Microstructural, mechanical, and electrical characteristics of alumina-reinforced ytterbia-stabilized cubic zirconia-based composites

摘要

Al_2O_3-dispersed Yb_2O_3-stabilized cubic-ZrO_2 (YbSZ) composites are fabricated by pressureless sintering of composite powders to obtain fine and homogeneous microstructures by the solution chemistry route. Al_2O_3 particles are deposited on ZrO_2 powders by the precipitation of aluminum nitrate followed by calcination in air. The sinterability of the composites was affected by the calcination temperature. Microstructures of the sintered bodies are dependent on the Al_2O_3 content. For the 5 vol% Al_2O_3-dispersed composite, fine Al_2O_3 particles were mainly located inside the grains of zirconia, whereas relatively large Al_2O_3 particles almost dispersed at the grain boundaries when the Al_2O_3 content was increased. The grain growth of YbSZ was suppressed by the Al_2O_3 addition, and the refinement of the matrix grain improved the fracture strength of YbSZ. The YbSZ and YbSZ/Al_2O_3 composites exhibited almost similar ionic conductivity at high temperatures of around 1000℃.