Zirconium polycrystalline

Fibre PRD-166 another polycrystalline continuous alumina fibre yam produced by DuPont in the 1980s. PRD-166 fibre yam is a modified form of FP fibre yam. The diameter of this fibre filament is 20 pm. The modification of FP fibre is made by incorporating 15-20 wt% yttria-stabilized zirconium particles. The idea of incorporating Y203-stabilized zirconia particles was to take care of problems such as unstable mechanical... 

Zr02+ 15 mole%CaO calcia-stabilized zirconium oxide 17.3.7 defect structure and mechanism of ionic conduction 17.3.7.3 oxygen ion resistivity of polycrystalline material 17.3.7... 

Calcia-stabilized zirconium oxide 18, 17.3.7 Defect structure and mechanism of ionic conduction 18,17.3.7.3 Oxygen ion resistivity of polycrystalline material 18, 17.3.7 OiZr... 

Sintered ceramics made of lead-zirconium titanate (PZT Pb(Tii jZr,)03 x S 0.5) are usually used for phoioacoustic experiments [105, 106]. The unit cell of the lead-zirconium titanate has a perovskite structure. Below the Curie temperature (328 °C for the PZT-4 (Vemitron) used by us [24]), the cells are tetragonally deformed, i.e., positive and negative charges are shifted and electric dipole moments are produced. In analogy to ferromagnetism, domains with randomly distributed polarization direction are formed. By the application of an electric field, these can be orientated in a preferred direction, and the sintered polycrystalline ceramic is then remanently polarized. The properties of these anisotropic piezoelectric materials are described by various parameters which depend on the polarization and deformation direction. In the common terminology, the < ordinate system shown in Fig. 3 is obtained for the cylindrical piezoelectric crystals [24]. 

Figure 23. Oxidation of polycrystalline zirconium at 700°C, comparison of calculated and actual oxidation (16)...

All the samples had a polycrystalline structure. Nevertheless, it has been established that the appearance of the isolated clusters of defects is observed in the FSZ structure at the initial stage of irradiation with high-energy xenon and iodine ions. In the sequel, the density of defects increases. However, at a relatively low dose of 3 dpa, the saturation stage is formed, and after its formation the material structure remains unchanged. The exposure of monoclinic zirconium oxide to the radiation dose of 2 dpa results in the transformation of monocUnic structme into more densely packed cubic and tetragonal structmes. During further increase in the radiation dose up to 680 dpa, amorphization is not observed. 

Yogo, T., S. Kodama, and H. Iwahara. 1993. Synthesis of polycrystalline alumina-zirconia fibre using chelated aluminum-zirconium precursor. Journal of Materials Science 28 105-110. ... 

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