Effect of Precursors on Impregnation Behaviors of C/SiC Composites

doi:10.15541/jim20190541

Abstract

Abstract:

In order to investigate the influence of precursors on impregnation behaviors of C/SiC composites, C/SiC composites (C/SiC-0,C/SiC-Ⅰand C/SiC-Ⅱ) prepared with three different precursors (solid polycarbosilane, PCS(s)), liquid polycarbosilane PCS-Ⅰ(l) and PCS-Ⅱ(l)) were prepared via precursor infiltration and pyrolysis (PIP) method. Impregnation behaviors of different precursors were studied to mainly focuse on the combination of mechanical properties as well as microstructures of C/SiC composites with different PIP cycles. Results showed that C/SiC-Ⅰ composites exhibited the highest flexural strength of 336 MPa. The microstructures of C/SiC composites showed that the internal pores of C/SiC-0 composites were distributed between carbon fiber bundles, C/SiC-I composites were dense and the pores were evenly distributed. The pores of C/SiC-II composites were inside carbon fiber bundles and SiC matrix. Gel permeation chromatography (GPC) results showed that due to the difference of molecular weights of the impregnating solution, the macromolecules cannot impregnated into the carbon fiber bundles, which resulted in the lack of SiC matrix and degradation of mechanical properties for the composites after PIP cycles.

Key words: impregnation, solid polycarbosilane, liquid polycarbosilane, C/SiC composites

CLC Number:

TB332

ZHANG Bingyu,WANG ling,WANG Xiaomeng,QIU Haipeng. Effect of Precursors on Impregnation Behaviors of C/SiC Composites[J]. Journal of Inorganic Materials, 2020, 35(9): 1017-1022.

Figures/Tables 9

Table 1 Density and porosity of C/SiC composites prepared with different precursors

C/SiC composites	Precursors type	Density /(g·cm^-3)	Porosity/%
C/SiC-0	PCS(s)	1.99	5.18
C/SiC-Ⅰ	PCS-Ⅰ(l)	1.98	5.34
C/SiC-Ⅱ	PCS-Ⅱ(l)	1.81	6.12

Table 2 Molecular mass of different precursors

Precursors type	mn	mw	mp	mz
PCS(s)	1698	4813	6221	10951
PCS-Ⅰ(l)	1077	4051	2211	14695
PCS-Ⅱ(l)	4495	5735	3369	8010

Fig. 1 TGA curves of PCS pyrolysis in inert atmosphere

Table 3 Flexural strength and modulus of C/SiC composites prepared with different precursors

Specimen	Average flexural strength/MPa	Average flexural modulus/GPa
C/SiC-0	293	49.1
C/SiC-Ⅰ	336	53.8
C/SiC-Ⅱ	280	47.1

Fig. 2 Flexural strain-stress curves of C/SiC composites with different precursors

Fig. 3 SEM images of C/SiC composites after 1st cycle of PIP process (a) C/SiC-0; (b) C/SiC-Ⅰ; (c) C/SiC-Ⅱ. Insets are the corresponding enlarged images

Fig. 4 SEM images of C/SiC composites after 3nd cycle of PIP process (a) C/SiC-0; (b) C/SiC-Ⅰ; (c) C/SiC-Ⅱ

Fig. 5 SEM images of C/SiC composites after 10th cycle of PIP process (a) C/SiC-0; (b) C/SiC-Ⅰ; (c) C/SiC-Ⅱ. Insets are the corresponding enlarged images

Fig. 6 Schematic diagram of impregnation of C fiber preforms

References 15

[1]	ZHANG YONG, FENG DI, CHEN XI-CHUN. Development of properties and process on continuous fiber reinforced SiC composite. Material Review, 2005,19(3):63-66.
[2]	XIE WEI-JIE, QIU HAI-PENG, CHEN MING-WEI,et al. Influence of carbon fiber treatment on flexural properties of C/SiC composites. Solid State Phenomena, 2018,281:408-413. DOI URL
[3]	LI JUN-SHENG, ZHANG CHANG-RUI, LI BIN. Advances in boron nitride interphases in ceramic matrix composites. Material Review, 2011,25(9):14-21.
[4]	ZHANG YU-DI, ZHANG CHANG-RUI. Preparing of C_f/SiC composites by CVI-PIP and research on microstructure of composites. Journal of Materials Science & Engineering, 2004,22(5):657-659. DOI URL
[5]	ZOU SHI-QIN, ZHANG CHANG-RUI, ZHOU XIN-GUI,et al. The oxidation behaviors of C/SiC composites prepared by precursor infiltration pyrolysis process. Journal of National University of Defense Technology, 2005,27(5):107-112.
[6]	LI WEI, CHEN ZHAO-HUI. Evaluation of microstructure of C_f/SiC composite fabricated by precursor infiltration and pyrolysis. Rare Metal Material and Engingeering, 2007,36(1):611-614.
[7]	FENG QIAN, WANG WEN-QIANG, WANG ZHEN,et al. Microstructure analysis of SiC matrix composites reinforced by carbon fibers and SiC fibers. Research and Exploration in Laboratory, 2010,29(1):44-46.
[8]	YAN LIAN-SHENG, SONG MAI-LI, ZOU WU,et al. Effect of treatment at elevated temperature on the properties of carbon fibers and their composites. Aerospace Materials & Technology, 1998 (1):18-21.
[9]	JIAN KE, CHEN ZHAO-HUI, MA QING-SONG,et al. Application of boron in fabricating of 2D C_f/SiC composites by precursor pyrolysis. Rare Metal Material and Engingeering, 2006,35(2):5-8.
[10]	LI XU-DONG, EDIRISINGHE M J. Structural evaluation of polysilane-derived products: from amorphous to thermodynamically stable phases. Philosophical Magazine, 2003,84(7):647-671.
[11]	WYNNE K J, RICE R W. Ceramics via polymer pyrolysis. Annual Review Materials Science, 1984,14(1):297-334.
[12]	WANG XIU JUN. Precursors appllied for carbon fiber reinforced ceramic matrix composite. Beijing: Institute of Chemistry, Chinese Academy of Sciences, 2013.
[13]	LIU HAI-TAO, CHENG HAI-FENG, WANG JUN,et al. Characterization of mechanical properties of 2D-SiC_f/SiC composites fabricated by PIP process using multifilament composites. Rare Metal Material and Engingeering, 2009,38(10):1860-1863.
[14]	LIU SHAN-HUA. Research of Residual Thermal Stress and Matrix Cracking Stress for CMC-SiC with Hybrid Fibers. Xi'an: Northwestern Polytechnical University, 2014.
[15]	CHEN ZHAO-HUI. Precursor-derived Ceramic Matrix Composite, 1. Beijing: Science press, 2015: 1-252.