Effect of alumina additions on mechanical and electrical properties of 8mol% yttria-stabilized zirconia prepared by spark pplasma sintering

Dense 8 mol% yttria-stabilized zirconia (8YSZ) consisting of submicrometer-sized grains was prepared using spark plasma sintering (SPS) along with Al2O3 additives. The starting powder with average particle size of 50nm was densified to 98% of the relative density with short sintering time (5min) at 1200 degrees C while preserving a submicrometer grain size. The fracture toughness and bending strength showed maximum values of 2.54MPam(1/2) and 380MPa at 2vol% alumina-added 8YSZ, due mainly to the higher relative density and small grain size. The electrical conductivity of 2vol% alumina-added 8YSZ was 0.0278 S/cm at 700 degrees C in air. Thus, alumina additions in 8YSZ using the SPS method are an effective process to improve the mechanical strength and electrical conductivity.