短碳纤维增强碳化硅基复合材料的制备与力学性能

doi:10.15541/jim20180578

摘要/Abstract

摘要：

利用注浆成型结合反应烧结的方法制备了高强度短碳纤维增强碳化硅基复合材料, 研究了分散剂(四甲基氢氧化铵)的含量和混料时间对浆料粘度的影响; 短碳纤维的体积分数、碳化硅粉的粒径对复合材料微观结构和力学性能的影响。结果表明, 添加0.1wt%的四甲基氢氧化铵得到的浆料粘度最低, 混料时间控制在6 h为佳。添加35vol%短碳纤维的复合材料的弯曲强度达到(412±47) MPa。由5 μm粒径碳化硅粉制备的复合材料的力学性能最佳, 其弯曲强度可达(387±40) MPa。将5与50 μm粒径的碳化硅粉进行2 : 1混合后得到的复合材料的力学性能优异, 弯曲强度可达(357±41) MPa。

关键词: C_sf/SiC复合材料, 注浆成型, 反应烧结

Abstract:

In this study, high-strength silicon carbide (SiC) matrix composites reinforced by short carbon fiber (C_sf) (SiC/C_sf) were fabricated by slip casting and reaction sintering. The effects of the dispersant (tetramethylammonium hydroxide, TMAH) content and mixing time on the viscosity of the slurry were investigated. In addition, the influences of the volume fraction of C_sf and particle size of SiC powder on the mechanical property were also studied. It is found that the viscosity of slurry with 0.1wt% TMAH is the lowest and the mixing time is preferably controlled at 6 h. The composites with 35vol% C_sf shows the highest flexural strength of (412±47) MPa. The composites with 5 μm SiC powder achieves the highest flexural strength of (387±40) MPa. Grain composition demonstrates that the sample prepared by a mixture of 5 and 50 μm SiC powder at a ratio of 2 to 1 shows relatively excellent mechanical properties with the flexural strength up to (357±41) MPa.

Key words: C_sf/SiC composites, slip casting, reaction sintering

中图分类号:

TQ174

孟祥玮,吴西士,裴兵兵,朱云洲,黄政仁. 短碳纤维增强碳化硅基复合材料的制备与力学性能[J]. 无机材料学报, 2019, 34(9): 1015-1020.

MENG Xiang-Wei,WU Xi-Shi,PEI Bing-Bing,ZHU Yun-Zhou,HUANG Zheng-Ren. Preparation and Mechanical Property of Short Carbon Fiber Reinforced Silicon Carbide Matrix Composites[J]. Journal of Inorganic Materials, 2019, 34(9): 1015-1020.

图/表 14

Table 1 Physical property of the carbon fiber (12KT300)

Item	Specification
Tensile strength	≥ 3.5 GPa
Density	1.75 g/cm³
Monofilament diameter	7 μm
Aspect ratio	2 : 1-8 : 1
Coefficient of linear expansion	-0.1 × 10^-6

Fig. 1 Viscosity-shear rate curves of slurries with different TMAH content

Fig. 2 Apparent porosity and bulk density of green body with different TMAH content

Fig. 3 SEM images of green bodies with different contents of TMAH: (a-d) 0.05wt%, 0.1wt%, 0.3wt%, 0.5wt%, respectively

Table 2 Effect of the mixing time on the composites

No.	Mixing time/h	Solid content/ %	Carbon fiber volume fraction/vol%	SiC particle size/μm	TMAH/wt%	PVP/ wt%
1	4	70	45	5	0.3	2
2	6	70	45	5	0.3	2
3	8	70	45	5	0.3	2

Fig. 4 Viscosity-shear curves of slurries with different mixing time and feeding modes

Fig. 5 Relationship between apparent porosity and mixing time (a), bulk density and mixing time (b) of slurries

Table 3 Physical and mechanical properties of composites with different short carbon fiber contents

Volume Fraction/%	Green body		Sintered bulk
Volume Fraction/%	Apparent porosity/%	Bulk density/ (g·cm^-3)	Apparent porosity/%	Bulk density/ (g·cm^-3)
30	(46.09±0.25)	(1.26±0.01)	(1.17±0.26)	(3.06±0.02)
35	(47.14±0.46)	(1.19±0.01)	(0.38±0.12)	(3.08±0.007)
40	(45.08±1.20)	(1.16±0.03)	(1.17±0.23)	(3.01±0.01)

Fig. 6 Variation of flexural strength of composites as a function of the carbon fiber volume fraction

Table 4 The bulk density and apparent porosity of green body and the sintered bulk containing SiC with different particle sizes。。

Particle size/μm	Green body		Sintered bulk
Particle size/μm	Apparent porosity/%	Bulk density/ (g·cm^-3)	Apparent porosity/%	Bulk density/ (g·cm^-3)
5	(44.61±0.49)	(1.26±0.01)	(0.95±0.62)	(3.01±0.02)
10	(43.88±1.05)	(1.28±0.02)	(1.10±0.48)	(2.99±0.02)
20	(42.29±2.30)	(1.32±0.06)	(2.03±1.13)	(2.96±0.04)
50	(40.46±0.07)	(1.35±0.004)	(2.20±1.72)	(2.99±0.07)

