R. P. Ingel

Infrared spectra in nonstoichiometric yttria‐stabilized zirconia mixed crystals at elevated temperatures

Infrared (IR) reflectivity measurements were undertaken on pure ZrO2 and stabilized ZrO2⋅Y2O3 solid solutions containing 3‐, 4‐, 7‐, 12‐, and 20‐wt.% Y2O3 over 10–900 cm−1 region as a function of temperature up to 1400 °C. The observed IR active phonons are related to the phase transitions that depend on composition and temperature. Good agreement was achieved among IR, Raman scattering, and neutron scattering investigations. An IR reflectivity enhancement from 42% to 60% in the low‐frequency region (10–110 cm−1) was found as the monoclinic(M)‐tetragonal(T) martensitic transition was completed in pure ZrO2 and ZrO2⋅3‐wt.% Y2O3.

On the determination of the piezoelectric shear coefficient, d15, in a PZT ceramic

Abstract The polarization obtained in the direction of an arbitrary uniaxial stress is derived by applying tensor transformations to the polarization-stress relation: Pi , = dijkσjk . Two- and three-dimensional plots of the results are shown. The experimental work described includes the preparation of discs poled uniformly at 90° to their thickness and the measurement of d 333 as a function of orientation. Very good agreement with the calculated results was obtained. The effect of electrodes on the measurement of d 333 (d 33) and the use of a d 311 (d 31) parameter measurement to permit a d 113 (d 15) determination are also demonstrated. The d 333 measurements as a function of stress orientation permitted determination of the d 15 value with a resolution of ±8%. Its average value was within 5% of d 15 values derived from other techniques.

Low‐frequency Raman spectra in disordered cubic zirconia at elevated temperatures

Rayleigh wing broadening (quasielastic scattering) was found at high temperatures (650–1500 K) in cubic zirconia single‐crystal ZrO2 fully stabilized with Y2O3; however, broadening was not observed in the two‐phased cubic plus tetragonal zirconia crystals. We believe this can be interpreted as a disorder‐order transition as the configuration goes from single‐phase cubic‐to‐cubic plus tetragonal structure with less addition of Y2O3. Theoretical agreements were achieved by utilizing ‘‘rigid ion model’’ and ‘‘decay model’’ calculations.

Partially Stabilized ZrO2 As A Possible Ir Dome Material

There is increasing interest in IR window materials with transmissionn limits of > 5 μm, increased mechanical toughness, and higher temperature capability. ZrO2, which transmits to 7-8 μm is a possible candidate material for such needs. While its IR cut-off is at somewhat shorter wavelengths than other candidates (e.g. Y203 with a cut-off of - 9 μm), ZrO2 offers the potential of significant toughening via a two phase, i.e. partially stabilized, structure. Such structures, and the relevant toughening mechanisms are reviewed, and the resultant mechanical properties discussed, particularly for the Zr02-Y203 system. For example, some materials in this system can give strengths of about 1.5 GPa (200,000 psi) at 22°C and nearly 0.7 GPa (100,000 psi) at 1500°C for laboratory test specimens. Preliminary optical measurements, including some outlining optical scattering effects of the second (precipitate) phase, required for mechanical toughening are presented. These suggest that useful transmission in the range of interest is achievable with these toughened ZrO2 materials.

Partially Stabilized ZrO 2 As A Possible Ir Dome Material

There is increasing interest in IR window materials with transmissionn limits of > 5 μm, increased mechanical toughness, and higher temperature capability. ZrO2, which transmits to 7-8 μm is a possible candidate material for such needs. While its IR cut-off is at somewhat shorter wavelengths than other candidates (e.g. Y203 with a cut-off of - 9 μm), ZrO2 offers the potential of significant toughening via a two phase, i.e. partially stabilized, structure. Such structures, and the relevant toughening mechanisms are reviewed, and the resultant mechanical properties discussed, particularly for the Zr02-Y203 system. For example, some materials in this system can give strengths of about 1.5 GPa (200,000 psi) at 22°C and nearly 0.7 GPa (100,000 psi) at 1500°C for laboratory test specimens. Preliminary optical measurements, including some outlining optical scattering effects of the second (precipitate) phase, required for mechanical toughening are presented. These suggest that useful transmission in the range of interest is achievable with these toughened ZrO2 materials.

Partially Stabilized ZrO[sub]2[/sub] As A Possible Ir Dome Material

There is increasing interest in IR window materials with transmissionn limits of > 5 μm, increased mechanical toughness, and higher temperature capability. ZrO2, which transmits to 7-8 μm is a possible candidate material for such needs. While its IR cut-off is at somewhat shorter wavelengths than other candidates (e.g. Y203 with a cut-off of - 9 μm), ZrO2 offers the potential of significant toughening via a two phase, i.e. partially stabilized, structure. Such structures, and the relevant toughening mechanisms are reviewed, and the resultant mechanical properties discussed, particularly for the Zr02-Y203 system. For example, some materials in this system can give strengths of about 1.5 GPa (200,000 psi) at 22°C and nearly 0.7 GPa (100,000 psi) at 1500°C for laboratory test specimens. Preliminary optical measurements, including some outlining optical scattering effects of the second (precipitate) phase, required for mechanical toughening are presented. These suggest that useful transmission in the range of interest is achievable with these toughened ZrO2 materials.