Apple has been granted ownership of an invention related to scratch-proof coatings on stainless steel devices, using a nitride layer to potentially make iPhones, iPads and Macs more durable.

The U.S. Patent and Trademark Office this week granted ownership of the invention "Nitriding Stainless Steel for Consumer Electronic Products" to Apple. Known as U.S. Patent No. 7896981, it describes a cost-effective system that uses a nitride coating to prevent scratches and blemishes on the metal surface of a mobile device.

Adding a layer of nitride atop a stainless steel exterior would protect a device from damage. But the choice of material would maintain the look and feel of stainless steel, as nitride allows the color of the metal to show through.

Nitride is not to be confused with titanium nitride, a ceramic material that is also used as a coating on metal. Unlike nitride, which is clear, titanium nitride has a metallic gold color that conceals the look of the metal beneath it.

Apple's invention notes that stainless steel, while scratch-prone, is an ideal material to craft electronic devices. Stainless steel is preferable because it is not magnetic, and it is less likely to inhibit wireless technology like a cell phone signal, Wi-Fi or Bluetooth.

The addition of nitride could give Apple the best of both worlds: the advantages of stainless steel would remain, while a nitride coating would address the chief concern of durability.




Apple first filed for the invention in April of 2010.



Apple Insider