When Apple signed an exclusive deal to use the superstrong alloy liquidmetal way back in 2010, there was a lot of speculation about how Apple might use it. The only immediate answer we saw was in the SIM ejection tool supplied with iPhones.

While some had expected Apple to use liquidmetal for product casings, the high cost of the material seemed to rule that out, at least in the short-term. There’s also been no sign of the super long-lasting batteries some had suggested.

But Apple clearly does have a use for it beyond SIM eject tools, last year renewing those exclusive rights – and a patent granted to the company today suggests one possible reason why …

The application for the material described in the patent is rather mundane, the patent suggesting liquidmetal could be used to improve the reliability and longevity of physical buttons on iDevices. Drawings in the patent suggest that the Home button on an iPhone is a likely candidate.

Conventional buttons have two problems, argues the patent. First, they are difficult to manufacture with the precision needed to provide a good feel.

Conventional assembly of such buttons implemented by dome switches is inefficient and complicated […] The placement of the actuation nubs relative to the domes is not always as accurate as desired. For example, if the actuation nub does not properly align with the center region of a dome, the tactile feedback for such dome switch will be disturbed and therefore not as robust as intended.

Second, they tend to become less responsive over time, failing to fully spring back to the open position.

Moreover, because this elastic limit is low, when it deforms it approaches its region of plastic deformation under low stresses with the risk that it cannot resume its initial form.

Liquidmetal solves both problems, the patent indicates. It’s not clear whether or not Apple is currently using the material in existing Home buttons but they do seem to last quite awhile.

So anyone hoping to see an iPhone or Mac casing made from liquidmetal may still have rather a long time to wait, but at least there’s a likelihood that at least some of the exotic material will be found under the skin.

Via Patently Apple