Apple has just received the patent for scratch-proof coatings, that will be applied to stainless steel devices, possibly making future iPhones, iPads and Macs more durable. The technology uses a nitride layer and it’s a cost effective system that will protect metal surfaces from scratches and blemishes.

This protective layer won’t change the look and feel of stainless steel, as nitride allows the metal color to be seen through. The patent also mentions details about how to apply the nitride coating to devices, which includes using a salt bath nitride process. There’s also a method that involves a nitrogen salt bath with an average temperature of 580 degrees Celsius.

Chemistry aside, this invention was first filed for in April 2010 and it was discovered in October 2010 by Appleinsider. What about the rumor saying that the next iPhone will use liquid metal as its main material?