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Properties of Injection Moulded Alumina-Toughened Zirconia
F. Kern, R. Gadow
University of Stuttgart, Institute for Manufacturing Technologies of Ceramic Components and Composites, Allmandring 7 b, D-70569 Stuttgart, Germany
received May 26, 2010, received in revised form July 05, 2010, accepted October 06, 2010
Vol. 2, No. 1, Pages 47-54 DOI: 10.4416/JCST2010-00019
Abstract
Alumina-toughened zirconia (ATZ) materials are suitable materials for a variety of biomedical applications owing to their high strength, toughness and hydrothermal stability. The prospect of being able to offer ceramic implants to a broader group of patients requires a more cost-efficient near-net-shape manufacturing approach. Small and complex-shaped components can be efficiently mass-produced by means of ceramic injection moulding (CIM) with high surface quality and low dimensional tolerances. Compared to the state-of-the-art cold and hot isostatic pressing cycles commonly used for implant production, CIM technology does suffer from lower microstructural quality. During the thermally and rheologically transient mould-filling process, inevitably a certain number of defects are induced by flow textures, weld lines and micro-segregation. A higher level of toughness is therefore beneficial to keep strength and damage tolerance on a sufficiently high level. In order to improve thetoughness of ATZ, in-situ platelet reinforcement with strontium hexaaluminate precipitates was introduced. The influence on processing behaviour, strength and toughness of as-manufactured and final-machined platelet-containing and platelet-free 2.5Y-TZP/15 vol% alumina composites was investigated. Platelets improve the mechanical properties. Weibull statistics show that platelet addition leads to drastic improvements in reliability.
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Keywords
ATZ, CIM, platelets, Weibull statistics, toughening
References
1 Chevalier, J., Gremillard, L., Virkar, A.V., Clarke, D.R.: The Tetragonal-Monoclinic Transformation in Zirconia: Lessons Learned and Future Trends, J. Am. Ceram. Soc., 92 [9], 1901-1920, (2009).
2 Hannink, R., Kelly, P., Muddle, B.: Transformation Toughening in Zirconia-Containing Ceramics, J. Am. Ceram. Soc., 83 [3], 461- 87, (2000).
3 Chevalier, J., Cales, B., Drouin, J.M.: Low-Temperature Aging of Y-TZP Ceramics, J. Am. Ceram. Soc., 82 [8] 2150-4, (1999).
4 Chevalier, J., Gremillard, L., Deville, S.: Low-temperature degradation of zirconia and implications for biomedical implants, Annu. Rev. Mater. Res. (2007) 37:1-32.
5 Tsubakino, H., Sonoda, K., Nozato, R.: Martensite transformation behaviour during isothermal ageing in partially stabilized zirconia with and without alumina addition, J. Mater. Sci. Lett., 12, 196-8, 1993.
6 Ross, I.M., Rainforth, W.M., McComb D.W., Scott, A.J., Brydson, R.: The role of trace additions of alumina to yttria-tetragonal zirconia polycrystals (Y-TZP), Scripta Materialia, 45 , 6, 653-660, (2001).
7 Tsukuma, K., Ueda, K.: Strength and fracture toughness of isostatically hot-pressed composites of Al2O3 and Y2O3 partially stabilized ZrO2, J. Am. Ceram. Soc., 68 [1], C-4-C-5, (1985).
8 Cutler, R.A., Mayhew, R.J., Prettyman, K.M. and Virkar, A.V.: High-Toughness Ce-TZP/AI2O3 Ceramics with Improved Hardness and Strength, J. Am. Ceram. Soc., 74 [I] 179-86, (1991).
9 Miura, M., Hongoh, H., Yogo, T., Hirano, S., Fujii, T.: Formation of plate-like lanthanum-β-Aluminate crystal in Ce-TZP matrix, J. Mat. Sci. 29, 262-268, (1994).
10 Burger, W., Richter, H.G.: High strength and toughness alumina matrix composites by transformation toughening and in situ platelet reinforcement (ZPTA) – the new generation of bioceramics, Key Eng. Mat., 192-195 , 545-548, (2001).
11 Kern, F., Gadow, R.: Extrusion and Injection Molding of Ceramic Micro- and Nanocomposites, Int. J. Mat. Forming, Vol. 2, Suppl. 1, 609-612, (2009).
12 Swain, M.V, Rose, L.R.F.: Strength limitations in zirconia toughened ceramics, J. Am. Ceram. Soc., 69 [7] 511-18, (1986).
13 Casellas, D., Alcala, J., Llanes, L., Anglada, M.: Fracture variability and R-curve behaviour in yttria-stabilized zirconia ceramics, J. Mat. Sci., 36 3011 – 3025, (2001).
14 Kern, F., El-Ezz, M.A.; Gadow, R.: Thermoplastic Ceramic Injection Molding of Zirconia-Toughened-Alumina Components, in: ICACC34 Daytona Beach, USA, 2010.
15 Opfermann, J., Blumm, J., Emmerich W.-D.: Simulation of the sintering behavior of a ceramic green body using advanced thermokinetic analysis, Thermochimica Acta, 318, 213-220, (1998).
16 Niihara, K.: A fracture mechanics analysis of indentation-induced Palmqvist crack in ceramics, J. Mat. Sci. Let., 2, 221-223, (1983).
17 Anstis, G. R., Chantikul, P., Lawn, B. R. and Marshall, D. B. A.: A critical evaluation of indentation techniques for measuring fracture toughness. I. Direct crack measurements, J. Am. Ceram. Soc., 64, 533-538, (1981).
18 Chantikul, P., Anstis, G. R., Lawn, B. R. and Marshall, D. B. A.: A critical evaluation of indentation techniques for measuring fracture toughness. II. Strength method, J. Am. Ceram. Soc., 64, 539-543, (1981).
19 Toraya, H., Yoshimura, M., Somiya, S.: Calibration Curve for Quantitative Analysis of the Monoclinic-Tetragonal ZrO2 System by X-Ray Diffraction, J. Am. Ceram. Soc., 67, 6, C119-121, (1984).
20 Chen, M., Hallstedt, B., Gauckler, L.J.: Thermodynamic modeling of the ZrO2-YO1.5 system, Solid State Ionics 170, 255-274, (2004).
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