The three new iPhone models unveiled by Apple last Wednesday each carry an IP68 rating allowing them to be submerged in water as deep as nearly 5-feet for as long as 30 minutes. In addition, Apple says that the glass used on the devices is the most durable glass ever used on a smartphone. That might be enough to satisfy iPhone owners for now, but Apple isn't standing still. A patent application filed with the USPTO in March, 2017 reveals that the company is working on an abrasion-resistant finish that can protect the device from dents and scratches.
The patent application mentions a hard outer layer with an intermediate layer in between a metal substrate and the outside coating. The latter could be made of a ceramic material or a hard carbon-based material with all the hardness of a diamond. The outside layer would have a thickness between .5 micrometers and about 3 micrometers, and would be harder than the intermediate layer. This "in-between layer" would measure between 8 micrometers and 30 micrometers.
The name of the patent application is "Abrasion-Resistant Surface Finishes On Metal Enclosures On Metal Enclosures" and according to the document, the coatings provide improved resistance to abrasion and denting. The patent application adds that "Coatings that provide improved resistance to abrasion and denting are described."
Check out some images from the patent application by clicking on the slideshow below.