mother glass.…”