Q: My smartphone’s screen is made of Gorilla Glass. How is it different from other glass? -Jennifer Williams, Vancouver
A: As wireless phone screens have grown from tiny postage stamp–sized screens to the 4.5-inch (or bigger) screens of today’s top-end smartphones, they have one obvious Achilles’ heel: the display glass itself.
Traditional glass – such as window glass, also known as “soda-lime” glass – is thin and prone to cracking. Plus, it scratches easily.
Solution: Make smartphone glass thicker, right? Wrong. As glass gets thicker, its clarity decreases and it makes your smartphone larger and heavier. And with smartphones, thin is in.
Enter Gorilla Glass – glass that’s strong, scratch-resistant and ultrathin. How so? It’s a closely guarded secret held by its manufacturer and patent-holder, Corning. What we do know is that once the top-secret glass mixture is prepared, it’s then melted into a molten glass slurry before being pulled off into sheets and subjected to some serious science (see below). In scientific terms, the atomic properties of sodium and potassium are exploited to somehow change the glass’s chemical composition, creating a strong, scratch-resistent surface.
Here is how Gorilla Glass is made in the factory:
- The raw materials are melted together and then poured into a V-shaped trough.
- Glass sheets take form once the molten material begins to harden, and a robotic arm grabs these super-thin glass sheets.
- The sheets take a dip into a molten potassium salt bath at 400 degrees Celsius, hot enough to break the ionic bonds of the sodium in the glass sheet, but not so hot as to melt the sheet.
- Smaller sodium ions break free and are replaced with larger potassium ions. In short, jamming the larger potassium ions into the space previously occupied by the sodium ions in the 400-degree hot tub results in an ionic transfer that results in glass that’s super strong. Thank god for science!