An investigation of the zirconia-gadolinia system

Phase diagram of the ZrO2–Gd2O3–Al2O3 system

“…5,[35][36][37][38] The system ZrO 2 -Al 2 O 3 has been assessed by Fabrichnaya et al 21 However, the parameters of this system have been re-assessed in this study because of the necessity to use other models for the fluorite and tetragonal phases than were used in work. 21 There are no experimental thermodynamic data for this system, that is why only phase equilibrium data have been used in the optimisation.…”

Up-Date of a Thermodynamic Database of the ZrO2-Gd2O3-Y2O3-Al2O3 System for TBC Applications

“…[23,[26][27][28][29][30][31][32][33] The calculated data for invariant reactions (temperature and phase compositions) are compared in Table 2 with experimental data. [26][27][28]34,35] The difference with the previous assessment of Lakiza et al [15] is that the F + Pyr two-phase field is narrower and there is no eutectoid reaction F = M + Pyr which was obtained at lower temperatures in the calculations. [15] However, experiments can not distinguish between the single phase pyrochlore and the F + Pyr two-phase field and there is still discussion in the literature if the transformation of Fluorite to Pyrochlore is of the first or second order.…”

Phase equilibria in the ZrO2–GdO1.5 system at 1400–1700°C

“…The unit-cell parameter of the fluorite phase and the reduced lattice parameter of the pyrochlore phase (divided by factor of 2) determined in this work as well as those from the literature [2,4,[7][8][9][10][11][12][13]18,19,[26][27][28][29][30] are shown in Fig. 3.…”

“…The tetragonal polymorphic modification of zirconia (T) is known to dissolve up to 3 mol% GdO 1.5 [12,15]. The invariant reaction T ⇔ M + F, which corresponds to the eutectoid decomposition of the tetragonal phase was found to occur at 1140-1145 • C [7]. The cubic fluorite-type phase Zr 1 − x Gd x O 2 − x/2 (F) is stabilized in a wide range of composition and temperatures [3,4,6,8,12,15].…”

“…Phase diagram studies of the system ZrO 2 -GdO 1.5 have been performed by Perez y Jorba [3], Lefevre [4], Rouanet [5,6], Negro and Amato [7], Scott [8] and Uehara et al [9] by using X-ray diffraction (XRD) and thermal analysis. In addition, particular phase equilibria have been investigated with the X-ray diffraction, Raman and Mössbauer spectroscopy, pertrographic analysis as well as the electron probe microanalysis in the limited temperature and/or composition ranges [10][11][12][13][14][15][16][17][18][19][20][21].…”