MODEL: B-OZZirconium dioxide is one of the most studied ceramic materials. ZrO2 takes a monoclinic crystal structure at room temperature and the transition to tetragonal and cubic at higher temperatures. Volume expansion due to the cubic to tetragonal to monoclinic transformation induces caused great tensions, and these stresses cause ZrO2 to crack upon cooling from high temperatures. If the ziconia is mixed with other oxides, the tetragonal and / or cubic phases are stabilized. effective dopants include magnesium oxide (MgO), yttria (Y2O3, yttrium oxide), calcium oxide (CaO) and cerium (III) oxide (Ce2O3).Zirconia is often 'stabilized' useful in the phase state. Upon heating undergoes zirconia disturbing phase changes. By addition of small amounts of yttrium oxide, this phase will be omitted, and the resulting material has excellent thermal, mechanical and electrical properties. In some cases, the metastable tetragonal phase to be. If sufficient quantities of the metastable tetragonal phase is present, then an applied voltage, increased by the stress concentration at the crack tip, the tetragonal phase to convert to monoclinic, with the associated volume expansion. This phase transformation can then make the leap into the compression, retarded growth and improvement in fracture toughness. This mechanism is known as transformation toughening, and significantly extends the reliability and service life of products made with stabilized zirconia.The ZrO 2 band gap depends on the phase (cubic, tetragonal, monoclinic, or amorphous) and preparation methods, with typical estimates of 5-7 eV.A special case of zirconia is that the polycrystalline tetragonal zirconia or TZP, which is composed indicative of polycrystalline zirconia only the metastable phase. Read more:Zirconium Dioxide MODEL: OZ-B for sale
