SiC纤维及其增强SiCf/SiC复合材料的研究进展

SiC_f/SiC复合材料的低密度、耐高温、抗环境腐蚀及抗氧化等突出性能,使其在航天及空天飞行器的热端部件、热防护结构、发动机热端部件及核工业等领域取得了重大应用,是新一代最佳的高温结构材料。SiC纤维作为增强相,自身抗拉强度高、抗蠕变性能好、兼具耐高温、抗氧化等优点,且与陶瓷基体有着优异的相容性,可使陶瓷复合材料克服脆性,具有韧性,极大地推动了陶瓷复合材料的应用。文章以碳化硅纤维研发技术的三个重要发展阶段为例,详细阐述了碳化硅纤维的制备方法及性能特点,同时对碳化硅纤维增强陶瓷基复合材料的不同制备工艺进行了介绍,并分析了该复合材料当前国内外的应用现状,文章简述了SiC_f/SiC复合材料的发展及推广前景。     

碳化硅陶瓷基复合材料基体和涂层改性研究进展

随着航空航天器性能的提高,其热端部件如航空发动机、高超音速飞行器的头锥及翼前缘等服役环境愈加苛刻。为了满足更苛刻的服役环境,需要对碳化硅陶瓷基复合材料(SiC matrix ceramic composites,CMC–Si C)进行基体或涂层改性以发展更长寿命、更耐高温和结构功能一体化的陶瓷基复合材料。介绍了航空航天器热端部件用CMC–SiC复合材料基体和涂层改性的研究进展、成果、现状及存在的问题,指出了今后需要着重解决改性CMC–SiC复合材料的工程化应用问题、发展具有更高使用温度的改性材料体系以及发展在发动机环境中应用的环境屏障涂层体系。     

碳化硅陶瓷基复合材料基体和涂层改性研究进展EI北大核心CSCD

随着航空航天器性能的提高,其热端部件如航空发动机、高超音速飞行器的头锥及翼前缘等服役环境愈加苛刻。为了满足更苛刻的服役环境,需要对碳化硅陶瓷基复合材料(SiC matrix ceramic composites,CMC-Si C)进行基体或涂层改性以发展更长寿命、更耐高温和结构功能一体化的陶瓷基复合材料。介绍了航空航天器热端部件用CMC-SiC复合材料基体和涂层改性的研究进展、成果、现状及存在的问题,指出了今后需要着重解决改性CMC-SiC复合材料的工程化应用问题、发展具有更高使用温度的改性材料体系以及发展在发动机环境中应用的环境屏障涂层体系。     

碳纤维增强碳化硅基复合材料的研究

碳纤维增强碳化硅基复合材料(Cf/SiC)具有良好的力学性能,作为特殊结构的功能材料,是航空航天领域和新能源领域的研究热点之一。本文主要阐述了增强相碳纤维的发展,复合材料的基体复合技术,以及复合材料界面相的研究,并展望了碳纤维复合材料在高新技术领域中的应用与发展前景。     

SiC/SiC复合材料及其应用

日本开发的Nicalon和Tyranno两种品牌的SiC纤维占有世界上绝对性的市场份额。SiC/SiC复合材料典型的界面层是500 nm厚的单层热解碳(PyC)涂层或多层(PyC-SiC)n涂层,在湿度燃烧环境及中高温条件下界面层的稳定性是应用研究的重点。SiC/SiC复合材料,包括CVI-SiC基体和日本开发的Tyranno hex和NITE-SiC基体等,具有耐高温、耐氧化性和耐辐射性的特点,在航空涡轮发动机部件、航天热结构部件及核聚变反应堆炉第一壁材料等方面正开展工程研制应用。     

碳化硅CVI工艺沉积动力学模拟研究

化学气相渗透(CVI)工艺被广泛应用于制备碳基及碳化硅(SiC)基复合材料，CVI工艺是实现制备高纯度和高晶粒度SiC基体的SiC_f/SiC复合材料最佳方案。为了优化CVI制备SiC基体的工艺参数，本文主要研究了CVI工艺沉积SiC的动力学机理及数值模拟。对于CVI工艺SiC沉积的动力学，本文提出了SiC沉积过程的反应动力学机理模型，并通过耦合反应器内的流场和浓度场，模拟了甲基三氯硅烷(MTS)在CVI过程中的SiC沉积实验。通过对样品在CVI致密化过程中孔隙率的实验结果与模拟结果比较，表明该SiC沉积动力学模型的合理性。通过模拟获得了在反应器内的速度场和各组分(MTS, CH₃,SiCl₃)的浓度场分布情况，以及预制体致密化过程的密度分布情况。以上SiC的CVI工艺动力学模拟，对未来优化SiC_f/SiC复合材料CVI工艺具有重要的指导意义。     

