Martensitic Transformation in Deoxidized Ceria-Zirconia Ceramics

Ce(IV) ion in ceria doped zirconia ceramics was completely reduced to Ce(III) ion after deoxidation in hydrogen atmosphere above 1073 K. This deoxidation resulted in a weight loss due to the formation of oxygen vacancies. Tetragonal xCeO_1.5-(1-x)ZrO₂ ceramics of 0.06≤x≤0.16 were obtained after deoxidation above 1073 K. The martensitic transformation of ceria-zirconia ceramics was affected by this deoxidation. The starting temperature of martensitic transformation (Ms) was lowered by this deoxidation, e.g., https://www.w3.org/1998/Math/MathML"> Ms = 1173  K https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003421290/07e4de97-c68f-4ca1-95b4-28d8b410031d/content/eq154.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> and 240 K for 0.06CeO₂-0.94ZrO₂ and 0.06CeO_1.5-0.94ZrO₂ respectively. These deoxidized ceramics were also stable under mechanical stress and no monoclinic phase appeared after grinding in an agate mortar. The formation of oxygen vacancies may play an important role in the martensitic transformation in zirconia ceramics.