Ceramic Steel?

Garvie, R. C.; Hannink, R. H. J.; Pascoe, R. T.

doi:10.1007/978-94-009-0741-6_14

Cited by 285 publications

(362 citation statements)

References 9 publications

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“…The high toughness of zirconia ceramics is attributed to the stress induced phase transformation of metastable tetragonal grains towards the monoclinic symmetry ahead of a propagating crack, leading to an increase of the work of fracture [28]. This phenomenon of transformation toughening relies on the volume expansion, 3-5%, and shear strain E7% developed when tetragonal zirconia transforms to the monoclinic form [29].…”

Section: Resultsmentioning

confidence: 99%

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Crack growth resistance of alumina, zirconia and zirconia toughened alumina ceramics for joint prostheses

et al. 2002

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Mono-phase bio-ceramics (alumina and zirconia) are widely used as femoral heads in total hip replacements (THR) as an alternative to metal devices. Unfortunately, the orthopaedic community reports significant in-vivo failures. Material scientists are already familiar with composites like alumina-zirconia. Since both are biocompatible, this could prove to be a new approach to implants. This paper deals with a new generation of alumina-zirconia nano-composites having a high resistance to crack propagation, and as a consequence may offer the option to improve lifetime and reliability of ceramic joint prostheses. The reliability of the above mentioned three bio-ceramics (alumina, zirconia and zirconia toughened alumina) for THR components is analysed based on the study of their slow crack-growth behaviour. The influence of the processing conditions on the microstructure development, of the zirconia toughened alumina composites and the effect of these microstructures, on its mechanical properties, are discussed. r

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Section: Resultsmentioning

confidence: 99%

“…The stabilisation of tetragonal phase is thought to arise from a combination of surface energy effects, constraints of the rigid matrix and stabilising oxide additions, e.g. yttria [28]. Transformation can occur locally once the constraints are removed, in this case when the crack propagates.…”

Section: Resultsmentioning

confidence: 99%

Crack growth resistance of alumina, zirconia and zirconia toughened alumina ceramics for joint prostheses

et al. 2002

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“…[1][2][3] Monoclinic zirconia exists below a temperature of 1170 C and is the weakest of the 3 allotropes. Tetragonal zirconia occurs within the range of 1170 C to 2370 C, while cubic zirconia is found at temperatures higher than 2370 C.…”

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confidence: 99%

“…Zirconia has high flexural strength and fracture toughness compared with other ceramics and can be used to replace metal frameworks in crowns and fixed dental prostheses. [1][2][3] Ahead of a crack tip, zirconia can undergo transformation toughening by transforming the tetragonal zirconia into monoclinic zirconia. Monoclinic zirconia is less dense than tetragonal zirconia because of a resultant expansion of approximately 4%.…”

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Effect of polishing procedures and hydrothermal aging on wear characteristics and phase transformation of zirconium dioxide

Bartolo

Cassar

Husain

et al. 2017

The Journal of Prosthetic Dentistry

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Statement of problem. Yttria-stabilized zirconia used for the fabrication of crowns and fixed\ud \ud prostheses may require intraoral adjustments after placement and cementation. Grinding and\ud \ud polishing methods may result in changes in the surface characteristics of zirconia.\ud \ud Purpose. The purpose of this in vitro study was to assess the effect of polishing procedures on\ud \ud surface roughness, topographical and phase changes of zirconia, and wear of the opposing dentition.\ud \ud Material and methods. Presintered and precut yttria-stabilized zirconia specimens (10×10×1 mm)\ud \ud were divided into 4 groups (control, Intensiv, Shofu, 3M ESPE) depending on the polishing method\ud \ud used to prepare the specimens. All tests were carried out in triplicate. The specimens were polished\ud \ud depending on the polishing regimen, while the control was left untreated. The specimens were\ud \ud thermocycled for 3000 cycles, with a temperature range of 5C to 55C. The surface roughness,\ud \ud elemental, and phase changes caused by polishing before and after thermocycling were assessed\ud \ud with surface profilometry, energy-dispersive spectroscopy, and X-ray diffraction analysis. The wear on\ud \ud antagonist steatite balls was also measured after mastication simulation. Statistical analysis was\ud \ud performed using 1-way ANOVA and the Tukey post hoc test to perform multiple comparison tests (a=.05).\ud \ud Results. The polishing procedures increased surface roughness (Ra) of yttria-stabilized zirconia from\ud \ud 0.52 for the control specimen to 0.73 for Intensiv, 0.70 for Shofu, and 0.70 for 3M ESPE (P<.05), which\ud \ud was reduced by thermocycling to 0.44 (control), 0.58 (Intensiv), and 0.58 (Shofu) (P<.001), while\ud \ud roughness remained unchanged for 3M ESPE specimens (0.75; P=.452). The deposition of aluminum\ud \ud when using Shofu abrasives and nickel in Intensiv was demonstrated. Phase changes were observed\ud \ud on the zirconia surface with formation of the monoclinic phase in all polishing methods. Specimen\ud \ud aging enhanced the surface phase changes and also induced compressive stresses in zirconia\ud \ud polished with Intensiv. The different polishing protocols did not affect the wear to the antagonist (P>.05).\ud \ud Conclusions. Polishing zirconia increased surface roughness and led to surface phase changes, but\ud \ud wear to the antagonist was not affected.peer-reviewe

