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Properties of silicon carbide fibers obtained by silicification of carbon fabric with SiO vapours
Abstract
The method of siliconizing carbon fabric with SiO vapours yields a textile SiC material that preserves the structure and integrity of the fibers of the original fabric, as well as the average diameter of the monofilament. According to X-ray phase analysis, it was found that SiC fibres obtained by siliconizing silicon fabric with SiO vapor consist of a mixture of two modifications of 3C–SiC and 6H–SiC. According to infrared absorption, the oxygen content in the composition of silicon carbide fibers does not exceed 2.1 wt%. The mechanical properties of the obtained fibers were investigations: the mechanical tensile strength of silicon carbide fibers is σp = 1350 ± 120 MPa, the nanoscale hardness is 10 ± 0.5 GPa, and the elastic modulus is 100 ± 10 GPa.
... Materials based on silicon carbide (SiC) are wellknown for their use as high-temperature structural and refractory materials [1][2][3][4][5]. The combination of high corrosion resistance, mechanical strength, thermal conductivity, and consequently, resistance to thermal shock is particularly relevant for metallurgical applications. ...
... The normal density was calculated using the formula: (2) normal density = m W m C i 100 (1) Where: m w -weight of suspended water, g m c -weight of suspended cement, g ...
In order to reduce the water demand of silicon carbide vibratory casting masses with high-alumina cement additives, the impact of various deflocculant of different natures to silicon carbide vibratory casting masses was investigated. The deflocculants used included polycarboxylate ether-based, sodium polyacrylate, high-molecular-weight poly-N-vinylpyrrolidone, and sodium salts of polymethylene-β-naphthalenesulfoxylic acid. Multifractional compositions of silicon carbide (2-3 mm, 1-2 mm, 0,5-1 mm, 0,2-0,5 mm, 0,063-0,12 mm fractions) with high-alumina cement and silicon additives, as well as with deflocculants, were studied. The firing of the materials was conducted in an oxygen atmosphere at temperatures between 1000 and 1400˚С. The adverse effect was demonstrated for deflocculant based on sodium polyacrylate and high-molecular-weight poly-N-vinylpyrrolidone, as the usage of these additives increases the water demand of the mix. A smaller amount of water used for the mass production allows the processing of more dense materials with reduced open and closed porosity. Using deflocculants, the moisture content of the material is reduced to 6.5%.
... In 1994, Okada et al. [199,200] employed the reaction between activated carbon fiber (ACF) and silicon monoxide (SiO) at high temperature and low pressure to obtain SiC fibers, then densified the fibers by heat treatment. Since then, many researchers have conducted related studies inspired by Okada's work [201][202][203][204][205][206][207][208][209][210]. For example, Ryu et al. [201] prepared SiC fibers by a vapor-solid (V-S) reaction between PAN-basedactivated carbon fibers (PAN-ACF) and SiO gas. ...
... The SiO gas was produced from a mixture of silicon (Si) and silicon dioxide (SiO2) at temperature ranging from 1200 °C to 1300 °C in inert atmosphere. In recent years, Istomina et al. [202] explored selecting the SiO gas source and designed the reactor for preparing SiC fibers using PAN-based carbon fibers. The obtained fibers' tensile strength and elastic modulus were about 1.3 ...
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.
... The silicon carbide (SiC) ceramic is a perspective material for many branches of manufacture because of its unique complex of physical-chemical properties, such as mechanical engineering, aviation, defense equipment, cutting tools, etc. [1][2][3][4][5][6][7][8]. ...
... The SiC SHS ceramic density is higher than that of SiC SHS ceramic (Table 1). This is because the SHS silicon carbide powder particles, due to the spherical shape of the particles and the size of 100-400 nm, are compacted better [1] than the SiC SG powder of the fragmented form of particles with a size of 1 µm. In addition, the presence of elongated silicon nitride grains in SiC SHS powder contributes to the creation of a reinforced structure since elongated grains are also observed after sintering (Fig. 5a, b). Figure 6 shows 3D models of grooves formed on ceramic samples from Saint Gobain and SHS silicon carbide powder after wear testing, respectively Fig. 6a and 6b. ...