SiCf/SiC复合材料高温抗氧化研究进展

连续SiC纤维增韧SiC陶瓷基复合材料(SiCf/SiC CMCs)具有低密度、优异的高温力学性能和抗氧化性能,在航空发动机热端部件上具有广阔的应用前景,具备提高发动机推重比和使用温度、减轻无效重量、简化系统结构等显著优势.延长SiCf/SiC复合材料在航空发动机高温氧化环境下的服役寿命是当前需要解决的难题.本文从纤维、界面相、基体、表面涂层四个方面综述了SiCf/SiC复合材料高温抗氧化研究进展.采用多元多层自愈合界面相、对基体进行改性以及采用表面自愈合整体涂层都可以有效提高SiCf/SiC复合材料在高温氧化环境中的使用稳定性和寿命.     

碳/碳化硅摩阻复合材料的研究进展

碳/碳化硅是近年来发展起来的一种新型高性能陶瓷基摩阻材料,具有密度低,抗氧化性好,摩擦性能高且性能稳定等一系列优点,在高速列车、飞机和重型汽车等高能载制动领域具有广泛的应用前景.反应性熔体浸渗法是制备碳/碳化硅摩阻复合材料的有效途径.从碳/碳化硅摩阻复合材料的设计出发,深入分析了反应性熔体渗透过程的热力学条件,Si-C反应体系的基本特征以及动力学规律.针对短纤维模压和三维针刺等两种典型C/SiC复合材料的制备过程,对材料的微结构特征和摩擦磨损性能进行了系统论述.同时,对红外热成像、X射线透射和工业CT等先进工程检测方法在碳/碳化硅摩阻复合材料构件上的应用进行了分析.     

碳纤维增强碳化硅陶瓷基复合材料的研究进展及应用

碳纤维增强碳化硅陶瓷基复合材料具有密度低、高强度、高韧性和耐高温等综合性能,已得到世界各国高度重视.本文综述了碳纤维的研究进展,C_f/SiC复合材料的制备方法,并分析了各种制备方法的优缺点.概述了C_f/SiC复合材料作为高温热结构材料和制动材料的应用状况.最后,指出了有待解决的问题和今后的主要研究方向.     

连续碳纤维增韧碳化硅基复合材料数据库

连续碳纤维增韧碳化硅基复合材料(C/SiC)数据库为C/SiC复合材料的研究和应用提供了一个高效的数据存储、管理和访问的平台,实现了从材料制备、试样加工到性能试验的全过程的信息管理,包含了物理性能、力学性能、热物理化学性能等多种类型的数据,并提供了数据管理功能和一些应用工具.系统采用了最先进的软硬件平台以延长系统的生命周期,应用了一些新的数据库技术,如对像数据类型、统一建模语言(UML)等,简化了数据库的逻辑结构.制定了数据规范、约束、触发器等保证数据的完整性和一致性,并建立了严格的安全机制.     

Removal mechanism of SiC/SiC composites by underwater femtosecond laser ablation

Silicon carbide Ceramic matrix composites (SiC matrix with SiC fibers, abbreviated as SiC/SiC composites) are widely used in aerospace and energy applications due to their excellent resistance to high temperatures, corrosion, wear, and low density. However, the difficult machinability and surface oxidation of SiC/SiC composites are the main factors restricting their further application. To address these issues, this paper explores a novel method for underwater femtosecond laser ablation of SiC/SiC composites to obtain high cleanliness, low-oxidation microporous surfaces. This paper systematically analyses the changes in hole depth, material removal rate (MRR), surface morphology, and material components during underwater femtosecond laser ablation of SiC/SiC composites, and explains the formation of typical features such as induced cones, small banded pits, fiber debonding and shedding. Our work provides new research ideas for understanding the removal mechanism and surface oxidation resistance of SiC/SiC composites.     

