Corning Responds to Note 7 and Gorilla Glass 5 Scratch Tests
If you have been on the Internet lately, you may have heard of JerryRigsEverything and his durability tests. Bordering on the lines of torture testing, Jerry’s videos do give us a comparison scale of how various devices react to situations that they could face, commonly with regards to scratching and bending.
One of Jerry’s videos, that of the Samsung Galaxy Note 7, had a very interesting observation regarding scratching and Gorilla Glass 5.
The point that piques our interest is how the new Gorilla Glass 5 that makes an appearance on the Note 7 seemingly scratches with a pick of hardness 3, while Jerry mentions that most phones work till around the 5 – 6 hardness picks. The takeaway from the video was that the Gorilla Glass 5 may have traded off its scratch resistance for increase in its shatter resistance.
When the information sheet for the Gorilla Glass 5 went live, we did have a conversation in our internal chats about how Corning did not do any significant advertisement in relation to the improvements in scratch resistance. The sheet was a bit cryptic and used “similar” too often when referring to scratch performance.
The folks over at Android Authority reached out to Corning to get some answers. Corning’s VP of Technology, Jaymon Ameen and Corning’s Business Technical Director for Gorilla Glass, John Kazansky start off by saying:
The test that was conducted in the video is not a bonafide industry test. It’s using Mohs hardness picks but it’s in an uncontrolled manner. We also don’t know a whole lot about what loads the person has used. Whether those loads are changing as he goes through the testing.
Further, they mention that all glass falls between a Mohs hardness of 5-6, so a pick of 3 cannot scratch glass with at least standard hardness.
So, what is it that we see in the video?
The hardness pick that was used in the video was a 3, that’s considerably softer than the glass material. Oftentimes when you have a softer material like that, and depending on what kind of loads you have used, you tend to see material transfer on the test substrate.
Material transfer on the test substrate is not necessarily a scratch but it can appear to the untrained eye as a pretty visible scratch. We don’t know whether or not that is what is being seen in the video. Certainly in the testing we’ve done internally, we don’t see that issue at all with similar picks on the Mohs hardness scale.
They further go on to reaffirm that what we see in the video is the pick transferring onto the glass. They mention that the combination of both, the material hardness and the pressure that gives rise to such occurrences.
When asked if the Gorilla Glass 5 was at least as scratch resistant as the Gorilla Glass 4, the duo tried to work around against an immediately definite answer (yes/no).
The glass is designed to improve the drop performance and not necessarily designed to improve the scratch performance. When we consider all hardness tests, GG5 is actually harder than GG4. Based on our testing, for scratch performance as well as the hardness testing we do that’s widely used in the industry, we believe that GG5 should be performing similarly to GG4.
“Similar” again, so the question was asked again, to which they replied:
Yes, that is correct.
So if the glass had material residue from the pick on top of it, why was it not removed when attempts were made to wipe it off? The spokespersons answered to Android Authority:
It can be very, very difficult to remove metallic material transfer from glass. It is very atypical to see in a field return when we look at scratches of glass, that kind of characteristic, but purely visual, perceived damage that is actually a material on top of the surface.
Talking about the relation between shock absorbency and scratch resistance:
“There might be a misconception in the thought process [about shock absorbency and flexibility]. What we’ve done with GG5 is designed to maximize the damage resistance of the glass itself. What that does is provide additional resistance to the flaws that get introduced during drop events and provide additional retained strength during those drop events so you can have higher drop performance.
That’s slightly different than thinking about it from a shock absorbance or flexibility perspective. It’s actually more about preventing flaws in glass, which is a brittle material, not about making a soft, shock absorbing material.”
Whether the Samsung Galaxy Note 7 can be as easily scratched as demoed or not, this is something that we look forward to finding out in our own review. Stay tuned!
What are your thoughts on the scratch-gate of Gorilla Glass 5? Let us know in the comments below!