Resistance of InO1.5-stabilized tetragonal zirconia polycrystals to low-temperature degradation

Autor(es)

Piva, Diogenes Honorato ^[1] ; Piva, Roger Honorato ^[1] ; Rocha, Marina Campos ^[2] ; Klegues Montedo, Oscar Rubem ^[3] ; Morelli, Marcio Raymundo ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Lab Ceram Synth & Formulat, BR-13560 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Ctr Biol Sci & Hlth, Dept Genet & Evolut, BR-13560 Sao Carlos, SP - Brazil

^[3] Univ Extremo Sul Catarinense, Lab Ceram Tecn CerTec, Criciuma, SC - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Materials Letters; v. 163, p. 226-230, JAN 15 2016.
• Citações Web of Science: 1

Resumo

9 mol% InO1.5-stabilized zirconia (ISZ) was synthesized using a coprecipitation method. Sintered samples were hydrothermally degraded for periods of up to 40 h in an autoclave at 134 degrees C and 2 bar. The tetragonal to monoclinic phase transformation (t-m) was observed by X-ray diffraction (XRD) and atomic force microscopy (AFM). An increase in surface roughness, associated with the martensitic t-m transformation was observed by AFM. According to XRD patterns, 30 vol% of the tetragonal phase initially present in the ISZ sample transformed into the monoclinic phase after the hydrothermal degradation. The impact of the transformation was evaluated in terms of structural integrity. Vickers hardness was not affected, however the flexure strength decreased by about 43% after autoclave treatment for 10 h. A key finding from this study is that, despite a rapid decrease of flexure strength during initial autoclaving step, ISZ presents a lower trend to t-m transformation than the currently used 3 mol% yttria-stabilized zirconia material. The high concentration of oxygen vacancies and low tetragonality of 9 mol% ISZ seem to be responsible for its superior resistance to hydrothermal degradation. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/14189-8 - Revestimentos de zircônia codopada com Nb2O5/Ta2O5 + Sc2O3 como barreira térmica para aplicação em turbinas
• Beneficiário: Roger Honorato Piva
• Modalidade de apoio: Bolsas no Brasil - Doutorado