Friction between scratching and cracking

We have almost all of that in our pockets. It is hard, but also soft, and thin, but also thick. We are of course talking about this gorilla glass. This tough glass has been incorporated into over a billion smartphones, but what exactly is it? How do you reduce cracks but not necessarily reduce scratches?

What is that? Studied physics and chemistry

In 2008, American company Corning introduced Gorilla Glass, a tempered glass for smartphones. The company has now released nine versions of Gorilla Glass, thus making sure for years that your smartphone screen doesn’t instantly break into a thousand pieces if you drop it. To get a good explanation of how Gorilla Glass is made so strong, we have to go back to school. It’s a challenging and technical story, but don’t worry, we won’t discuss it in great detail. We try to explain it as briefly and understandably as possible.

Corning glass is very strong because it has been hardened by a chemical process. Glass gets its hardness by immersing it in a 400-degree potassium-salt ion exchange bath. In this bathroom, the chemical elements of the glass are “replaced” by others. This changes the composition of the glass. In Gorilla Glass, for the true physics and chemistry lovers among us, Na+ (sodium) is replaced by K+ (potassium).

On the same surface, smaller sodium ions are replaced by larger potassium ions. Because potassium is larger, it takes up more space. However, because this occurs on the same surface, these ions are pressed against each other. This creates tension in the glass. Corning was able to spread this pressure from the surface over the entire glass, making the glass stronger overall.

Not just the scent of roses and sunsets

Corning’s goal is to make glass as thin and as strong as possible. As a result, it wants to meet the demand for a thinner smartphone on the one hand and ensure that this thin glass does not chip or break quickly on the other hand. crutch.

However, this sounds easier than it is, because there is a limit. You have to see it as a kind of struggle. If you make the glass more solid and thicker, it will scratch less quickly. As a result, it will break faster. To reduce the likelihood of glass breaking, you need to make it thinner and softer. However, this in turn ensures that the glass will scratch faster. In general, the higher the hardness of the glass, the faster it will crack. The smoother the glass, the more sensitive it is to scratches. Corning should always think about this and find a balance.

catastrophic sand

You often see well-known videos on the Internet in which Gorilla Glass is tested. You often see that Corning has succeeded in making strong glass. Keys, for example, no longer cause scratches, and glass often survives drops from one and a half meters.

However, there are still things to watch out for that Corning hasn’t found a good solution for yet. There is one detail that causes a lot of scratches on our beautiful smartphones: the sand. Sand is mainly composed of silicon dioxide. A compound used, among other things, in the manufacture of glass. This makes sand much stronger than, for example, minerals. So small and sharp grains of sand can easily cause scratches. So be careful with sand in your pockets after visiting the beautiful beach.

next step

The next step in the Smartphone Screen is sapphire glass. A synthetic type of glass that is virtually scratch-free, unless you intend to scratch it with diamonds, and is used in Omega watches, among other things. However, the disadvantage of sapphire glass is that it takes a long time to produce and therefore is expensive to manufacture.
We have to wait until the technology allows this process to take less time and thus become applicable on a larger scale.

Do you suffer from scratches or cracks in your screen? And how did that happen? Let us know in the comments below this article!