KJ Ceramics 31

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Detailed Program

Paper Number : ST-O14

Time Frame : 16:10~16:30

Presentation Date : Friday, 28, November

Session Name : Structual Ceramics & Refractory materials

Session Chair 1# : Do-kyung Kim

Session Chair 2# : Masaki Narisawa

Erosion Resistance and Degradation of Various SiC/SiC Composites

Min-Soo SUH

Korea Institute of Energy Research

Keywords: Ceramic, Silicon carbide (SiC), Composite, Fiber reinforcement, Chemical vapor infiltration, Liquid pressure sintering, Erosion

SiC fiber-reinforced SiC matrix composite is candidate material for utmost severe environment due to their promising mechanical properties under the elevated temperature. Ablation resistant and erosion resistant are of significant importance in the field of aerospace application. Those mechanical characteristics have to be considered to improve the overall performance by developing the fabrication route.
This study investigate erosive wear behavior of various SiC/SiC composites manufactured by different fabrication routes, especially for the liquid pressure sintering (LPS) and chemical vapor infiltration (CVI) route. The fabrication characteristics shows that Tyranno SA grade SiC fibers were adopted with the pyrolytic carbon (PyC) interface and laminated as cross-ply fiber structure. For the LPS-P route, the phenolic resin interfaced were applied on Tyranno AG grade fibers, due to the volumetric shrinkage whilst the sintering. After erosive wear test, the material degradation mechanisms are unearthed primarily by the microscopic observation, and illustrated for each of composite material. The results show that the porosity seems to be one of the crucial material property when facing the erosion damage. In case of near-stoichiometric SiC/SiC composite fabricated by CVI (chemical vapor infiltration) route, particle bombardment cause severe fragment and damage. The dominant mechanism was that the high-applied flexural stresses resulted from the macro-sized pores inherent in the CVI composites only brings the partial support to upper layer. In the opposite, relatively low flexural stress was applied that the high densified LPS (liquid pressure sintering) SiC/SiC composite only contains micro-sized pores, and sufficiently gives the full support when the particle bombardment took place. The optimal fabrication conditions were characterized for LPS route, which shows high erosion resistant. The followings have to be concerned for manufacturing high performance SiC/SiC composite under harsh erosive environment: high volume fraction of matrix, high strength of matrix, high bonding strength of each constituent, and the coating of PyC interface.

References:

[1] M.S. Suh, T. Hinoki, and A. Kohyama, Tribol. Lett. 41 (2011) 503-513.
[2] S.R. Choi, J. Am. Ceram. Soc., 91(9) 2963–2968, (2008)

Acknowledgements :

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