Hardware

What is Gorilla Glass and why is it so strong?

Gorilla Glass
Disappointingly, the glass isn't actually designed or made by gorillas

As product names go, Corning’s Gorilla Glass is a doozy. It immediately conjures up images of a glass so incredibly strong that even the world’s largest primate can’t smash it. We’re not sure that Corning has ever handed over a Huawei smartphone or Samsung laptop to an angry silverback, but Gorilla Glass still lives up to its name for the most part: it’s durable but also thin and ideal for touchscreens. So what actually makes Gorilla Glass much tougher than normal glass?

Gorilla Glass: How is it made?

Like Willy Wonka and his Everlasting Gobstopper, Gorilla Glass is a product of Corning’s unique manufacturing technique (although there’s now a close equivalent in the form of Asahi Glass’ Dragontail). Needless to say, the process is complicated – and very hot. In fact, it’s so precise that no human hands ever touch the glass during its manufacture, reducing the risk of imperfections.

Fusion

  • First, the raw materials are mixed together, melted down and then conditioned.
  • This molten glass gloop (that’s the technical term) is then fed into a big trough called an isopipe until it overflows and glass falls evenly over both sides – like an extremely deadly waterfall.
  • The mixture remixes at the bottom and is stretched out into a sheet that’s mere microns thin (we told you it was a fiddly process).

Ion-exchange process

So far, so simple? Well, the next stage involves “stuffing” large ions into the glass’ surface to create “a state of compression” – a process that gives Gorilla Glass its trademark toughness.

  • The glass is plunged into a bath of hot salt at a balm temperature of 400˚C. Ouch.
  • Small sodium ions then leave the glass and are replaced with large potassium ions from the salt.
  • When the glass cools, these larger ions squeeze together, producing a so-called “layer of compressive stress” on the surface of the glass. The ingredients Corning uses in Gorilla Glass mean that these potassium ions sink far into the surface, making it even tougher.

Gorilla Glass: Just how strong is it?

Before it goes into handsets, Corning puts its glass through a wide variety of stress tests. One of these involves dropping a heavy steel ball from a height of nearly two metres onto the glass, while another sees the glass bent 70mm into a U shape.

In the real world, Corning promises that you can drop a Gorilla Glass 5-coated phone from a height of 1.6m onto tarmac without incurring any damage. To fully test this claim, I diligently dropped my Huawei phone from above my head… actually, no I didn’t – I’ll take Corning’s word for it, rather than having to splash out for a replacement. If you’re braver than me, give it a go, but we wouldn’t recommend it.

Gorilla Glass: Is it on my device?

If you own a recent Android phone, it’s highly likely that you spend a good proportion of your life staring through Gorilla Glass – the press releases and videos proudly proclaim that it’s been used on more than 4.5 billion devices. To put that number in perspective, that’s more than the population of Asia.

If you’re still not sure, the Corning website includes a list of all of the smartphone, tablet, laptop and wearable brands that make use of Gorilla Glass.

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About the author

Max Figgett

Max has written for numerous websites and magazines over the years. Whether it’s about ancient hardware or software secrets, no Big Tech Question is too obscure for him to tackle.

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