Calculated High‐Temperature Elastic Constants for Zero Porosity Monoclinic Zirconia

Abstract

has not been reported in the literature. Figure 4 shows the spectrum of monoclinic zirconia with two absorption bands, one at 270 cm-' and another at 230 cm-l. The absorption band occurring at 270 c m -I is fairly asymmetric indicating the possibility of another absorption band lying close to it.The infrared transmission spectrum of the cubic zirconia is quite transparent in this region and gave no indications of any absorption when recorded as a capillary film in Nujol 0 c IV. DiscussionThe infrared spectrum of ZrOz is quite characteristic and from this study would seem to be useful for identification and in solid state research. Infrared spectra are quite dependent Vol. 47, No. 12 A method was developed for hot-pressing 80 to 95% dense, polycrystalline specimens of commercially available, unstabilized, monoclinic zirconia. T h e elastic moduli of these specimens were measured by a sonic method in t h e range 25' to 100O'C. Application of mathematical expressions developed for the porosity dependence of elastic moduli of refractory oxides led to the calculation of Young's and shear moduli of this material at zero porosity in this temperature range. . 1 R. M. Spriggs, "Expression for Effect of Porosity on Elastic Modulus of Polycrystalline Refractory Materials, Particularly Aluminum Oxide," J . Am. Ceram. Soc.,44 I121 628-29 (1961). R. M. Spriggs and L. A. Brissette, "Expressions for Shear Modulus and Poisson's Ratio of Porous Refractory Oxides," J . Am. Ceram. Soc., 45 [4] 198-99 (1962). a R. M. Spriggs, L. A. Brissette, and T. Vasilos, "Effect of Porosity on Elastic and Shear Moduli of Polycrystalline Magnesium Oxide," J . Am. Ceram. SOL, 45 [8] 400 (1962).

Pressure-induced structural phase transitions in zirconia under high pressure

“…This is smaller than a value of 135 GPa deduced from the shear and elasticity moduli of polycrystalline samples measured under normal conditions and extrapolated to zero porosity. 46 Recent Brillouin scattering experiments 47 at normal pressure performed on single crystals gave a mean value of 185 GPa, but these measurements could have been perturbed by twinning as large crystals of the monoclinic phase are extremely difficult to make. From shock-wave data, the bulk modulus was inferred to be 149 GPa.…”

Elastic constants of the iron oxide doped yttria-stabilized zirconia

“…Bulk density -WT QT (1) where Ws denotes the weight of specimen in air, WT is the apparent weight loss in toluene, and ~o T is the density of toluene. The true density (D) of the specimens was determined using the pycnometer according to the following expression:…”

Thermal Expansion Reduction in Alumina‐Toughened Zirconia by Incorporation of Zirconium Tungstate and Aluminum Tungstate

“…The reagent compositions and the final compositions are given in Tables and , respectively. The bulk modulus and CTE values used were as follows: ZrW 2 O 8 , 13 GPa and −5 × 10 −6 K −1 (β phase); Al 2 W 3 O 12 , 46 GPa (determined here; see the Appendix) and 2 × 10 −6 K −1 ; Al 2 O 3 , 254 GPa and 8 × 10 −6 K −1 ; ZrO 2 , 187 GPa , and 7 × 10 −6 K −1 . The rule of mixtures gave inaccurate predictions of the CTEs of the products.…”