Ion-exchange and the Effect of Processing on Properties of Ultra-thin Aluminosilicate Glass

Pure KNO₃ was selected as the molten salt, while one-step and two-step methods were used for ion-exchange of ultra-thin aluminosilicate glass for applications in cell phone displays. The distribution of ion concentration in the ion-exchanged glass was characterized by using EDS. The effects of ion-exchange process on depth of the compressive stress layer (DOL), surface compressive stress (CS), Vickers hardness, density, transmittance and chemical stability of the glass were systematically studied. It is found that the increase in ion-exchange temperature and time as favorable to the DOL, CS and Vickers hardness. However, when the temperature exceeded 400 ℃ and the time exceeded 2 h, the CS and Vickers hardness decreased sharply due to the stress relaxation effect. With the two-step method, the ion concentration gradient was raised, which further improved the CS and Vickers hardness. The ion-exchange process increased density and chemical stability of the glass without reducing the transmittance. These findings are useful for the strengthening of ultra-thin glass for cell phone display applications.