熔融纺丝过程优化制备细直径碳化硅纤维及其对力学性能的影响

doi:10.15541/jim20170512

摘要/Abstract

摘要：

强度、模量和柔顺性作为碳化硅(SiC)纤维重要的力学性能受到纤维直径大小的影响, 而制备工艺中的熔融纺丝过程对纤维直径起决定作用。本工作研究了纺丝温度、纺丝压力和卷绕速度对聚碳硅烷(Polycarbosilane, PCS)原纤维直径的影响, 分析了纺丝过程中纤维断裂的原因, 并初步探究了SiC纤维直径与力学性能的关系。结果表明, 在一定范围内降低纺丝温度、降低纺丝压力和提高卷绕速度均能显著减小原纤维的直径。在连续纺丝的前提下, 最优纺丝工艺下得到的PCS原纤维直径为13.5 μm。随着PCS纤维直径由18.3 μm减小至13.5 μm, SiC纤维直径则由13.8 μm减小至9.5 μm, 而SiC纤维的强度与模量分别由1.7、181 GPa提高至2.9、233 GPa, 强度分布更为集中, 柔顺性得到显著提高。

关键词: 聚碳硅烷, 熔融纺丝, SiC纤维, 直径

Abstract:

Strength, modulus and flexibility as three important mechanical properties for silicon carbide (SiC) fibers can be affected by diameter of SiC fiber, which is controled by specific melt-spinning process. In this study, effects of spinning temperature (T), spinning pressure (P) and winding speed (V) on diameter of polycarbosilane (PCS) fiber were studied. Mechanisms for the fiber breakage during spinning process was explored, and relationship between diameter and mechanical properties of SiC fiber was also analyzed. The results show that diameter of the PCS fiber is significantly reduced either by decreasing spinning temperature, or decreasing spinning pressure or increasing winding speed. The finest diameter of PCS fiber is 13.5 μm with the optimized spinning parameter T=337℃, P=0.2 MPa and V=240 m/min. After high-temperature pyrolysism, diameter of the obtained PCS fiber can be reduced from 13.8 μm to 9.5 μm. Meanwhile, tensile strength of SiC fibers increases from 1.7 GPa to 2.9 GPa, and Young’s modulus increases from 181 GPa to 233 Gpa, respectively, with less dispersed strength distnbution and enhanced flexibility.

Key words: polycarbosilane, melt-spinning, SiC fiber, diameter

中图分类号:

TQ174

王国栋, 宋永才. 熔融纺丝过程优化制备细直径碳化硅纤维及其对力学性能的影响[J]. 无机材料学报, 2018, 33(7): 721-727.

WANG Guo-Dong, SONG Yong-Cai. Enhancing Mechanical Property of SiC Fiber by Decreasing Fiber Diameter through a Modified Melt-spinning Process[J]. Journal of Inorganic Materials, 2018, 33(7): 721-727.

图/表 13

图1 PCS-1的GPC及FT-IR谱图

Fig. 1 GPC and FT-IR spectrum of PCS-1

图2 PCS-1的粘度随温度变化曲线

Fig. 2 Relationship between temperature and melt viscosity of PCS-1

图3 纺丝温度对PCS纤维直径的影响

Fig. 3 Influence of temperature on diameter of PCS fiber

图4 纺丝压力对PCS纤维直径的影响

Fig. 4 Influence of spinning pressure on diameter of PCS fiber

图5 卷绕速度对PCS纤维直径的影响

Fig. 5 Influence of winding speed on diameter of PCS fiber

表1 纺丝条件与纺丝结果

Table 1 Melting spinning conditions and result of spinning

Samples	Spinning temperature/℃	Winding speed /(m•min^-1)	Pressure /MPa	Continue spinning time/min	Diameter /μm
PCS_f-1	336	240	0.25	35.0	14.7
PCS_f-2	336	240	0.20	10.0	12.5
PCS_f-3	336	213	0.20	27.0	13.0
PCS_f-4	337	267	0.25	14.0	14.5
PCS_f-5	337	267	0.20	3.0	11.8
PCS_f-6	337	240	0.20	32.0	13.5
PCS_f-7	337	240	0.30	35.0	17.4
PCS_f-8	337	240	0.15	0.5	12.4
PCS_f-9	338	267	0.20	34.0	13.9
PCS_f-10	338	240	0.15	16.0	12.7

图6 PCSf-6纤维及PCSf-7纤维的光学照片

Fig. 6 Optical photos of PCSf-6 and PCSf-7

图7 纤维断裂过程示意图和纤维照片

Fig. 7 Illustrated process and photos of fiber breaking(a) Ductile drawing and curing zone; (b) Transient stable zone; (c) Brittle fracture zone