裂解碳包覆对SiC纳米纤维增强SiC陶瓷基复合材料性能的影响

以SiC纳米纤维(SiC_nf)为增强体,通过化学气相沉积在SiC纳米纤维表面沉积裂解碳(PyC)包覆层,并与SiC粉体、Al₂O₃-Y₂O₃烧结助剂共混制备陶瓷素坯,采用热压烧结工艺制备质量分数为10%的SiC纳米纤维增强SiC陶瓷基(SiC_nf/SiC)复合材料。研究了PyC包覆层沉积时间对SiC_nf/SiC陶瓷基复合材料的致密度、断裂面微观形貌和力学性能的影响。结果表明:在1 100 ℃下沉积60 min制备的PyC包覆层厚度为10 nm,且为结晶度较好的层状石墨结构;相比于纤维表面无包覆层的复合材料,复合材料的断裂韧性提高了35%,达到最大值(19.35±1.17) MPa·m^1/2,抗弯强度为(375.5±8.5) MPa,致密度为96.68%。复合材料的断裂截面可见部分纳米纤维拔出现象,但SiC_nf/SiC陶瓷基复合材料界面结合仍较强,纳米纤维拔出短,表现为脆性断裂。     

Fabrication and performance of mini SiC/SiC composites with an electrophoresis-deposited BN fiber/matrix interphase

The feasibility of fabricating a BN matrix/fiber interphase of SiC/SiC composites via electrophoresis deposition (EPD) was investigated based on the simplicity and non-destructiveness of the process and the excellent interfacial modification effects of BN. The BN suspension and SiC fiber surface properties were both adjusted to generate suitable conditions for the EPD process of the BN interphase. Next, the deposition dynamics and mechanism were studied under different deposition voltages and time, and the relationship between the deposition morphology of the BN interphase and mechanical properties of the fabricated mini SiC/SiC composites were also discussed. After oxidation at high temperature (600–1000 ℃), the mechanical properties of the mini SiC/SiC composites were studied to verify the oxidation resistance effect of the EPD-deposited BN interphase, whose oxidation resistance mechanism was briefly analyzed as well.     

A focused review on the tribological behavior of C/SiC composites: Present status and future prospects

Silicon carbide-based ceramic matrix composites have received extensive attention in recent years. Many excellent reviews have reported on the tribological behavior of carbon fiber-reinforced carbon and silicon carbide dual matrix (C/C-SiC) composites. However, a systematic overview of the tribological properties of carbon fiber-reinforced silicon carbide (C/SiC) composites does not exist. This review focuses on C/SiC composites and summarizes the key factors, including internal factors (constituent content, graphitization process, material structure and fiber direction), and various test conditions (pressure and speed, dry and wet, temperature, and counterparts) that affect their tribological behavior. Their wear mechanisms under different conditions are elaborated. Finally, some potential future development directions for improving the performance of C/SiC composites are proposed to provide high-quality ceramic matrix composites for engineering applications. These directions include structural modification, matrix modification, coating technology, laser surface texturing, and material genome method.     

Strengthening/toughening of 2D C/SiC composites by coating

SiC and SiC_w/SiC coatings were prepared on two-dimensional carbon fiber reinforced silicon carbide ceramic matrix composites (2D C/SiC), and strengthening/toughening of the composite by the coatings was investigated. After coating, the density of the C/SiC composites was increased effectively and the mechanical properties were improved significantly. Compared with SiC coating, SiC_w/SiC coating showed the more significant effect on strength/toughness of the composites. Coatings had two effects: surface strengthening and matrix strengthening. The latter was the dominant effect. The surface strengthening can increase the crack initiation stress, while the matrix strengthening can enhance the crack propagation resistance. The former effect increased the strength and the latter effect increased the toughness.     

