One of the key factors in Apple’s success in the gadget market over recent years is its ability to iterate a design and feature set. While the original iPhone was a game changer, it did have its faults. But importantly, the new iPhone models that followed fixed those issues while continuing to develop the device and the platform.A new patent granted to Apple this week could hint at yet another issue the company has solved. The iPhone, iPod touch, and iPad all look great when you first buy them, but after months of use the cases will no doubt have a few scratches on them. It’s the kind of thing we all put down to general wear and tear, and it is pretty much unavoidable.The patent Apple has secured is for adding a nitride layer to devices. This layer is transparent and invisible to the eye, but it manages to stop the underlying materials from getting scratched. If Apple coats the next generation of its iDevices in this nitrate layer it could mean an end to scratched cases, or at the very least they stay scratch free for longer.The awarded patent is entitled “Nitriding stainless steel for consumer products” and the abstract makes it clear this is a relatively cheap solution for protecting a device. It’s also thin enough that not only does the underlying materials color come through, but so does its texture.Apple will be able to continue using stainless steel as a case material, and has detailed a salt bath nitrate process for applying this scratch-resistant layer to it. The process takes up to 90 minutes at 580 degrees Celsius to apply a layer up to 30 microns thick, after which it can be polished to leave a smooth finish. The resulting protective layer has a Vickers hardness test value of 1,000+.Read more at AppleInsiderMatthew’s OpinionThe patent was filed in April of last year, so this nitride layer may already be in use on some Apple products. If it isn’t, then it surely will be on the next generation of devices to cut down on the potential for scratches. There’s little reason not to use it as the result is invisible and incredibly thin.Apple isn’t shy of experimenting with new materials in a bid to make products better. There’s no better example of this than the experimentation with, and exclusive licensing of Liquidmetal. It’s an amorphous metal alloy that’s almost impossible to bend by hand and is already being considered for use in fuel cells.