Abstract:

Chemical strengthening of glass by ion exchange has become very attractive for thin display glass because of superior scratch resistance and durability which is achieved by such surface treatment. The compositional profile is governed by diffusion of ions within a concentration gradient, imposed to the solid glass by immersion in a molten salt. The depth of ion exchange is governed by time and temperature of treatment and limited by the mechanical stress which builds up in the strengthened glass. In order to overcome such limitation an electrical field gradient can be applied along with the chemical gradient, e.g., by a DC electrical field using electrodes. In our work the transport of ions is investigated in a superimposed AC field, using microwave radiation. The electrical field distribution and the chemical as well as electrical gradients are simulated to compare the different driving forces and their superposition. The calculated compositional gradient is compared with experimental results for different new glass types, which were developed for optimized production of future optical precision pressed components.