Advanced SiC/SiC Composites by NITE Process

Cera-NITE®

Product information

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Cera-NITE: Advanced SiC/SiC Composites by NITE Process

Cera-NITE is the first generation high performance advanced SiC/SiC composite material products based on the NITE Nano-Infiltration and Transient Eutectic Phase) Process, invented and patented by Professor A. Kohyama and his research group at Kyoto University.

As the well known SiC/SiC Composite material fabrication processes, PIP (Polymer Impregnation and Pyrolysis) RS/MI Reaction Sintering/Melt Infiltration) and CVI (Chemical Vapor Infiltration) can be applied. However, as shown in Fig.1, inter-fiber bundle pores, matrix micro-cracks and/or micro-segregation of impurities causes degradation under severe environments, such as ultra-high temperature, radiation environments.

Only Cera-NITE, with highly dense SiC matrix and very limited porosity, can provide excellent gas tightness and stability of many properties under severe environments.

PIP
RS/MI

CVI
Cera-NITE

(Fig.1 : Difference in microstructure on different fabrication processes;
Excellence of Cera-NITE)

TEM microstructure of Cera-NITE

(Fig.2 : TEM microstructure of Cera-NITE)

Cera-NITE uses highly crystalized near stoichiometry SiC fiber, Tyranno-SA. The production of Cef-NITE (Tyranno-SA grade SiC fibers produced under the licensing of their patents) is now under preparation and Cef-NITE will be available from early 2007 and will be used as reinforcement of Cera-NITE. SiC matrix is introduced using a few tens of nm level nano-SiC powders. As shown in Fig. 2, highly dense, very low porosity SiC matrix (grain size is very similar with that of fibers) is formed inter- and intra-fiber bundles. Carbon coating is used as fiber-matrix interfacial layer. Other options are available including C/SiC multi-layers. Continuous coating line is under development and this process may improve total properties including uniformity and reduction of intra-bundle porosity.