Ceramic and Glass Materials
172 O.A. Graeve in chemical formulas of the type ZrCaxO2-x, for the case of CaO doping, to maintain charge balance in the struct ...
10 Zirconia 173 in a neutral atmosphere, while the latter two measurements were done in a reducing atmosphere [6]. At increasing ...
174 O.A. Graeve 2.3 Monoclinic Zirconia EXAFS analysis by Winterer [10] and Li et al. [11] shows that monoclinic ZrO 2 can be de ...
10 Zirconia 175 Fig. 5 Crystal structure of monoclinic zirconia as seen from the [13–1] direction Table 3General crystallographi ...
176 O.A. Graeve calculations are in general agreement. This first orthorhombic phase (Pbca [16], Z = 8, coordination number = 7) ...
10 Zirconia 177 2.5 Amorphous Structure When ZrO 2 powders are prepared using any number of precipitation methodologies, the res ...
178 O.A. Graeve neighbors. The average Zr–O coordination distance is 0.255 nm for all eight oxygen neighbors. The local structur ...
10 Zirconia 179 atoms occupy the sites at the corners of the cubes, and metal cations occupy half of the sites at the center of ...
180 O.A. Graeve For the case of a singly-charged vacancy, the structural distortion results in the movement of surrounding oxyge ...
10 Zirconia 181 structure are given in Table 4 and were calculated using the Voigt, Reuss, and Hill approximations. The Voigt an ...
182 O.A. Graeve of 2.6 MPa m1/2 was extrapolated for a specimen of full density [36]. Slightly higher numbers of 3.7 ± 0.3 MPa • ...
10 Zirconia 183 a stress (Fig. 11a). If the composite contains metastable tetragonal particles, the large stresses at the tip of ...
184 O.A. Graeve s is the applied stress, p is the grain size exponent, n is the stress exponent, and D is the diffusion coeffici ...
10 Zirconia 185 However, the diffusion process is controlled by the Zr–Zr distance and not by the O–O distance, since the vacanc ...
186 O.A. Graeve conductivity are still a matter of controversy because of the complexity of the conduc- tion processes. Earlier ...
10 Zirconia 187 At the lower temperatures, the conductivity corresponds to the orthorhombic-II phase. From the Arrhenius plots i ...
188 O.A. Graeve P sRT = ⎛ ⎝⎜ ⎞ ⎠⎟ =× − ⎧ ± ⎨ 700 2 34 10− 45300 1200 2 Torr:D cm .exp^2 cal/mol ⎩⎩ ⎫ ⎬ ⎭ . (6) According to Ikum ...
10 Zirconia 189 Dlattice /s RT cm 2 kJ/mol ()=× − ⎧ ⎨ ⎩ ⎫ ⎬ ⎭ 484 10.exp−^12 87 0.. (8) These two expressions are not that very ...
190 O.A. Graeve in which the transformation is taking place [6]. In a reducing atmosphere, the trans- formation takes place at a ...
10 Zirconia 191 untransformed tetragonal phase. As the transformation progresses, the entire particle eventually forms the stabl ...
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