Strengthening glass with ion exchange
Corning® Gorilla® Glass redefined the toughness and durability of consumer electronics. Thanks to this cover glass, which has been featured on more than 5 billion devices, consumers have thinner, sleeker devices with exceptional damage resistance to the scratches and bumps of everyday use. What's more, Corning keeps making Gorilla Glass more damage resistant and proving its use in a growing number of applications – from elevators to vehicles.
Gorilla Glass gets its damage resistance from Corning's ion-exchange process for strengthening glass. But, how does that work?
First – it is essential to understand why glass cracks or shatters. Glass will break from flaws on its surface. These flaws will propagate when there is tension on the glass. The ion-exchange process for strengthening glass essentially puts the surface of the glass in a compressive state helping to resist the tension that occurs during damaging events.
In the process for strengthening glass, Corning first uses its trademark fusion process to manufacture a pristine glass sheet. This glass then soaks in a molten salt solution. Potassium ions in the solution migrate into the glass surface, replacing the smaller sodium ions within the structure of the glass. These larger potassium ions create a compressive stress layer that forms a tough surface.