聚铝碳硅烷先驱体的组成结构调控及转化碳化硅陶瓷研究

doi:10.15541/jim20260301

摘要/Abstract

摘要： 聚铝碳硅烷(PACS)先驱体是制备耐高温碳化硅(SiC)纤维的关键原料。针对传统“两步法”高温裂解合成PACS先驱体存在工艺复杂、组成与结构调控难等技术问题,本研究提出“一步法”常压裂解合成路线,以聚二甲基硅烷(PDMS)和乙酰丙酮铝(Al(AcAc)₃)为原料,系统开展了PACS先驱体合成、组成结构调控、陶瓷化转变过程及SiC陶瓷产物组成结构等研究。研究结果表明,通过控制原料中Al(AcAc)₃的质量分数(0~4%),可以实现先驱体中Al元素质量分数和数均分子量在0.07%~0.47%和1909~4302范围内的有效调控。当Al(AcAc)₃含量为2%时,所得PACS-2先驱体软化点为192.5 ℃,数均分子量为4302。“一步法”裂解合成PACS的反应机理为：PDMS在450 ℃发生Kumada重排反应,Si-Si键断裂并重排为Si-C-Si键,同时生成大量Si-H键;体系中Si-H键进一步与Al(AcAc)₃反应生成含有Si-O-Al结构的PACS先驱体。PACS先驱体的高温无机化转变过程主要分为三个阶段：(1)室温~300 ℃主要为吸附水和残留溶剂挥发;(2)300~700 ℃主要为侧链烷基裂解和主链断裂;(3)700~1000 ℃主要为残余氧和氢的脱除。1000 ℃高温裂解条件下,PACS-2先驱体陶瓷产率可达67.09%。同时,PACS-2先驱体展现出较好的熔融纺丝性能,可稳定制备连续初生纤维,纤维平均直径为(11.42±0.42) μm。经1800 ℃高温裂解后,PACS-2先驱体所得陶瓷产物以β-SiC为主晶相,含有少量α-SiC相、石墨相及非晶SiC_xO_y相,该温度下β-SiC晶粒尺寸为38.8 nm。PACS先驱体较高的陶瓷产率和良好的熔融纺丝性能,赋予其在制备连续SiC纤维领域较好的应用前景。本研究提出的“一步法”合成策略为设计与合成低成本SiC先驱体及其他陶瓷先驱体提供了新的技术思路。

关键词: 聚铝碳硅烷, 组成结构调控, 先驱体转化法, 碳化硅陶瓷, 碳化硅纤维

Abstract: Polyaluminocarbosilane (PACS) precursors are key raw materials for the preparation of heat-resistant silicon carbide (SiC) fibers. To overcome the technical limitations of the traditional “two-step” high-temperature pyrolysis route for PACS precursor synthesis, including complex processing and difficult regulation of composition and structure, a “one-step” atmospheric-pressure pyrolysis route was proposed in this study. Using polydimethylsilane (PDMS) and aluminum acetylacetonate (Al(AcAc)₃) as starting materials, the synthesis of the PACS precursor, the regulation of its composition and structure, the ceramization transformation process, as well as the composition and structure of the SiC ceramic products were systematically investigated. The results showed that by controlling the mass fraction of Al(AcAc)₃ in the feedstock (0-4%), the Al content and number-average molecular weight of the precursor could be effectively tailored within the ranges of 0.07%-0.47% and 1909-4302, respectively. When the Al(AcAc)₃ loading was 2%, the obtained PACS-2 precursor exhibited a softening point of 192.5 ℃ and a number-average molecular weight of 4302. The reaction mechanism of the “one-step” pyrolytic synthesis can be described as follows: at 450 ℃, PDMS undergoes the Kumada rearrangement, in which Si-Si bonds cleave and rearrange into Si-C-Si bonds with the concurrent generation of abundant Si-H bonds; these Si-H species further react with Al(AcAc)₃ to yield the PACS precursor containing Si-O-Al structures. The high-temperature inorganic transformation of the PACS precursor proceeds through three stages: (1) room temperature to 300 ℃, dominated by the volatilization of adsorbed water and residual solvent; (2) 300~700 ℃, dominated by the cleavage of side-chain alkyl groups and the scission of the main chain; (3) 700~1000 ℃, dominated by the elimination of residual oxygen and hydrogen. Pyrolyzed at 1000 ℃, the PACS-2 precursor afforded a ceramic yield of 67.09%. The PACS-2 precursor also exhibited good melt-spinning performance, from which continuous green fibers with an average diameter of (11.42±0.42) μm could be stably produced. After pyrolysis at 1800 ℃, the ceramic product derived from the PACS-2 precursor consisted mainly of the β-SiC crystalline phase, accompanied by minor amounts of α-SiC, graphite and an amorphous SiC_xO_y phase, with a β-SiC grain size of 38.8 nm at this temperature. The high ceramic yield and good melt-spinning performance of the PACS precursor endow it with promising application prospects in the field of continuous SiC fiber fabrication. Furthermore, the “one-step” synthesis strategy proposed in this study provides new technical insights for the design and synthesis of low-cost SiC precursors and other ceramic precursors.

