Yttria-stabilized zirconia pellets were consolidated by pressureless sintering and spark plasma sintering. The consolidated pellets varied in relative density from 40 to 99.5 % (as determined through Archimedes method) and were characterized via x-ray diffraction (XRD), optical microscopy, and scanning electron microscopy. Using a custom-built flame rig, each pellet was placed in intimate contact with AFRL-02 synthetic sand and exposed to an oxy-acetylene flame (surface temperature ~ 1300 ?C) for 15 minutes. Subsequent characterization results were compared to the corresponding pre-test data to draw conclusions on the degree of infiltration and calcia-magnesia-alumino-silicate (CMAS) formation. No significant chemical reactions were observed, but XRD results do show synthetic quartz formation, with a peak shift of 2? ~ 0.5? that may indicate compressive stress. In addition to the normal routes of cracks and voids, significant infiltration along the grain boundaries of high density samples (99.5%) was also observed.
