According to the research report conducted by Naval Research Laboratory, the Department of Defense in Untied States was seeking materials with a high degree of transparency for armor windows in order to provide essential protection for both personnel and equipment. To meet that need, scientists at NRL have developed a method to fabricate nanocrystalline spinel which is 50% harder than the current spinel armor materials used in military vehicles. The project of NRL’s nanocrystalline spinel demonstrated that the hardness of the transparent ceramic material could be improved as long as the grains size could be reduced to 28 nanometers, which made the hardness of the nanocrystalline spinel reach up to an unprecedented level. This harder spinel can be used to make better armor windows for military vehicles, providing better protection for the personnel and equipment, such as the sensors, as well as with other benefits.

The biggest advantage of NRL’s nanocrystalline spinel is that its high degree of transparency makes it available in making UV, visible and infrared optics. High transparency is required for Armor Windows used in military vehicles so that both the personnel and the equipment in the vehicle can see clearly. Different sensors "see" different wavelengths of light. Infrared can be used in heat-seeking devices while UV imaging is often used to detect the threats that can’t be seen in the visible spectrum. The transparency of the window made of NRL’s nanocrystalline spine can let all kind of important light through, which can simplify the system design and meet weight requirements as well.

Besides the application in the military realm, there is much more potential for the harder nanocrystalline spinel, such as the application in the field of national defense and civilian areas, including its application in making office windows, the screens of smart phones and tablets, the windows used in military and civilian vehicles and even space vehicles and extraterrestrial rovers. However, in consideration of the cost and practicality, laminated tempered glass, a kind of safety glass, is more widely used in civilian areas now. For example, the laminated tempered glass produced by LandGlass’ tempering furnaces is widely used in many areas, such as architectures, furniture, household appliances, automobiles and solar energy industries.