Fig. 7 Flexural strength of Csf/SiC composites containing SiC with different particle sizes

Fig. 8 SEM image of sintered composites containing SiC with different particle sizes: (a) 5 μm; (b) 10 μm; (c) 20 μm; (d) 50 μm

Table 5 Bulk density and apparent porosity of green body and sintered bulk with different grain compositions

Particle size/μm	Green body		Sintered bulk
Particle size/μm	Apparent porosity/%	Bulk density/ (g·cm^-3)	Apparent porosity/%	Bulk density/ (g·cm^-3)
50/10	(42.73±1.48)	(1.35±0.07)	(0.79±0.11)	(3.04±0.03)
10/5	(44.37±0.21)	(1.27±0.004)	(0.72±0.10)	(3.05±0.01)
20/5	(43.46±0.66)	(1.28±0.01)	(1.05±0.18)	(3.06±0.01)
50 : 5	(41.88±0.78)	(1.34±0.02)	(0.86±0.26)	(3.04±0.02)

Fig. 9 Flexural strength of composites with different grain compositions

参考文献 16

[1]	BECHSTEDT F, KÄCKELL P, ZYWIETZ A , et al. Polytypism and properties of silicon carbide. Phys. Status. Solidi. B, 1997,202(1):35-62.
[2]	LUTHRA K L . Some new perspectives on oxidation of silicon carbide and silicon nitride. J. Am. Ceram. Soc., 1991,74(5):1095-1103.
[3]	LAINE R M, BABONNEAU F . Preceramic polymer routes to silicon carbide. Chem. Mater., 1993,5(3):260-279.
[4]	SUYAMA S, KAMEDA T, ITOH Y ,et al. Development of high-strength reaction-sintered silicon carbide. Diam. Relat. Mater., 2003,12(3):1201-1204.
[5]	VERRILLI M J, OPILA E J, CALOMINO A ,et al. Effect of environment on the stress-supture behavior of a carbon-fiber-reinforced silicon carbide ceramic matrix composite. J. Am. Ceram. Soc., 2004,87(8):1536-1542.
[6]	VINCI A, ZOLI L, SCITI D . Influence of SiC content on the oxidation of carbon fibre reinforced ZrB₂/SiC composites at 1500 and 1650 ℃ in air. J. Eur. Ceram. Soc., 2018,38(11):3767-3776.
[7]	MARSHALL D B, OLIVER W C . Measurement of interfacial mechanical properties in fiber-reinforced ceramic composites. J. Am. Ceram. Soc., 1987,70(8):542-548.
[8]	QIANG X, LI H, ZHANG N ,et al. Oxidation resistance of SiC nanowires reinforced SiC coating prepared by a CVD process on SiC-coated C/C composites. Int. J. Appl. Ceram. Tec., 2018,15(5):1100-1109.
[9]	ZHU Y Z, HUANG Z R, DONG S M ,et al. Effect of active Al fillers on properties of PIP-derived SiC_f/SiC composites. J. Inorg. Mater., 2007,22(5):954-958.
[10]	GBADEYAN O, KRISHNAN K, MOHAN T P ,et al. Tribological, mechanical, and microstructural of multiwalled carbon nanotubes/ short carbon fiber epoxy composites. J. Tribol., 2017,140(2):022002.
[11]	CHEN L, YIN X, FAN X ,et al. Mechanical and electromagnetic shielding properties of carbon fiber reinforced silicon carbide matrix composites. Carbon, 2015,95:10-19.
[12]	HE F, LIU Y, TIAN Z ,et al. Carbon fiber/SiC composites modified SiC nanowires with improved strength and toughness. Mat. Sci. Eng. A-Struct., 2018,734:374-384.
[13]	HE X, GUO Y K, YU Z M ,et al. Study on microstructures and mechanical properties of short-carbon-fiber-reinforced SiC composites prepared by hot-pressing. Mat. Sci. Eng. A-Struct., 2009,527(1):334-338.
[14]	CHENG Y, LIU C, HU P ,et al. Using PyC coated short chopped carbon fiber to tackle the dilemma between toughness and strength of ZrC-SiC. Ceram. Int., 2018,45(1):503-509.
[15]	TANG C, LI T H, BAI Y H ,et al. Two-step method to deposit ZrO₂ coating on carbon fiber: preparation, characterization, and performance in SiC composites. Ceram. Int., 2018,44(10):11812-11819.
[16]	LI F, HUA Y, QU C B ,et al. Effectively enhanced mechanical properties of injection molded short carbon fiber reinforced polyethersulfone composites by phenol-formaldehyde resin sizing. Compos. Part B-Eng., 2018,139:216-226.