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Silicon carbide fiber-reinforced silicon carbide matrix composites (SiC/SiC CMCs) are promising candidates for hot gas components in jet engines. Three common manufacturing routes are chemical vapor infiltration, reactive melt infiltration (RMI) and polymer infiltration and pyrolysis (PIP). A combination of the processes seems attractive: the remai...
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... to three PIP cycles before the final LSI step were sufficient; with more infiltrations the matrix was already too dense for melt infiltration. By using only two PIP cycles the overall processing time could be reduced by 55 % compared to stand-alone PIP process (Table 4). As weak interphase and to protect the fibers from the aggressive silicon melt, a CVD fiber coating system is required. ...Context 2
... to three PIP cycles before the final LSI step were sufficient; with more infiltrations the matrix was already too dense for melt infiltration. By using only two PIP cycles the overall processing time could be reduced by 55% compared to stand-alone PIP process (Table 4). As weak interphase and to protect the fibers from the aggressive silicon melt, a CVD fiber coating system is required. ...Citations
... Additionally, shrinkage cracks and structural collapse from the pyrolysis of phenolic resin further contributed to the formation of closed pores. Conversely, the carbon matrix within the SiC fiber bundles remained largely intact, featuring a relatively thicker carbon layer, which could hinder subsequent molten silicon infiltration [31]. Figure 2b,e depict that the the interstitial spaces between the fiber bundles of PS preform are filled with a significant amount of SiC powder, effectively reducing porosity. ...
This study investigated the influence of preformed composition and pore size on the microstructure and properties of SiCf/SiC composites fabricated via reactive melt infiltration (RMI). The process began with the impregnation of SiC fiber cloth with phenolic resin, followed by lamination and pyrolysis. Subsequent steps included further impregnations with phenolic resin, SiC slurry, and carbon black slurry, each followed by additional pyrolysis. This process resulted in three types of preforms, designated as PP, PS, and PC. These preforms exhibited a multimodal distribution of pore size, with peak pore diameters around 5 μm for PP, ranging from 200 nm to 4 μm for PS, and approximately 150 nm for PC. The preforms were then subjected to molten silicon infiltration at 1600 °C under vacuum for 1 h to create SiCf/SiC composites. The PP preform contained only pyrolytic carbon, leading to a composite with high closed porosity and unreacted carbon, resulting in poor mechanical properties. The PS preform, which was impregnated with SiC particles, displayed an optimized pore size distribution but retained significant amounts of residual silicon and carbon in the final composite. In contrast, the PC preform featured both an ideal pore size distribution and an adequate amount of carbon, achieving high density and low porosity with reduced residual phases in the final composite. This optimization led to a flexural strength of 152.4 ± 15.4 MPa, an elastic modulus of about 181.1 ± 0.1 GPa, and a thermal conductivity of 27.7 W/mK in the SiCf/SiC composites product. These findings underscore the importance of preform optimization in enhancing the performance of SiCf/SiC composites, potentially paving the way for more reliable nuclear fuel cladding solutions.
... In practical production, CMCs are not always obtained through one of those methods. In some works, combining those four methods is also adopted to increase the density, shorten production periods, and reduce costs [368][369][370][371]. ...
Carbide ceramic fibers are of significant importance for application in the high-tech areas of advanced aircraft engines, aerospace vehicles, and the nuclear industry due to their excellent properties, such as high tensile strength and elastic modulus, excellent high-temperature resistance, and oxidation resistance. This paper reviews the preparation and application of different carbide ceramic fibers, including SiC fibers and transition metal carbide (e.g., ZrC, HfC, and TaC) ceramic fibers. The preparation methods of carbide ceramic fibers are discussed in terms of different fiber diameters, represented by SiC fibers with variable weaving properties and functions due to their differences in diameter. Subsequently, the application of carbide ceramic fibers as high-temperature-resistant structural materials, catalyst carriers, sensors, and supercapacitors are summarized, and strategies for the future development of carbide ceramic fibers are proposed. This review aims to help researchers enhance their understanding of the preparation and utilization of carbide ceramic micro/nanofibers, advancing the development of high-performance carbide ceramic fibers.
