If you use a touchscreen phone or tablet computer, there’s a good chance the surface you’re furiously poking and prodding is a product called Gorilla Glass. A predecessor to the glass was made by Corning in the 1960s, nearly 50 years before the company resuscitated and tweaked the technology for “damage resistant” displays for consumer electronics. Here’s a look at the science behind the glass.
1. Salt Bath
Specially made glass is placed in a bath of potassium nitrate. In a process called ion exchange, smaller sodium ions at the surface of the glass get swapped with larger potassium ions in the salt bath. (The degree of ion exchange falls off further from the surface.)
2. Compression layer
The larger ions help create a “compression layer” that acts as an armor against scratches and other damage: Glass is strong under compression (it breaks under tension), so for, say, a crack to spread, it needs to penetrate Gorilla Glass’s enhanced compression layer.
3. Grace under pressure
The finished product, Corning says, is two times stronger than traditional glass at half the thickness. The glass is used by 20 major brands, and Corning (GLW) has started selling it to television makers. One potential market: people who accidentally throw Wii handsets at TV screens.