The effect of reduction on the mechanical properties of CeO2 doped tetragonal zirconia ceramics

Phase stability and microstructure evolution of yttria-stabilized zirconia during firing in a reducing atmosphere

“…The change of color for zirconia specimens after sintering in a reducing atmosphere had also been reported in previous studies [19,23]. The reducing atmosphere used in the present study is generated by firing the specimens within a graphite powder bed.…”

“…Besides using the stabilizers, the oxygen vacancy can also be created by heat-treating zirconia in an oxygen-lean environment. For examples, the solution of nitrogen into zirconia [11,19,21,22] and the use of flowing hydrogen [23] and carbon monoxide [24] can induce extra oxygen vacancy. In view of the applications for TBC and SOFC, the phase stability of YSZ in a reducing environment is an important issue.…”

The effect of hydrogen partial pressure on uniaxial creep of 3Y-TZP/50vol.% Pd cermet membranes

“…Matsuzawa et al have studied the effect of hydrogen reduction of several differently doped zirconia materials on mechanical properties: partially stabilized 3Y-TZP, fully stabilized 8Y-TZP (8 mol% Y 2 O 3 ), as well as CeO 2 and MgO doped zirconia (12 and 9 mol%, respectively) [33]. After exposing the samples to 1000 • C for 8 h in hydrogen gas, only the CeO 2 doped material was reduced, resulting in weight loss, increase in internal friction and hardness, as well as decrease in fracture toughness.…”

Influence of CeO2 Reduction on the Microstructure and Mechanical Properties of Pulsed Electric Current Sintered Y2O3–CeO2 Co‐Stabilized ZrO2 Ceramics

“…Heussner et al 8 observed an improved bending strength of 12 mol% Ce–TZP from 240 to 545 MPa after annealing in N 2 at 1400°C for 2 h. The increased toughness and strength were explained in terms of the partial reduction of Ce 4+ and segregation of Ce 3+ , resulting in a TZP matrix with enhanced transformability. On the other hand, a heat treatment of Ce–TZP in H 2 for 8 h at 1000°C was reported to increase the hardness but decrease the fracture toughness 14 …”

“…On the other hand, a heat treatment of Ce-TZP in H 2 for 8 h at 10001C was reported to increase the hardness but decrease the fracture toughness. 14 By a combinatorial approach of yttria co-stabilization and PECS, this study aims to investigate the possibility to fully densify CeO 2 -containing ZrO 2 ceramics in a graphite environment, while avoiding spontaneous catastrophic material degradation due to ceria reduction. The effect of the sintering condition on the phase composition, microstructure, and mechanical properties of as-sintered 1 mol% Y 2 O 3 16 mol% CeO 2 co-stabilized TZP, PECS in vacuum in a graphite die-punch set-up is investigated.…”