Improved Precision Casting of Titanium Alloys Using Calcium Zirconate Moulds

Lisa Freitag1, Christos G. Aneziris1, Florian Bulling2, Ulrich E. Klotz2, Stefan Schafföner3

1 Institute of Ceramic, Glass and Construction Materials,TU Bergakademie Freiberg, 09596 Freiberg/Germany
2 Fem Research Institute for Precious Metals and Metals Chemistry, 73535 Schwäbisch Gmünd/Germany
3 Department of Materials Science and Engineering, 97 North Eagleville Road, Storrs CT 06269/USA


Volume 11, Issue 2, Pages 76 - 82


The main challenges of titanium investment casting are the high melting temperature and the extreme reactivity of the melt. Therefore, a new ceramic material for crucibles and moulds based on calcium zirconate (CaZrO3) is under development. However, the quality of titanium cast parts is not only determined by the interface reaction with the mould, but also by the surface quality and the reproduced shape details. The mould production by dip-coating is state-of-the-art. In order to further improve the precision of cast parts, calcium zirconate (CaZrO3) coatings were manufactured via the replica technique, enabling functional coatings for titanium casting moulds by spraying and centrifuging [1]. Moreover, casting trials investigated the corrosion resistance of CaZrO3 moulds, which were compared to a commercially available system containing silica. CaZrO3 showed a very weak reaction, indicated by small oxygen contents and thereby low surface hardness of the titanium cast parts [2].


precision casting, titanium, coating


[1] Freitag, L.; et al: Functional coatings for titanium casting molds using the replica technique. J. Europ. Ceram. Soc. 38 (2018) 4560–4567 [2] Bulling, F.; et al.: Investment casting of titanium alloys with calcium zirconate moulds and crucibles. 61st Int. Coll. on Refractories 2018, Aachen, 27.–26.09.2018 [3] Beeley, P.R.; Smart, R.F. (eds.): Investment casting. The Institute of Materials, London 1995 [4] Frueh, C.; et al.: Attempts to develop a ceramic mould for titanium casting – a review. Int. J. Cast Met. Res. 9 (1996) 233–239 [5] Kim, S.K.; et al.: Investment casting of titanium alloys with CaO crucible and CaZrO3 mold. Hoboken, NJ, 2001, 251–260, http://dx.doi. org/10.1002/9781118787922.ch23 [6] Klotz, U.E.; Heiss, T.: Evaluation of crucible and investment materials for lost wax investment casting of Ti and NiTi alloys. Int. J. Cast Met. Res. 27 (2014) 341–348 [7] Schafföner, S.; et al.: Investigating the corrosion resistance of calcium zirconate in contact with titanium alloy melts. J. Europ. Ceram. Soc. 35 (2015) 259–266 [8] Freitag, L.; et al.: Silica-free investment casting molds based on calcium zirconate. Ceram. Int. 43 (2017) 6807–6814 [9] Schwartzwalder, K.; Somers, H.; Somers, A.V.: Method of making porous ceramic articles, Patent US 3 090 094, 1963 [10] Voigt, C.; et al.: Investigations of reticulated porous alumina foam ceramics based on different coating techniques with the aid of µCT and statistical characteristics. Ceram. Int. 39 (2013) 2415–2422 [11] Reed, J.S.: Principles of ceramic processing, 2nd ed., New York, NY, 1995 [12] Tracton, A.A. (ed.): Coatings technology handbook. 3rd ed., Taylor & Francis Group, 2006 [13] Mezger, T.: The rheology handbook. 3rd ed., Hannover 2011


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