Alumina nanocomposites from powder–alkoxide mixtures

Schehl, Martín; Díaz, Luis A.; Torrecillas, Ramón

doi:10.1016/s1359-6454(01)00413-x

Cited by 120 publications

(94 citation statements)

References 25 publications

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“…In this investigation, a major research effort was concentrated in a new colloidal processing route of alumina-zirconia composites [25]. This processing route consists in doping a stable suspension of the above mentioned alumina powder in absolute ethanol (99.97%) by dropwise addition of a diluted (2/3 vol% Zr alkoxide, 1/3 vol% ethanol absolute) zirconium alkoxide.…”

Section: Methodsmentioning

confidence: 99%

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: Methodsmentioning

confidence: 99%

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

et al. 2002

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“…ZTA batches with the same zirconia proportion were also processed through a modified colloidal processing route developed by Schehl et al 30 A composition with 7.5 vol% ZrO 2 was additionally processed. Stable suspensions of the above-mentioned alumina powder in absolute ethanol (99.97%) were doped by dropwise addition of a diluted (2/3 (vol%) zirconium alkoxide solution, 1/3 (vol%) ethanol absolute) zirconium alkoxide solution (zirconium(IV) propoxide 70 wt% solution in 1-propanol, Aldrich Chemical, Milwaukee, WI).…”

Section: (1) Materials Processingmentioning

confidence: 99%

Slow‐Crack‐Growth Behavior of Zirconia‐Toughened Alumina Ceramics Processed by Different Methods

Aza

Chevalier

Fantozzi

et al. 2003

Journal of the American Ceramic Society

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A study of slow-crack propagation in zirconia-toughened alumina (ZTA) ceramics is presented. Different ZTA composites, using either unstabilized or yttria-stabilized zirconia, have been tested. The materials were prepared in the range 0 -15 vol% ZrO 2 , using two processing methods: powder mixing and a modified colloidal route. Crack propagation tests have been conducted for crack velocities from 10 ؊12 to 10 ؊2 m/s by means of a double-torsion method. The influence of the processing conditions and compositions on the microstructures and the effect of these microstructures on the slow-crackgrowth behavior have been studied. The option that these composites may offer in terms of the lifetime of ceramic joint prostheses is discussed.

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“…This processing route was described in detail elsewhere. 18 It consists of doping a stable suspension of a high-purity alumina powder a-Al 2 O 3 499.9 wt% (Condea HPA 0.5, Ceralox Division, Tucson, AZ), with an average particle size of 0.45 mm and a surface area of 10 m 2 /g (values given by the supplier), in absolute ethanol (99.97%) by dropwise addition of a diluted (2/3 vol% Zr alkoxide, 1/3 vol% absolute ethanol) zirconium alkoxide (Aldrich zirconium IV propoxide, 70 wt% solution in 1-propanol, Sigma-Aldrich, Madrid, Spain). In the present work, a low amount of zirconia precursor was added, to obtain composites with only 1.7 vol% (2.5 wt%) zirconia nanoparticles.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, innovative processing routes have been used to obtain very fine microstructures with a narrow distribution of zirconia particles homogeneously dispersed in the alumina matrix at grain boundaries. [14][15][16][17][18][19] This leads to a high portion of tetragonal phase retained after sintering with the ability to transform under applied stress. 20 Thomsen and Karihaloo 21 have calculated, using a mathematical optimization procedure, that the volume fraction of the transformable phase in the near-surface region for transformation-toughened ceramics should be in the range from 3% to 10% in order to avoid excessive surface uplift.…”

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confidence: 99%

Alumina/Zirconia Micro/Nanocomposites: A New Material for Biomedical Applications With Superior Sliding Wear Resistance

Bartolomé

Aza

Martı́n

et al. 2007

Journal of the American Ceramic Society

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In the present investigation, the sliding wear behavior is described for Al 2 O 3 /ZrO 2 micro/nanocomposites and monolithic alumina of similar grain size under defined conditions of a constant sliding speed and different loads (20-150 N). Nano ZrO 2 particles (1.7 vol%) were observed uniformly distributing throughout the composites, and most of them were located within the matrix alumina grains. The wear rate of the alumina and the micro/nanocomposites increased as the contact load increased and a clear transition in friction and wear behavior was observed in both materials. However, the nanocomposite wear resistance at low contact loads was one order of magnitude higher than that of the alumina. In the severe regime, no difference was observed among the materials. The low wear rate (10 À7 mm 3 . (N . m) À1) along with low pullout indicates higher wear resistance of micro/nanocomposites in the mild regime compared with monolithic alumina. Based on the morphological observation of worn surfaces by scanning electron microscope and on residual stress analysis performed by neutron diffraction, some wear mechanisms of Al 2 O 3 -ZrO 2 micro/nanocomposites are proposed. The high wear resistance of the nanocomposites is discussed in terms of fracture resistance properties and residual stress. Improvements in mechanical and tribological properties of these composites make them promising candidates for biomedical applications.

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Alumina nanocomposites from powder–alkoxide mixtures

Cited by 120 publications

References 25 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

Slow‐Crack‐Growth Behavior of Zirconia‐Toughened Alumina Ceramics Processed by Different Methods

Alumina/Zirconia Micro/Nanocomposites: A New Material for Biomedical Applications With Superior Sliding Wear Resistance

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