The hot press method obtained the SiC composite from different morphology and partial size powder. The starting SiC powder was: 1) fragmentation particle shape industrial charge of silicon carbide obtained by the Acheson method with sintering additive (9 wt.% Y 2 O 3 − Al 2 O 3 ) by Saint Gobain, 2) spherical particles SiC obtained by SHS in a laboratory. Bending strength, critical stress intensity factor, density, the friction coefficient of samples of the obtained ceramics were determined. It has been established that the properties of ceramics obtained from SHS silicon carbide powder (spherical particles with sizes of 100–400 nm), due to better compaction, were at least 10% higher than samples from Saint Gobain powder: bending strength 400 ± 22 MPa, density 3.23 ± 0.01 g/cm ³ , critical stress intensity factor К 1С = 4.8 ± 0.3 MPa∙m 1/2 , friction coefficient 0.1126 ± 0.0031.
... The silicon carbide (SiC) ceramic is a perspective material for many branches of manufacture because of its unique complex of physical-chemical properties, such as mechanical engineering, aviation, defense equipment, cutting tools, etc. [1][2][3][4][5][6][7][8]. ...
The hot press method was used to obtain the SiC composite from different morphology and partial size powder. The starting SiC powder was: 1) fragmentation particle shape industrial charge of silicon carbide obtained by the Acheson method with sintering additive (9 wt.% Y2O3 − Al2O3) by Saint Gobain, 2) spherical particles SiC obtained by SHS in a laboratory. Bending strength, critical stress intensity factor, density, and the friction coefficient of samples of the obtained ceramics were determined. It has been established that the properties of ceramics obtained from SHS silicon carbide powder (spherical particles with sizes of 100–400 nm), due to better compaction, were at least 10% higher than samples from Saint Gobain powder: bending strength (400 ± 22 MPa), density (3.23 ± 0.01 g/cm³), critical stress intensity factor (К1С = 4.8 ± 0.3 MPa∙m1/2), friction coefficient (0.1126 ± 0.0031).
... The process involves siliconised silicon fabric with silicon monoxide vapour at 1400 °C with a pressure of 0.09 Pa to produce a combination of cubic (3C-SiC) and hexagonal SiC (6H-SiC). SiC fibres have a high mechanical tensile strength of 1470 MPa, a nanoscale hardness of 10 GPa, and an elastic modulus of 110 GPa [37]. ...
Over the past several decades, industrialised and developing nations have attempted to enhance sustainability. Demands for energy and the acceleration in environmental deterioration are the two primary obstacles to progress. The daily generation of municipal solid waste has been a significant factor in the deterioration of the ecology. To address this issue, a considerable amount of municipal solid waste may be used to synthesise SiC nanomaterials from organic and inorganic fractions and use them as carbon and silica sources. Nanomaterials have progressively received widespread prominence as the development of particulate materials accelerates at an incredible rate. One such material is silicon carbide (SiC), which has garnered considerable interest due to its remarkable performance and wide variety of applications. This review article discusses the SiC pol-ytypes, including cubic, hexagonal, and rhombohedral SiC. The characteristics of silicon carbide, such as its biomimetic, surface, and thermal properties, are also discussed. In addition, the synthesis of silicon carbide was described in depth, including microwave sintering, the calcination method, the carbothermal redox reaction, and much more. The final section describes the applications of silicon carbide, including wastewater treatment, medical implants, and gas detection.
... The microhardness and Young's modulus of the coatings were measured in cross-sections using a scanning nanohardness tester Nanoscan 4D+ (TISNCM, Russia), described in detail in [15], according to the standardized Oliver and Pharr method [16]. An indenter in the form of a trihedral Berkovich diamond pyramid with an angle between the axis and a facet of 65 • was pressed into the surface of cross-section at a constant loading rate of 0.01 N/s until reaching the target load value of 0.1 N, followed by 3 s dwell time and an unloading time of 10 s. ...
This paper presents the results of the investigation of the microstructure and properties of copper‑tungsten coatings with different compositions on aluminum alloy substrates. Coatings were obtained by cold spray method using powder mixtures as feedstock. The effect of the powder mixture composition on the deposition efficiency and the tungsten content in the coating have been studied. X-ray diffraction analysis was used to investigate the phase composition and to reveal the peculiarities of changes in the crystalline structure of copper and tungsten particles after cold spraying in relation to the coating composition. Using the method of instrumental indentation on cross-sections of the coatings mechanical properties were measured. It was shown that increasing of tungsten content in the coatings contributes to increasing the microhardness and Young's modulus of the coatings. The mapping images showed that all coatings were characterized by non-uniformity of mechanical properties over the cross-section. The bonding strength of coatings significantly increases with increasing tungsten content in the feedstock. CuW coatings are characterized by lower specific wear rate values and higher coefficients of friction under dry sliding wear conditions in a ball-on-flat mode compared to pure copper coating.
