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Low temperature degradation of a Y-TZP dental ceramic

Paper ID Volume ID Publish Year Pages File Format Full-Text
995 70 2011 8 PDF Available
Title
Low temperature degradation of a Y-TZP dental ceramic
Abstract

Bars of Y-TZP ceramic for dental restorations were subjected to hydrothermal degradation via in vitro exposure to water steam at 140 °C for 7 days. X-ray diffraction, atomic force microscopy and scanning electron microscopy techniques were applied to observe and quantify the tetragonal–monoclinic (t–m) phase transformation associated with the process. Nanoindentation was used to assess the ceramic’s mechanical properties before and after hydrothermal degradation. Texture associated with martensitic t–m transformation was observed at the grain surface. The t–m transformation followed nucleation-and-growth kinetics, with predominance of the nucleation process. The transformation occurred within a layer of 6 μm below the surface.Mechanical properties deteriorated with hydrothermal degradation, resulting in a 30% reduction of Young’s modulus and hardness. A strong correlation was found between the increasing monoclinic fraction and the decline in mechanical response. It was thus concluded that the emergence of the monoclinic phase and the associated microcracking were the most likely causes for the degradation of mechanical properties.

Keywords
Zirconia; Low temperature degradation; Tetragonal-to-monoclinic transformation; Dental ceramics; Mechanical properties
First Page Preview
Low temperature degradation of a Y-TZP dental ceramic
Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 7, Issue 2, February 2011, Pages 858–865
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering