Phase assembly and microstructure of CeO2-doped ZrO2 ceramics prepared by spark plasma sintering

Nanostructured Spark Plasma Sintered Ce‐TZP Ceramics

“…During SPS, a strongly reducing atmosphere is created around the powder by the graphite die and punches. Different studies have shown the catastrophic degradation and cracking of samples when sintering in hot pressing or graphite furnace . Huang et al .…”

“…have reported the partial retention of tetragonal phase in 8 mol% CeO 2 ‐doped ZrO 2 , spark plasma sintered at 1300°C without holding time. Besides the t‐ZrO 2 phase, a 66 vol% monoclinic phase and a trace amount of a Zr–Ce–O cubic solid solution were found . However, the nanostructure was not achieved in this study.…”

“…[19][20][21] In the last few years, few attempts of processing CeO 2 -ZrO 2 solid solution or related systems by means of SPS have been carried out. 16,22,23 The main problem of SPS on Ce-TZP is the susceptibility to reduction of CeO 2 to Ce 2 O 3 in vacuum or low oxygen partial pressure atmospheres, which has an effect on the stability of the tetragonal zirconia phase at room temperature. During SPS, a strongly reducing atmosphere is created around the powder by the graphite die and punches.…”

Constraint of Oxygen Fugacity During Field‐Assisted Sintering: TiO2 as a Test Case

“…Nanocrystalline TiO 2 ceramics particularly processed by FAST have been reported to have an unusual high dielectric constant and low dielectric loss possibly due to the space charges produced by reduction of Ti 4+ during sintering 7 . While recent FAST studies emphasize effects of DC pulsing, 8 electric field/electrical current, 9–13 and high heating rate, 14 the reduction of ceramics sintered by FAST was only qualitatively documented 7,15,16 . No work has been done to systematically study the reducing environment and how ceramics respond to it.…”

“…7 While recent FAST studies emphasize effects of DC pulsing, 8 electric field/electrical current, [9][10][11][12][13] and high heating rate, 14 the reduction of ceramics sintered by FAST was only qualitatively documented. 7,15,16 No work has been done to systematically study the reducing environment and how ceramics respond to it. TiO 2 (rutile) is known as an oxygen-deficient oxide 17 which has a narrow range of phase stability with oxygen pressure.…”