Direct evidence for continuous linear kinetics in the low-temperature degradation of Y-TZP

Keuper, Melanie; Eder, Katja; Berthold, Christoph; Nickel, Klaus G.

doi:10.1016/j.actbio.2012.08.032

Cited by 65 publications

(60 citation statements)

References 39 publications

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“…However, this method for quantification has some major drawbacks for the evaluation of implant surfaces since the calibration curve of Toraya et al [32] is based on homogeneous mixtures of ZrO 2 powders with various monoclinic-tetragonal ratio. As already mentioned before, phase transformation during the low temperature degradation of zirconia starts on the surface and proceeds linearly into the volume of the ceramic with time [7]. Thus, any measurement spot on the surface of an aged Y-TZP part comprises a surface layer of higher monoclinic content with an underlying tetragonal layer of virtually infinite thickness.…”

Section: Suitability Of Xrd For Quantification Of Monoclinic Phase Atmentioning

confidence: 94%

“…In conclusion, ISO 13356 does not account for the real transformation rate of samples with roughened surface and a non-porous bulk [9]. Even if experimental methods to predict and simulate LTD in a given zirconia ceramic are deemed to be highly accurate [7,14], the impact on reliability of final implant designs in combination with stress-inducing dynamic fatigue has not yet been evaluated. There is no standardized protocol available, allowing to assess the effect of aging and simultaneous dynamic fatigue on the mechanical properties of a given type of implant.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to stress-triggered PTT, LTD is defined as spontaneous and progressive t-m transformation at low temperatures in the presence of water molecules. Once started, phase transformation continuously progresses from the surface into the volume in a layer-by-layer manner, following a linear time law [7]. Aging can result in intergranular micro-cracking, surface-roughening and, up from a certain level, in reduced strength [8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Long-term stability of an injection-molded zirconia bone-level implant: A testing protocol considering aging kinetics and dynamic fatigue

et al. 2017

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Section: Suitability Of Xrd For Quantification Of Monoclinic Phase Atmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Long-term stability of an injection-molded zirconia bone-level implant: A testing protocol considering aging kinetics and dynamic fatigue

et al. 2017

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“…Typically, the tetragonal to monoclinic phase transformation causes undoped specimens to crumble during cooling, unless the grain size is nano-scale (Namavar, 2007). FIB-SEM has shown that the tetragonal to monoclinic phase transformation causes extensive fracture, particularly along grain boundaries, as a consequence of hydro-thermal degradation (Gaillard et al, 2008;Keuper et al, 2013). Cracking is also apparent when using TEM to study the phase transformation in oxides formed during the oxidation of zirconium alloys (Bailey, 1964;Bossis, 2002;Ni et al, 2010).…”

Section: Development and Validationmentioning

confidence: 99%

“…In manufactured zirconia coatings, the tetragonal to monoclinic phase transformation is known to arrest cracks due to the dilatational expansion (Chevalier et al, 2009). However, it has also been linked to the problem of crack micro-branching (Kirchner and Gruver, 1981;Nono, 2005), and is a significant problem associated with hydro-thermal degradation (Gaillard et al, 2008;Keuper et al, 2013). with very few or no grain boundaries and defects in the surrounding oxide.…”

Section: Damage Analysismentioning

confidence: 99%

Peridynamic simulations of the tetragonal to monoclinic phase transformation in zirconium dioxide

Platt

Mella

DeMaio

et al. 2017

Computational Materials Science

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Whether present as a manufactured stabilised ceramic, or as an oxide layer on zirconium alloys, mechanical degradation in zirconia is influenced by the tetragonal to monoclinic phase transformation.Peridynamic theory was implemented within the Abaqus finite element framework to understand how the tetragonal to monoclinic phase transformation can itself cause fracture in zirconia. In 2D these simulations represent a single grain, transforming via an isometric dilational expansion, surrounded by a homogenous monoclinic oxide. The effect of transformation time, applied bi-axial pressure, and the fracture strain were assessed using the change in strain energy and the amount of damage in the oxide surrounding the transformed grain. Reducing the applied compressive stress or applying a tensile stress reduces the transformation strain energy. The introduction of a fracture strain leads to damage in the surrounding oxide region largely in the form of cracks, and reduces the transformation strain energy further by reducing the constraint on the transforming grain. The extent of the fracture, and reduction in constraint on the transformed grain, is more significant with the application of a biaxial tensile pressure.

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Assessment of ultrathin yttria-stabilized zirconia foils for biomedical applications

et al. 2015

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Bulk yttria-stabilized zirconia is a well-studied material with various applications, in particular for biomedical devices. Interestingly, it is now possible to obtain thin stand-alone sheets (40 lm thick) of this material. We present a preliminary study dealing with the aging of these foils to determine whether they would be suitable for implantable neurostimulator housing. Accelerated hydrothermal aging experiments were performed at 134°C and 2 bar. Various analyses of the material were carried out, especially by atomic force microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-visible-near-infrared spectroscopy. The results show that the foils maintain their integrity during simulated long-term in vivo experiments, which indicates that they are not prone to fast degradation. The observed monoclinic transformation initiates from the surface and propagates into the bulk, leading to two distinct observable parts within the sheet. The aged and the nonaged parts are separated by a limit almost linear and parallel to the surface. We also show that the micro-strains are not altered significantly after 5 h accelerated aging, and that the optical properties are not modified despite structural modifications. Although further work is needed, we have shown that foils of yttria-stabilized zirconia resist accelerated aging and are thus a promising material for the fabrication of ultrathin implantable devices.

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Direct evidence for continuous linear kinetics in the low-temperature degradation of Y-TZP

Cited by 65 publications

References 39 publications

Long-term stability of an injection-molded zirconia bone-level implant: A testing protocol considering aging kinetics and dynamic fatigue

Long-term stability of an injection-molded zirconia bone-level implant: A testing protocol considering aging kinetics and dynamic fatigue

Peridynamic simulations of the tetragonal to monoclinic phase transformation in zirconium dioxide

Assessment of ultrathin yttria-stabilized zirconia foils for biomedical applications

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