Powder was prepared by using the citrate process, and sintered using the SPS method where the specimen was sintered at lower temperatures; with grain growth suppressed. The powder had a cubic phase with a crystallite size of about 340Å. The SPS method provided densely-sintered specimen of cubic phase at room temperatures after sintering below 1100C; with a crystallite size of around 370Å. After air-sintering at 1500C, it was as large as 650Å. The electrical conductivity of SPS specimens increased in the lower temperature range (400 to 670C), but decreased in the higher range (680 to 800C); in contrast to air-sintered specimens. When the transition point was lowered near to room temperature, the discontinuity in conductivity at around 670 to 680C was eliminated.

Phase Transition and Electrical Conductivity of Scandia-Stabilized Zirconia Prepared by Spark Plasma Sintering Process. M.Okamoto, Y.Akimune, K.Furuya, M.Hatano, M.Yamanaka, M.Uchiyama: Solid State Ionics, 2005, 176[7-8], 675-80