Imagine a camera lens that does not get scratched in a sand storm, or a smartphone that does not break when dropped. A new transparent material that the US Navy has developed from special ceramic called spinel could make such gadgets a reality.
"It is a game-changing technology," said lead researcher Jas Sanghera from the US Naval Research Laboratory (NRL). "Spinel is actually a mineral, it is magnesium aluminate," Sanghera explained.
As a more durable material, a thinner layer of spinel can give better performance than glass and it could be used for watches and consumer electronics, like the smartphone. "The advantage is it is so much tougher, stronger, harder than glass.
It provides better protection in more hostile environments -- so it can withstand sand and rain erosion," Sanghera pointed out. NRL invented the new way of making transparent spinel using a hot press called sintering.
It is a low-temperature process, and the size of the pieces is limited only by the size of the press. "Ultimately, we are going to hand it over to industry, so it has to be a scalable process," Sanghera pointed out. In the lab, they made pieces eight inches in diameter.
"Then we licensed the technology to a company who was able then to scale that up to much larger plates, about 30-inches wide." The sintering method also allows NRL to make optics in a number of shapes, "conformal with the surface of an airplane or UAV wing," depending on the shape of the press.
In addition to being tougher, stronger, harder, spinel has "unique optical properties; not only can you see through it, but it allows infrared light to go through it", Sanghera said.
That means the military, for imaging systems, "can use spinel as the window because it allows the infrared light to come through". Whereas with glass, a crack that forms on the surface will go all the way through, spinel might chip but it would not crack, the researchers explained.