It is experimentally shown that during laser annealing of micron layers of fluorocarbon oil by high-power KrF laser radiation pulses, C : F nanocoatings with a thickness of up to ~100 nm can be synthesised on a leucosapphire surface. The absorption spectra of these coatings, measured in the 0.19 – 6 μm range, virtually coincided with the absorption spectra of fluorographene in the quantum energy range of 5 ± 1 eV. The nanohardness and elasticity modulus of the C : F nanocoatings are found to be 7 and 250 GPa, respectively, which is close to the characteristics of fluorographene.
Novel C/SiC core-shell fibers have been synthesized through incomplete conversion of carbon fibers by their siliconization with SiO gas. The synthesis was performed in the laboratory-made semi-closed batch-type reactor at 1380 °C for 3 h using a 9:1 M ratio mixture of Si and SiO2 powders as a solid source of SiO gas. The conversion rate of carbon into SiC was 34.0%. All synthesized fibers had a distinct C/SiC core-shell composite structure. The fiber product was of fairly good uniformity in respect of the shell thickness which varied approximately from 0.6 μm to 0.8 μm depending on the location of fibers inside the reactor. It was revealed that the formation of the shell was the result of inward growth of the SiC product layer. The effectiveness of the proposed semi-closed reactor for the synthesis of C/SiC core-shell fibers has been demonstrated.
Generally, SBR and NBR are widely used in industrial as well as in automobile applications. The main aim of this research is to determine the mechanical properties and their behavior of SBR (Styrene Butadiene Rubber) and NBR (Nitrile Butadiene Rubber) blends mixed with silicon carbide (SiC – as filler) in different compositions. SBR and NBR sheets, and SiC powder are bought and the rubbers are mixed to form blends in order to enhance the properties. Mechanical properties such as tensile, tear, abrasion and resilience tests were conducted according to ASTM standards. Also, hardness was also measured, and properties of all samples were compared. Graphs were drawn to compare the results obtained. Enhancement in properties were obtained and noted.
Ceramic materials based on silicon carbide, SiC fibers reinforced were densely obtained by hot pressed at 1850°C. SiC fibers were obtained by siliconizing. Yttrium aluminum garnet (YAG) was used as an activating additive in an amount of 8 wt.%. The highest level of physical and mechanical properties was achieved ρ = 3,19±0,01 g/cm 3 ; δ = 571±33 MPa; К1С = 5,7±0,1 MPa•m 1/2 in the material reinforced with 5 wt.% SiC fibers.
The Crystallography Open Database (COD), which is a project that aims to gather all available inorganic, metal-organic and small organic molecule structural data in one database, is described. The database adopts an open-access model. The COD currently contains ∼80 000 entries in crystallographic information file format, with nearly full coverage of the International Union of Crystallography publications, and is growing in size and quality.
The literature on preparation methods and signature features of composites based on transition-metal carbides, nitrides, and borides; covalent compounds (SiC, Si3N4); and Al2O3 reinforced with fibers and whisker crystals is reviewed. The main properties of the fibers and whisker crystals are studied.
A textile material consisting of SiC fibers has been produced by siliciding carbon cloth in a gaseous SiO atmosphere. The reactive SiO source used was a mechanical mixture of silicon and silicon dioxide. The process was run at a temperature of 1400°C under dynamic vacuum. The results demonstrate the conceptual feasibility of using the process for producing SiC cloth reproducing the dimensions and shape of the parent carbon cloth.
The Nicalon SiC fibre offers the possibility of the development of composite materials for use above 1000° C. This study has compared two types of Nicalon fibre, one which was shown to be amorphous and the other microcrystalline with a SiC grain radius of 1.7 nm. Both fibres behaved in a brittle manner when tested in air and in argon up to 1300° C and their strengths fell above 1000° C. There were indications that new defects were created in the amorphous fibre when tested in air above 1000° C. The microstructural analysis showed that as well as SiC, both SiO2 and free carbon were present in both fibres. The segregations of free carbon had a mean radius of 2.0 nm in the amorphous fibre and were grouped into two populations of 1.5 and 2.2 nm in the microcrystalline fibre.
