Imaging Secondary‐Ion Mass Spectroscopy Observation of the Scavenging of Siliceous Film from 8‐mol%‐Yttria‐Stabilized Zirconia by the Addition of Alumina

Abstract

The scavenging of a resistive siliceous phase via the addition of Al 2 O 3 was studied, using imaging secondary‐ion mass spectroscopy (SIMS), given the improved grain‐boundary conductivity in 8‐mol%‐yttria‐stabilized zirconia (8YSZ). The grain‐boundary resistivity in 8YSZ decreased noticeably with the addition of 1 mol% of Al 2 O 3 . Strong SiO 2 segregation at the grain boundaries was observed in a SIMS map of pure 8YSZ that contained 120 ppm of SiO 2 (by weight). The addition of 1 mol% of Al 2 O 3 caused the SiO 2 to gather around the Al 2 O 3 particles. The present observations provided direct and visual evidence of SiO 2 segregation at the grain boundaries (which had a deleterious effect on grain‐boundary conductivity) and the scavenging of SiO 2 via Al 2 O 3 addition.