Zirconium dioxide coating on particles of titanium dioxide pigments, as a refractory material, in insulation, abrasives and enamels. Stabilized zirconia is used in oxygen sensors and fuel cell membranes because it has the ability to allow oxygen ions to move freely through the crystal structure at high temperatures. This high ionic conductivity (and a low electronic conductivity) makes it one of the most useful electroceramics. Zirconium dioxide is also used as the solid electrolyte in electrochromic devices. Zirconia is a precursor to the electroceramic lead zirconate titanate ("PZT"), which is a high-K dielectric, which is found in myriad components. The very low
Cubic zirconia a strong, complex rare earth absorption spectrum. Discovered in 1892, the yellowish monoclinic mineral baddeleyite is a natural form of zirconium oxide. The high melting point of zirconia (2750 °C or 4976 °F) hinders controlled growth of single crystals. However, stabilization of cubic zirconium oxide had been realized early on, with the synthetic product "stabilized zirconia" introduced in 1929. Although cubic, it was in the form of a polycrystalline ceramic: it was used as a refractory material, highly resistant to chemical and thermal attack (up to 2540 °C or 4604 °F). In 1937, German mineralogists M. V. Stackelberg and K.