Structural phase transition and ion conductivity in 0.88ZrO2−0.12Sc2O3

Rapid phase transformation of zirconia in the Ni-ScSZ cermet anode under reducing condition

“…First, a part of the cubic phase was transformed into the rhombohedrallike structure by annealing in the presence of nickel oxide in air at 1673 K. For Sc 2 O 3 doped zirconia, it is reported that the rhombohedral β phase is stable under about 873 K in the composition of 8-12 mol% Sc 2 O 3 -ZrO 2 [13,14] and this observation is supported by electrical conductivity measurement [15,16]. When 1 mol% of CeO 2 is added in 10 mol% Sc 2 O 3 -ZrO 2 , the cubic → β transformation is not observed and the cubic phase is stabilized at room temperature [17].…”

96Zr diffusion in polycrystalline scandia stabilized zirconia

“…In the concentration range where the highest oxygen conductivity is observed (10-12 mol% Sc 2 O 3 ), the rhombohedral ␤-phase is stable at temperatures below 500 and 600 • C. Some authors indicated the occurrence of a loss of ionic conductivity in scandia stabilized zirconia (ScSZ) coinciding with the phase transition between the cubic and the ␤-phase. 2 The maximum of the phase transition between the ␤-phase and the cubic phase was determined to be at a stabiliser content of 12 mol% Sc 2 O 3 and a temperature of 600 • C. [3][4][5][6][7][8] There is still controversy about the nature of the phase transition 1,5 and on hysteresis effects. 2,7,8 Both for YSZ and ScSZ, the ionic conductivity decreases for long annealing times.…”

“…2 The maximum of the phase transition between the ␤-phase and the cubic phase was determined to be at a stabiliser content of 12 mol% Sc 2 O 3 and a temperature of 600 • C. [3][4][5][6][7][8] There is still controversy about the nature of the phase transition 1,5 and on hysteresis effects. 2,7,8 Both for YSZ and ScSZ, the ionic conductivity decreases for long annealing times. 1 As the degradation process is directly related with the mobility of the cations in the lattice, the knowledge of diffusion data for the cations will allow a better understanding of the degradation process as well as of mechanical properties like the diffusion creep at high temperatures.…”

Solid oxide fuel cells with bi-layered electrolyte structure

“…This configuration is generally called a bi-layered electrolyte structure [8][9][10][11]. The ionic conductivity of scandiastabilized zirconia (SSZ) is the highest among all the ZrO 2 -based electrolytes [12]; however, it is not considered as a candidate electrolyte for reduced temperature SOFCs since its conductivity decreases rapidly with temperatures below 800 • C [13]. When a bi-layer SDC/SSZ electrolyte is used, the SSZ layer acts mainly as the barrier.…”