HTC shows off its process for making the super strong One S body
The process is called Micro Arc Oxidation, which is described in the video as being "almost like lightening striking the phone." Apparently, the way it works is that HTC starts with "aircraft 6000 grade aluminum" then hits it with 10,000 volts of electricity. That causes an oxidation process which forms a ceramic surface on the metal. The end result is a phone body that is 5 times stronger than aerospace aluminum and 3 times stronger than stainless steel.
HTC claims this means that you don't need a case because the phone itself is so strong. Definitely a pretty nice looking process, and the HTC One S was already looking like a pretty awesome phone.