Phase Characterization of Precipitated Zirconia

Abstract

The phase compositions of undoped and europium-doped zirconia samples, obtained by precipitation and thermal treatment from 350" to lOOO"C, have been investigated by powder X-ray diffractometry, infrared spectroscopy, and cathodoluminescence spectroscopy. The low-temperature stabilization of tetragonal zirconia is mainly controlled by the presence of anion additives, such as ammonium chloride. The influence of the crystallite size is less important. Cathodoluminescence spectra show a structural similarity between tetragonal and amorphous zirconia.

Preparation and optical properties of transparent zirconia sol–gel materials

“…6 the NIR absorption spectra of gels prepared by the three preparation schemes A, B and C are shown. The sample M3 displays peaks at about λ max = 1900 nm (5263 cm − 1 ) and λ max = 2100 nm (4762 cm − 1 ) due to OH and H 2 O combination vibrations [6]. In the spectra of materials prepared with protection (acetylacetone and acetic acid) weak peaks at around λ max = 1200 nm (8333 cm − 1 ), λ max = 1400 nm (7142 cm − 1 ), λ max = 1700 nm (5882 cm − 1 ), λ max = 1920 nm (5208 cm − 1 ), λ max = 2300 nm (4347 cm − 1 ), λ max = 2500 nm (4000 cm − 1 ), and λ max = 2600 nm (3846 cm − 1 ) are observed.…”

“…The low working temperatures allow doping of the sol-gel glasses with organic dyes and d-and f-ion complexes. In this way new hybrid materials with interesting optical, electrical and mechanical properties are designed [1][2][3][4][5][6][7][8][9]. Zirconia (ZrO 2 ) is a suitable matrix for optical materials and coatings due to its high chemical and photochemical stability and its significantly lower phonon energy compared with SiO 2 and Al 2 O 3 [2][3][4][5].…”

Effect of Y2O3 addition on the phase transition and growth of YSZ nanocrystallites prepared by a sol–gel process

“…Moreover, a surface energy effect also contributes to the stability of the phase in pure and doped zirconias because the surface energy of the monoclinic phase (c m = 1.13 J/m 2 [27][28][29]) is higher than that of the tetragonal phase [30,31] (c t = 0.77 J/m 2 [26][27][28]). In yttria-doped zirconia, since the mass transport by surface diffusion is lower than for pure zirconia, crystal growth is hindered and phase transition is delayed [32,33].…”

HRTEM observation of the monoclinic-to-tetragonal m-t) phase transition in nanocrystalline ZrO2

“…The above considerations and the fact that the tetragonal particles observed in this work were, on average, smaller than the monoclinic ones (7.4 nm and 9.2 nm, respectively) confirm that. Adsorption of certain ions on the surfaces of the zirconia particles during their preparation could also act as a factor stabilizing t-ZrO 2 [46,47]. The first t → m transition can be attributed to the removal of these adsorbates due to the thermovacuum treatment inside the column of the electron microscope (pressure of 2.5⋅10 -5 Pa and temperature of [031] [011]…”