Engineers at the Naval Research Laboratory (NRL) have used nanotechnology to increase the toughness of the transparent spinel armor it currently uses on optics, sensors, and windows on ships and other vehicles. The new nanocrystalline spinel is made of the same materials, magnesium aluminate (MgAl2O4), but the grain size has been reduced to 28 nm.
Nanocrystalline spinel windows could be used on the Navy’s new Zumwalt Class of destroyers, like the USS Zumwalt pictured above.
The NRL team created the windows by sintering nanopowders under high pressures. Pressure breaks down the powders into smaller particles, slows them from diffusing out of the mixture, and pushes them closer together to reduce porosity in the final material. The new armor is tougher than the spinel currently used, so it can be made thinner, resulting in a cost and weight savings.
Researchers are now working to make even tougher versions of the new armor, hoping to replace the sapphire windows used in military vehicles. Sapphire windows are much more expensive to produce.
The NRL-developed armor is also highly transparent, so it could also be used in UV, visible, and IR optics, which should simplify design requirements. There are potential civilian uses for the see-through material in smartphones and tablets screens, windows for homes and offices, and space vehicles, including extraterrestrial rovers.
