Process Development for the Ceramic Injection Molding of Oxide Chopped Fiber Reinforced Aluminum Oxide

Abstract:

In this study, it was tried to develop a process chain for ceramic injection molding of Al₂O₃-chopped-fiber reinforced oxide-ceramic-matrix-composite. The feedstocks are compounded at 50 Vol. % filling degree of solid (Al₂O₃ μ-powder (Taimei Chemicals Co. Ltd.) and 3,2 mm chopped fibers (3M)), in which fiber content varies from 0 Vol. % to 100 Vol. %. As binder system, PE + Paraffin Wax + Stearic Acid are used. The ingredients are compounded in a kneader (Brabender) at 125°C and after the viscosity measurement in the high pressure capillary rheometer at 160°C and certain shear rates, the feedstock is injection molded (Battenfeld) at 160°C, which is followed by debinding process, including chemical (in n-Hexane) and thermal steps, and 2h sintering at different temperatures. Flow paths in the machinery parts, rheological properties of binding system, fiber content and the fiber orientation have significant effect on the flow behavior of the feedstock, fiber -orientation, -distribution & -length, which are crucial to understand the properties of end-parts like mechanical reinforcement of the fibers. The fibers in the sintered parts are ca. 200 μm in average length. The fibers in the feedstock show different orientations depending on the part-geometry and the green bodies have different densities depending on sintering temperature, amount of dispersant and fiber orientation.

• Periodical: Key Engineering Materials (Volume 742)
• Pages: 231-237
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.742.231
• Online since: July 2017
• Authors: Metin Tueluemen*, Thomas Hanemann, Michael J. Hoffmann, Rainer Oberacker, Volker Piotter
• Keywords: Ceramic Matrix Composite (CMC), Fiber Orientation, Micro Injection Molding, Oxide Ceramics, Oxide Fibers, Sintering

References

[1] K. Chawla, Interface Mechanics and Toughness, in: W. Krenkel, Ceramic Matrix Composites, 2nd edition, 2003, pp.291-354.

DOI: 10.1007/978-1-4615-1029-1_9

[2] J.R. Strife, J.E. Sheehan, Ceramic Coatings for Carbon-Carbon Composites, in: American Ceramic Society Bulletin 67 (2), 02 (1988).

[3] W. Krenkel, M. Schmücker, P. Mechnich, All-Oxide Ceramic Matrix Composites with Porous Matrices, in: W. Krenkel, Ceramic Matrix Composites - Fiber Reinforced Ceramics and their Applications, 2008, pp.205-227.

DOI: 10.1002/9783527622412

[4] R. Heldele, Entwicklung und Charakterisierung von Formmassen für das Mikropulverspritzgießen, Freiburg im Breisgau, (2008).