If a new patent application from Apple is any indication, the company is getting obsessive about making sure that future products are highly scratch-resistant.
The U.S. Patent and Trademark Office published Apple's application this week titled "Nitriding Stainless Steel for Consumer Electronic Products," outlining methods for depositing a very thin layer (just over 15 microns thick) of nitride to stainless steel to provide scratch and impact resistance. Nitride coatings are unique in that they allow the natural feel and look of the stainless steel to show through, while creating a tough scratch-proof surface.
In the patent filing, Apple notes that stainless steel is a highly desirable material for consumer electronics since it is non-magnetic and doesn't hinder Bluetooth, Wi-Fi, and cellular signals as much as other metals. However, as some iPhone 4 owners have noticed, the material is relatively easy to scratch.
Apple also entered into an agreement with Liquidmetal Technologies earlier in 2010 to explore using the company's amorphous metal technology in future scratch-proof Apple products. Liquidmetal materials are twice as strong as titanium, but as easy as plastic to process.