... There are three established production processes to integrate CF into a SiC: chemical vapor infiltration (CVI), precursor infiltration and pyrolysis (PIP), which is also called liquid polymer infiltration (LPI), and liquid silicon infiltration (LSI), which is used for the production of automotive brake discs [16]. The CVI and PIP/LPI-processes are mainly used for the production of continuously reinforced parts, whereas the LSI process is also used for processing short fiber reinforced parts [17][18][19]. The LSI process has three main steps: (1) shaping of the CF reinforced plastic (CFRP) part, where multiple processes like pressing, RTM, or filament winding can be used; (2) pyrolysis to C/C to detach all noncarbons and form a crack network; and (3) liquid silicon infiltration into the cracks to form C/C-SiC. Typical matrix materials have a rather high char yield and are dimensionally stable during pyrolysis [20,21]. ...
The inductive heating of a CMC susceptor for industrial applications can generate very high process temperatures. Thus, the behavior of a silicon carbide-based matrix with carbon-fiber-reinforced carbon (C/C-SiC) as a susceptor is investigated. Specifically, the influence of fiber length and the distribution of carbon fibers in the composite were investigated to find out the best parameters for the most efficient heating. For a multi-factorial set of requirements with a combination of filling levels and fiber lengths, a theoretical correlation of the material structure can be used as part of a digital model. Multi-physical simulation was performed to study the behavior of an alternating magnetic field generated by an inducing coil. The simulation results were verified by practical tests. It is shown that the inductive heating of a C/C-SiC susceptor can reach very high temperatures in a particularly fast and efficient way without oxidizing if it is ensured that a silicon carbide-based matrix completely encloses the fibers.
... As a new generation of thermal structural materials, SiC CMC have excellent properties such as low density, high temperature resistance, corrosion resistance and high strength [1,2]. Due to the reinforcement and toughening of fibers, the stability and reliability of SiC CMC in extreme environments have been significantly improved, which shows great application capability in aerospace, transportation, light construction and other fields [3][4][5]. The device applications based on fiber reinforced SiC CMC are gradually increasing, which poses higher requirements and challenges for its processing due to high hardness and anisotropy. ...
... Previous studies have shown that melt infiltration (MI) followed by hot pressing decreases the thermal stability of the matrix due to the presence of residual silicon or sintering additives. In the case of chemical vapor infiltration (CVI), uniform and effective infiltration of the matrix by a gas phase route enables excellent properties and near net-shaped CMC production at relatively low temperatures [4,14], but long processing times and high costs have suppressed the wide use of CVI [10,15]. ...
... One of the disadvantages of the PIP process is the decrease in densification efficiency with the increasing the number of infiltration/pyrolysis steps. As close porosity increases, the infiltration of the liquid precursor into the specimen is suppressed [15]. However, the densification efficiency did not decrease for up to four PIP cycles for the PRC, as shown in Figure 1a, indicating that the formation of closed pores did not occur at the surface of the specimens for up to four PIP cycles. ...
... The second method is to fabricate protective coatings on the PyC layer, such as PyC/SiC or PyC/BN/SiC [14,15]. Sing et al. applied single-layer pyrocarbon (PyC) coatings and multilayer PyC/SiC interfaces to the carbon fibers in C f /SiC CMCs when the matrix was processed by the I-CVI method. ...
The thermomechanical properties of carbon fiber reinforced silicon carbide ceramic matrix composites (Cf/SiC CMCs) were studied up to 2000 °C using high-temperature in situ flexural testing in argon. The CMC specimens were fabricated using an ultrahigh concentration (66 vol%) aqueous slurry containing nano-sized silicon carbide powder. The SiC powder compacts were obtained by drying the slurry and were densified using the precursor impregnation and pyrolysis (PIP) method with field assisted sintering technology/spark plasma sintering (FAST/SPS). The high relative density of the SiC green body (77.6%) enabled densification within 2.5 days using four PIP cycles. In contrast, conventional PIP processes take over 7 days. The in situ flexural strength of the Cf/SiC CMC was 434 MPa at 1750 °C, which was 84% higher than the room temperature value. The value further increased to 542 MPa at 2000 °C. Possible mechanisms to explain the excellent strength of the CMC at elevated temperatures are discussed.