图8 断裂模式示意图

Fig. 8 Schematic diagram of breaking pattern

表2 不同直径SiC纤维的力学性能

Table 2 Mechanical properties of SiC fibers with different diameters

Samples	PCS fiber diameter/μm	SiC fiber diameter/μm	Strength /GPa	Modulus /GPa
SiC-1	13.5	9.5	2.9	233
SiC-2	16.0	10.7	2.4	210
SiC-3	17.4	12.1	1.8	191
SiC-4	18.3	13.8	1.7	181

图9 SiC-1的SEM照片

Fig. 9 SEM image of SiC-1

图10 不同直径SiC纤维拉伸强度的Weibull统计

Fig. 10 Weibull statistics of tensile strength of SiC fibers with different diameters

表3 不同直径SiC纤维Weibull参数

Table 3 Weibull parameters of SiC fibers with different diameters

Samples	SiC fiber diameter/μm	Weibull modulus	Scale parameter, σ₀/GPa	Related coefficient, R²
SiC-1	9.5	0.26	0.011	0.95
SiC-2	10.7	0.25	0.019	0.97
SiC-3	12.1	0.22	0.034	0.95
SiC-4	13.8	0.16	0.017	0.97

参考文献 18

[1]	BUNSELL A R, PIANT A.A review of the development of three generations of small diameter silicon carbide fibres.Journal of Materials Science, 2006, 41(3): 823-839.
[2]	YUAN QIN, SONG YONGCAI.Research and development of continuous SiC fibers and SiCf/SiC composites. Journal of Inorganic Materials, 2016, 31(11): 1157-1165.
[3]	NARISAWA M, IDESAKI A, KITANO S,et al.Use of blended precursors of poly(vinylsilane) in polycarbosilane for silicon carbide fiber synthesis with radiation curing.Journal of the American Ceramic Society, 2010, 82(4): 1045-1051.
[4]	XIAO HANNING, LIU JINGXIONG, GUO WENMING,et al.Technological state and industrial development of engineering ceramics.Materials for Mechanical Engineering, 2016, 40(6): 1-7.
[5]	WANG XIUFEI, HUANG QIZHONG, NING KEYAN, et al.Effects of siliconizing on graphitization degree of carbon fiber.Journal of Materials Engineering, 2007(1): 52-55.
[6]	NASLAIN R.Design, preparation and properties of non-oxide CMCs for application in engines and nuclear reactors: an overview.Composites Science and Technology, 2004, 64(2): 155-170.
[7]	CHU ZENGYONG, WANG YINGDE, CHENG HAIFENG,et al. Effects of defect types on the relationship between tensile strength and diameter of SiC fibers.Rare Metal Material and Engineering, 2008, 37(a01): 807-809.
[8]	YU YUXI, LI XIAODONG, CAO FENG, et al.Composition and structure of poly-derived aluminium-containing SiC fibers.Journal of Inorganic Materials, 2006, 21(1): 94-102.
[9]	YAJIMA S, OKAMURA K, HAYASHI J,et al.Synthesis of continuous SiC fibers with high tensile strength.Journal of the American Ceramic Society, 1976, 59(7/8): 324-327.
[10]	IDESAKI A, NARISAWA M, OKAMURA K,et al.Fine SiC fiber synthesized from organosilicon polymers: relationship between spinning temperature and melt viscosity of precursor polymers.Journal of Materials Science, 2001, 36(23): 5565-5569.
[11]	TANG MING, YU ZHAOJU, YU YUXI, et al. Preparation of silicon carbide fibers from the blend of solid and liquid polycarbosilanes.Journal of Materials Science, 2009, 44(6): 1633-1640.
[12]	TANG MING, YU ZHAOJU, LAN LIN,et al.Study of the silicon carbide fibers from the blend of solid and liquid polycarbosilanes.Journal of Functional Materials, 2012, 43(16): 2267-2272.
[13]	CHU ZENGYONG, LIU HUI, FENG CHUNXIANG, et al.Modulation of spinnable polycarbosilane with a high melting point via fractional precipitation.Journal of National University of Defense Technology, 2002, 24(1): 39-43.
[14]	LIU HUI, CHEN ZHENXING, YE HONGQI,et al.Kinetisc simulation on melt spinning of polycarbosilane.Jiangsu Chemical Industry, 2003, 31(4): 44-46.
[15]	LIU HUI, WANG YINGDE, FENG CHUNXIANG,et al.Study on rheological property of polycarbosilane.China Synthetic Fiber Industry, 2001, 24(5): 23-25.
[16]	金日光, 马秀清. 高聚物流变学.江西: 东华理工大学出版社, 2012: 374-381.
[17]	WEIBULL W.A statistical distribution function of wide applicability.Journal of Applied Mechanics, 1951, 13(2): 293-297.
[18]	BERGER M H, JEULIN D.Statistical analysis of the failure stresses of ceramic fibres: dependence of the Weibull parameters on the gauge length, diameter variation and fluctuation of defect density.Journal of Materials Science, 2003, 38(13): 2913-2923.