Key words: polyaluminocarbosilane, composition and structure regulation, precursor conversion method, SiC ceramics, SiC fibers

中图分类号:

TQ343

邓渝, 张晓山, 张培垣, 王小宙. 聚铝碳硅烷先驱体的组成结构调控及转化碳化硅陶瓷研究[J]. 无机材料学报, DOI: 10.15541/jim20260301.

DENG Yu, ZHANG Xiaoshan, ZHANG Peiyuan, WANG Xiaozhou. Structural Control of Polyaluminocarbosilane Precursors and the Conversion to Silicon Carbide Ceramics[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20260301.

参考文献

[1] 罗瀚, 陈博文, 黄鹤飞, 等. 连续碳化硅纤维增强碳化硅陶瓷基复合材料在先进核能领域的发展研究. 中国工程科学, 2024, 26(3): 53.
[2] 黄靖翔, 黄浩, 周文龙, 等. 连续SiC纤维增强Ti60复合材料的热等静压致密化及热应力分布. 航空制造技术, 2025, 68(1): 101.
[3] 伍翠兰, 陈倩倩, 张勇, 等. 两种典型连续SiC纤维的精细微观结构及性能研究. 湖南大学学报: 自然科学版, 2019, 46(12): 71.
[4] GOU Y Z, KANG W F, ZHANG Q Y.Preparation of nearly stoichiometric SiC(Ti) fibers with highly crystalline microstructure from polytitanocarbosilane.Journal of Inorganic Materials, 2024, 39(12): 1377.
[5] BRAUN J, FELLAH C, LABRUGÈRE C,et al. Characterization of the Tyranno SA4 third generation SiC fiber surface and comparison with Tyranno SA3 and HNS fibers. International Journal of Applied Ceramic Technology, 2025, 22(3): e14988.
[6] MEI Y, ZHANG L, MO G M,et al. Improving SiC grain growth and reducing carbon content in pyrolyzed polycarbosilane using nanosized Si particles. Ceramics International, 2024, 50(13): 22771.
[7] 石南林. 高性能CVD法SiC纤维的研制. 材料导报, 2000, 14(7): 53.
[8] OKADA K, KATO H, NAKAJIMA K.Preparation of silicon carbide fiber from activated carbon fiber and gaseous silicon monoxide.Journal of the American Ceramic Society, 1994, 77(6): 1691.
[9] RYU Z, ZHENG J T, WANG M Z,et al. Preparation and characterization of silicon carbide fibers from activated carbon fibers. Carbon, 2002, 40(5): 715.
[10] DONG S M, CHOLLON G, LABRUGÈRE C,et al. Characterization of nearly stoichiometric SiC ceramic fibres. Journal of Materials Science, 2001, 36(10): 2371.
[11] DICARLO J A.Creep limitations of current polycrystalline ceramic fibers.Composites Science and Technology, 1994, 51(2): 213.
[12] 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.
[13] ISHIKAWA T, KOHTOKU Y, KUMAGAWA K,et al. High-strength alkali-resistant sintered SiC fibre stable to 2200 ℃. Nature, 1998, 391(6669): 773.
[14] SHIN D G, KONG E B, RIU D H,et al. Dense polycrystalline SiC fiber derived from aluminum-doped polycarbosilane by one-pot synthesis. Journal of the Korean Ceramic Society, 2007, 44(7): 393.
[15] WU S, GOU Y Z, WANG Y S,et al. Effect of heat treatment on composition, microstructure and mechanical property of domestic KD-SA SiC fibers. Journal of Inorganic Materials, 2023, 38(5): 569.
[16] GOU Y Z, KANG W F, WANG P R.Influence of sintering conditions on preparation of nearly stoichiometric SiC fibers with highly crystalline microstructure.Journal of Inorganic Materials, 2025, 40(4): 405.