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“…La literatura científica [1][2][3] ha descrito detalladamente algunos de los factores relevantes, tales como la cantidad y naturaleza de los elementos estabilizantes, el tamaño de grano o la presencia de tensiones residuales. Sin embargo, una de las limitaciones que presentan los materiales cerámicos de circona, de cara a su aplicación industrial es la degradación ambiental.…”

Section: Introductionunclassified

Degradación ambiental de las propiedades mecánicas de fibras monocristalinas de circona dopada con erbia

Pastor¹,

Ridruejo²,

Llorca³

et al. 2007

Bol. Soc. Esp. Ceram. Vidr.

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Partiendo de fibras monocristalinas de ZrO 2 (Er 2 O 3 ) tetragonal fabricadas por un procedimiento de fusión zonal con láser (LHFZ), se efectuaron ensayos de flexión en los que se medía la resistencia mecánica en función de la temperatura (25 a 800 ºC) y el medio (aire o agua). Los ensayos fueron realizados a distintas velocidades con objeto de establecer la susceptibilidad a las condiciones ambientales. La susceptibilidad ambiental de la ZrO 2 (Y 2 O 3 ) se había asociado siempre a la desestabilización de la fase tetragonal, pero el análisis de las superficies de fractura mediante microscopía electrónica de barrido y espectroscopia Raman confocal muestran una ausencia completa de fase monoclínica en las superficies de fractura de las fibras. Esta ausencia, junto con los ensayos complementarios sobre fibras sometidas a tratamientos de recocido para eliminar las tensiones residuales provenientes del procesado, indican que el crecimiento subcrítico de grieta se debe a un mecanismo de corrosión bajo tensión.Palabras clave: circona, erbia, estructura tetragonal, susceptibilidad al ambiente, crecimiento subcrítico de grieta, corrosión bajo tensión. Environmental degradation of the mechanical properties of single-crystal erbia-doped zircona fibersThe flexure strength of tetragonal ZrO 2 (Er 2 O 3 ) single-crystal monofilaments manufactured by the laser-heated floating zone method was measured as a function of the environment (air vs. water) and temperature (from 25 to 800ºC) at loading rates spanning three orders of magnitude to ascertain their susceptibility to the environmental conditions. These mechanical tests were completed with parallel tests on fully-annealed monofilaments (to relieve the thermal residual stresses induced during growth) and by detailed analysis of the fracture surfaces using scanning electron microscopy and micro-Raman spectroscopy. While environmental susceptibility of ZrO 2 (Y 2 O 3 ) in previous investigations was always associated with the destabilization of the tetragonal phase, monoclinic phase was not detected on the fracture surfaces of the ZrO 2 (Er 2 O 3 ) monofilaments and it was concluded that slow crack growth in this material at high temperature or immersed in water was due to stress-corrosion cracking.Keywords: zircona, erbia, tetragonal structure, environmental susceptibility, slow crack growth, stress-corrosion cracking INTRODUCCIóNLa importancia de la circona como material estructural estriba principalmente en la capacidad de aumentar su tenacidad mediante la transformación de la fase tetragonal -metaestable-en fase monoclínica cuando en el entorno de la punta de la grieta se supera un determinado umbral de tensión. La literatura científica [1-3] ha descrito detalladamente algunos de los factores relevantes, tales como la cantidad y naturaleza de los elementos estabilizantes, el tamaño de grano o la presencia de tensiones residuales. Sin embargo, una de las limitaciones que presentan los materiales cerámicos de circona, de cara a su aplicación industrial es la degradación amb...

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Ceramic Steel?

Cited by 285 publications

References 9 publications

Crack growth resistance of alumina, zirconia and zirconia toughened alumina ceramics for joint prostheses

Crack growth resistance of alumina, zirconia and zirconia toughened alumina ceramics for joint prostheses

Effect of polishing procedures and hydrothermal aging on wear characteristics and phase transformation of zirconium dioxide

Degradación ambiental de las propiedades mecánicas de fibras monocristalinas de circona dopada con erbia

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