Articles
All articles | Recent articles
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.
Download Full Article (PDF)
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).
Copyright
© 2010 Göller Verlag