... These environments demand superior material properties (e.g. carbon fiber reinforced silicon carbide (C/C-SiC) for rocket nozzles, silicon carbide fiber reinforced silicon carbide (SiC/SiC) turbine shrouds for jet engines) [5][6][7]. The group of radomes is one such component category where CMCs are a favorable material due to its excellent performance. ...
... These environments demand superior material properties (e.g. carbon fiber reinforced silicon carbide (C/C-SiC) for rocket nozzles, silicon carbide fiber reinforced silicon carbide (SiC/SiC) turbine shrouds for jet engines) [5][6][7]. The group of radomes is one such component category where CMCs are a favorable material due to its excellent performance. ...
... Silicon carbide is an important non-oxide ceramic which has diverse industrial applications due to its outstanding properties, such as very high hardness and strength, chemical, and thermal stability, high melting point, oxidation resistance, high erosion resistance, excellent thermal shock resistance. The material may be produced by pyrolysis from preceramic polymer, for example, polycarbosilane [21,22]. The material based on polycarbosilane ceramic matrix can stabilize cobalt ferrite nanoparticles [23]. ...
Composite materials comprised of a ceramic matrix with metal-containing nanoparticles were prepared by sintering iron (II) oxalate and polycarbosilane. The chemical composition of the material can be controlled by a sintering process. Sintering in inert atmosphere leads to reduction of the sample and metal iron formation (a-Fe, carbide). Formation of iron oxides requires calcination procedure in series (argon and air) for removing by products. The air-sintering materials consist mainly of oxide phases, but also contain metal iron. The prepared samples were characterized by the: SEM, TEM, XRD and EMR techniques and the Mössbauer spectroscopy. It was shown unique behavior that iron containing particles after calcination in air decreased from 5-30 nm to 2–5 nm due to interaction with matrix under air atmosphere.
... SiC f /Mo 3 Si 2 C showed a 78% increase in the creep resistance over that of SiC f /Mo 2 AlSi 3 . In another study, Süß et al. [27] combined the LSI and PIP processes for matrix densification. After 1-5 cycles of the PIP process, SiC f /SiC was manufactured by pyrolysis at 1450 • C and an LSI process at 1400 • C. ...
In order to improve the degree of matrix densification of SiCf/SiC composites based on liquid silicon infiltration (LSI) process, the microstructure and mechanical properties of composites according to various pyrolysis temperatures and melt infiltration temperatures were investigated.
Comparing the microstructures of SiCf/C carbon preform by a one-step pyrolysis process at 600 °C and two-step pyrolysis process at 600 and 1600 °C, the width of the crack and microcrack formation between the fibers and matrix in the fiber bundle increased during the two-step pyrolysis process. For each pyrolysis process, the density, porosity, and flexural strength of the SiCf/SiC composites manufactured by the LSI process at 1450–1550 °C were measured to evaluate the degree of matrix densification and mechanical properties. As a result, the SiCf/SiC composite that was fabricated by the two-step pyrolysis process and LSI process showed an 18% increase in density, 16%p decrease in porosity, and 150% increase in flexural strength on average compared to the composite fabricated by the one-step pyrolysis process.
In addition, among the SiCf/SiC specimens fabricated by the LSI process after the same two-step pyrolysis process, the specimen that underwent the LSI process at 1500 °C showed 30% higher flexural strength on average than those at 1450 or 1550 °C. Furthermore, under the same pyrolysis temperature, the mechanical strength of SiCf/SiC specimens in which the LSI process was performed at 1500 °C was higher than that of the 1550 °C although both porosity and density were almost similar. This is because the mechanical properties of the Tyranno-S grade SiC fibers degraded rapidly with increasing LSI process temperature.
... Silicon carbide is an important non-oxide ceramic which has diverse industrial applications due to its outstanding properties, such as very high hardness and strength, chemical, and thermal stability, high melting point, oxidation resistance, high erosion resistance, excellent thermal shock resistance. The material may be produced by pyrolysis from preceramic polymer, for example, polycarbosilane [21,22]. The material based on polycarbosilane ceramic matrix can stabilize cobalt ferrite nanoparticles [23]. ...
