Effect of Spark Plasma Sintering (SPS) on the Microstructure, Mechanical Property and Thermal Conductivity of Plasma Sprayed YSZ Electrolyte

摘要

Freestanding yttria stablized zirconia (YSZ) electrolyte discs with a diameter of 13 mm is prepared by the plasma spray technique. Single and multiple cycles of spark plasma sintering (SPS), as post-spray treatment, at 1200°, 1400° and 1500℃ with holding time 3 and 9 minutes are performed on the YSZ electrolyte discs. The microstructure of as-received and SPS treated electrolytes is examined by SEM. The mechanical properties and thermal conductivity of the electrolytes is measured to ascertain the effect of SPS. The results show that following SPS, the lamella structure of the plasma sprayed discs turned into equi-axial granular structure. The micro-hardness and Young's modulus of the electrolyte increases with the increase of SPS temperature and cycles, and slight decrease was detected with a soak time of 9 minutes compared to that with a soak time of 3 minutes. The thermal conductivity of the electrolytes is greatly improved after SPS treatment.