Thermal stability and phase transformation in fully indium oxide (InO1.5) stabilized zirconia

Author(s)

Piva, R. H. ^[1] ; Piva, D. H. ^[1] ; Morelli, M. R. ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Mat Engn Dept PPG CEM, Lab Ceram Synth & Formulat, Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: MATERIALS CHARACTERIZATION; v. 123, p. 58-66, JAN 2017.
• Web of Science Citations: 1

Abstract

Indium oxide (InO1.5) stabilized zirconia (InSZ) is an attractive material as electrolyte, or electrode, in solid oxide fuel cells (SOFCs, and as corrosion resistant top coat in thermal barrier coatings. However, little is known about the phase stability of cubic InSZ at temperatures that simulate the conditions in an operating SOFC or turbine. This article provides an investigation of the phase stability and phase transformations in cubic InSZ after heat treatments at 800,1000, and 1200 degrees C for periods up to 2000 h. The results revealed that cubic InSZ is not stable during annealing at 1000 and 1200 degrees C, owing to a fast destabilization of the initial cubic phase to tetragonal, and eventually to monoclinic (c -> t -> m). The c -> t -> m transition in InSZ is intimately associated with the indium volatilization. On the other hand, cubic InSZ remained stable for 2000 hat 800 degrees C, although the partial formation of the tetragonal phase was observed along with a 0.25% contraction in the unit cell volume of the cubic phase, caused by short-range ordering. These results demonstrate that technological applications of cubic InSZ are restricted to temperatures at which the volatilization of the InO1.5 stabilizer does not occur. (C) 2016 Elsevier Inc All rights reserved. (AU)

• FAPESP's process: 13/14189-8 - Nb2O5/Ta2O5 + Sc2O3 codoped zirconia as a thermal barrier coating for turbines application
• Grantee: Roger Honorato Piva
• Support Opportunities: Scholarships in Brazil - Doctorate