[17] ZHOU X, LIU Z, REN Y,et al. Quantitative investigation of the creep resistance of different SiC fibers after annealing at high temperature. Journal of Inorganic Materials, 2026, 41(7): 1011.
[18] WANG P R, GOU Y Z, WANG H.Third generation SiC fibers for nuclear applications.Journal of Inorganic Materials, 2020, 35(5): 525.
[19] 李晓鸿, 张潇, 张梦娜, 等. 先驱体转化含铝碳化硅陶瓷纤维的制备研究进展. 硅酸盐学报, 2023, 51(6): 1595.
[20] XIE F C, DUAN Y P, MO G M,et al. Structural evolution of polyaluminocarbosilane during the polymer-ceramic conversion process. Materials, 2023, 16(11): 4172.
[21] CAO F, KIM D P, LI X D,et al. Synthesis of polyaluminocarbosilane and reaction mechanism study. Journal of Applied Polymer Science, 2002, 85(13): 2787.
[22] 袁钦. 第三代连续SiC纤维制备过程基础研究. 长沙: 国防科学技术大学博士学位论文, 2016.
[23] YU Y X, LI X D, CAO F.Synthesis and characterization of polyaluminocarbosilane.Journal of Materials Science, 2005, 40(8): 2093.
[24] 甄霞丽, 裴学良, 钟希强, 等. 基于聚硅碳硅烷与仲丁醇铝制备含铝碳化硅纤维. 合成纤维, 2018, 47(9): 25.
[25] 郑春满, 李效东, 余煜玺, 等. 耐超高温SiC(Al)纤维先驱体——聚铝碳硅烷纤维的研究. 高分子学报, 2006, 37(6): 768.
[26] GOU Y Z, WANG H, JIAN K,et al. Facile synthesis of melt-spinnable polyaluminocarbosilane using low-softening-point polycarbosilane for Si-C-Al-O fibers. Journal of Materials Science, 2016, 51(17): 8240.
[27] DUAN Y P, MO G M, CHEN H J,et al. Synthesis of polyaluminocarbosilane with low branched molecular structure using liquid polysilacarbosilane and aluminum acetylacetonate by high-pressure method. Applied Organometallic Chemistry, 2019, 33(2): e4720.
[28] LI X D, EDIRISINGHE M J.Structural investigation of Si-Al-C-O precursors and their pyrolysis products in nitrogen.Proceedings of the Royal Society of London Series A: Mathematical, Physical and Engineering Sciences, 2003, 459(2039): 2731.
[29] 王堋人. SA型SiC纤维烧结致密化机理及高温性能研究. 长沙: 国防科技大学博士学位论文, 2020.
[30] VAN DIJEN F K, METSELAAR R. The chemistry of the carbothermal synthesis ofβ-SiC: reaction mechanism, reaction rate and grain growth. Journal of the European Ceramic Society, 1991, 7(3): 177.
[31] JIANG L, CONG Y, DU X L,et al. Preparation and characterization of silicon carbide-derived carbon/mesophase pitch carbon composites. Journal of Functional Materials, 2015, 46(24): 24127.
[32] HE Y, MO G M, LI P,et al. Initiating the crystallization of SiC at as low as 800 ℃ in polycarbosilane using Al-Si alloy powders. Ceramics International, 2025, 51(20): 31848.
[33] WANG K W, MA B S, LI X Q,et al. Structural evolutions in polymer-derived carbon-rich amorphous silicon carbide. The Journal of Physical Chemistry A, 2015, 119(4): 552.
[34] CHEN Y H, YANG X P, CAO Y J,et al. Quantitative study on structural evolutions and associated energetics in polysilazane-derived amorphous silicon carbonitride ceramics. Acta Materialia, 2014, 72(1): 22.