Zirconia
Zirconium dioxide (ZrO2) or zirconia is a chemically inert, high-strength and low thermally conductive ceramic that can be used in many applications. Zirconia occurs naturally in a monoclinic crystalline form and other crystal structures are produced using stabilizing dopants. A popular form for the consumer market is stabilized cubic zirconia as a synthetic diamond or gemstone for jewelry. The stabilized tetragonal form of zirconia has very high toughness and wear resistance. This allows zirconia to be used as bearings in applications where heat and chemical resistance would limit the use of metal bearings.
Zirconia has high ionic oxygen conductivity at high temperatures allowing its use as an electro-ceramic, such as an oxygen sensor or fuel cell membrane. Other applications of zirconia that take advantage of the material’s high strength, toughness and wear resistance include dental restorations and ceramic knives and cutting blades. Zirconia is used as an optical coating due to its high index of refraction from the near-UV to the mid-IR. CeraNova produces a transparent form of zirconia that transmits in the same region that could be used in window and dome applications.
Nanoceramic Composites
The design, production and application of composites as optical materials is challenging due to the degradation in optical properties that can occur when two dissimilar materials are combined. Some polymer/glass fiber composites are used as optical components where improved mechanical properties are needed. Recently, a new class of optical composites has been developed where the microstructure is tailored to produce properties not possible in the single component materials. Properties can be varied through compositional gradients or by combining individual, immiscible materials on very fine scale.
CeraNova was a member of Raytheon’s Nano-Composite Optical Ceramic (NCOC) material team where one such unique composite was developed under a four-year DARPA (Defense Advanced Research Projects Agency) project. This new optical composite provides a revolutionary improvement in IR-transmitting windows, combining a distinctive balance of optical and mechanical performance.