Effect of the fabrication process on the microstructural evolution of carbon fibers and flexural property on C/SiC composites by the NITE method

Nano-infiltration and transient eutectic phase (NITE) SiC matrix composites are designed for application in aerospace propulsion systems, particularly in fasteners and thrusters. A variety of carbon fibers with different properties have been selected as reinforcements for SiC matrix composites. Carbon fibers are known to be stable at high temperatures; however, the effects of high applied pressure at high temperatures on the fiber microstructure evolution and mechanical properties are not well-known. As a scoping study for fabricating NITE C/SiC composites, the behaviors of various carbon fibers in SiC composites. Pitch-based fibers, namely, GRANOX XN-05 and YS-90A, and a polyacrylonitrile-based fiber, namely, TORAYCA T-300B, were selected for matrix reinforcement. The 3-point bending test results indicated pseudo-ductile behaviors in the cases of YS-90A and T-300B fiber reinforcements. Fracture resistance evaluation based on the single-notch bending test indicated that the YS-90A fiber reinforced composite afforded the highest fracture resistance among the three C/SiC composites. The microstructure evolution on YS-90A and T-300B fibers was limited to near the fiber surface. Therefore, YS-90A and T-300B carbon fibers are potential candidates for reinforcement in NITE C/SiC composites.     

Oxidation and thermal shock resistant properties of Al-modified environmental barrier coating on SiCf/SiC composites

SiC_f/SiC ceramic matrix composites (CMCs) are being widely used in the hot-sections of gas-turbines, especially for aerospace applications. These CMCs are subjected to surface recession if exposed to heat-corrosion. In this research, an alternative environmental barrier coating (EBC) is introduced to protect the SiC_f/SiC CMC from high temperature degradation that is, Al film was deposited on the surface of SiC_f/SiC CMC followed by heat-treatment in a vacuum. After that, a dense Al₂O₃ overlay was in-situ synthesized on the surface of CMC, and in this process the microstructure evolution of SiC_f/SiC CMC was analyzed. The oxidation and thermal shock resistance were characterized, showing that the Al-modified SiC_f/SiC CMC has a better oxidation resistance, because the dense Al₂O₃ overlay can hinder oxygen diffusion from environment. What is more, the water-quenching testes show that the Al-modified SiC_f/SiC CMC has a good spallation resistance.     

Interaction of fiber matrix bonding in SiC/SiC ceramic matrix composites

Non-oxide ceramic matrix composites (CMC) based on SiC fibers with SiC matrix were fabricated by polymer infiltration and pyrolysis (PIP) and characterized regarding their microstructural features and their mechanical properties. The fiber preform was made using winding technology. During the winding process, the SiC fiber roving was impregnated by a slurry containing SiC powder and sintering additives (Y₂O_3, Al₂O₃ and SiO₂). This already helped to achieve a partial matrix formation during the preform fabrication. In this way, the number of PIP cycles to achieve composites with less than 10% open porosity could be reduced significantly. Additionally, damage-tolerant properties of the composites were obtained by an optimal design of the matrix properties although only uncoated fibers were used. Finally, composites with a strength level of about 500 MPa and a damage-tolerant fracture behavior with about 0.4% strain to failure were obtained.     

核用SiCf/SiC复合材料研究进展

核用SiC_f/SiC复合材料是国际上材料研究的一个热点,本文简要介绍了SiC_f/SiC复合材料的制备工艺,重点综述了SiC_f/SiC复合材料的抗辐照性能和耐腐蚀性能等方面的研究成果,详细介绍了SiC_f/SiC复合材料燃料包壳管的研究进展,并对核用SiC_f/SiC复合材料研究中需要关注的重点问题提出了几点思考。     

Novel Cr2AlC MAX-phase/SiC fiber composites: Synthesis,processing and tribological response

A new class of ceramic matrix composites based on Cr₂AlC MAX-phase containing 5 and 10 wt.% of SiC fibers was developed in this investigation. The Cr₂AlC/SiC composites were performed through two consecutives steps: i) synthesis of the pure Cr₂AlC phase from its elemental constituents by reactive method under argon atmosphere at 1400 °C and particle size refinement, and ii) processing of Cr₂AlC powder and SiC fibers followed by densification using the field assisted sintering technology/spark plasma sintering. Cr₂AlC/SiC composites presented high density (98.6%) with an excellent dispersion of the fibers within the matrix and a strong matrix/fiber interfase. Tribological behavior of the developed composites was studied under dry conditions to reveal the role played by the SiC fibers. Incorporation of the SiC fibers within the Cr₂AlC matrix reduced the friction coefficient up to 20% for low testing loads, while the wear resistance increased up to 70–80% independently of the applied load.