Polycarbosilane as the precursor of continuous SiC fibre was synthesized by thermal decomposition of polydimethylsilane. The structure of the polycarbosilane is concluded to be similar to that of polysilapropylene by the measurements of i.r. spectra, NMR spectra and chemical analyses. Its formation mechanisms are initially the formation of carbosilane by thermal decomposition of polydimethylsilane and then the increase in molecular weight by dehydrogenation-condensation of the carbosilane. Molecular structure and molecular weight distribution of the polycarbosilane depend on the reaction temperature.
To understand the service behaviour of SiC fibres, the effects of ambient environment and temperature on the microstructure, mechanical property and oxidation behaviour of these fibres were investigated. The result shows that, the surface of SiC fibres becomes rough after exposure in air from 973 to 1573 K due to the formation of small SiO2 particles, and a smooth SiO2 film will be formed on the SiC fibre at 1773 K. In Ar atmosphere, SiC fibres will change into clusters of large SiC crystals after heat treatment for 2 h at 2373 K. The tensile strength of SiC fibres decreased by 66 and 95% when the fibres were exposed at 1773 K for 5 min in air and 2373 K for 2 h in Ar, respectively. This degradation is associated with the evaporation of CO and SiO from the fibres as well as with SiC grain growth in the fibres.
Ceramic fibers are essential components of new high-temperature-resistant lightweight materials. The production routes of ceramic filament fibers are complex and in most cases polymeric components or structures are key factors for fiber spinning. Either organic polymers are used as additives in the spinning dopes for oxide ceramic fibers or inorganic polymers are the precursors for the production of non-oxide fibers. This paper gives an up-to-date overview about different ceramic fibers and the chemistry behind the fiber development and production.
Non-oxide ceramic fibers are of considerable interest due to the ability to combine the high performance, especially high temperature thermal and creep resistance, with the structural advantages of fibers including their use as reinforcements for metal (MMCs) and ceramic matrix composites (CMCs). In this paper the development of CVD SiC fibers and three generations of polymer derived SiC fibers over the past 50 years are discussed, illustrating the effect of fiber precursor and processing on the microstructure and physical properties of the non-oxide ceramic fibers. Additionally recent advances in research and development related to fibers from SiC and SiCN systems are presented with discussion of the current focus on reducing the costs of the fiber processing, while increasing their thermostructural stability.
Silicon carbide fiber/silicon carbide matrix composites have been specified in several recent fusion power plant design studies because of their high operating temperature (1000–1100 °C) and hence high energy conversion efficiencies. Radiation resistance of the β-phase of SiC, excellent high-temperature fracture, creep, corrosion and thermal shock resistance and safety advantages arising from low induced radioactivity and afterheat are all positive attributes favoring the selection of SiCf/SiC composites. With the promise of these materials comes a number of challenges such as their thermal conductivity, radiation stability, gaseous transmutation rates, hermetic behavior and joining technology. Recent advances have been made in understanding radiation damage in SiC at the fundamental level through MD simulations of displacement cascades. Radiation stability of composites made with the advanced fibers of Nicalon Type S and the UBE Tyranno SA, where no change in strength was observed up to 10 dpa at 800 °C, in the development of materials with improved thermal conductivity, modeling of thermal conductivity, joining techniques and models for life-prediction. High transmutation rates of C and Si to form H, He, Mg, and Al continue to be a concern.
The properties and behaviour of single Nicalon (silicon carbide) fibres have been studied at temperatures of up to 1600 degrees C. A rapid decrease in strength was observed above 1000 degrees C. Creep rate measurements showed that a two-stage process was operative. The initial creep rate is found to depend on temperature and this is thought to be due to the recrystallization process. This stage lasted for 20 hr at all the temperatures investigated above 1000 degrees C and was followed by an increased creep rate stage involving defect migration until fracture.
MUCH work has been done on preparing heat-resistant silicon carbide materials in fibrous form, since plastics or metals can be reinforced with them to obtain very heat-resistant material of great mechanical strength. SiC whiskers1 are, however, impractical because of their shortness (several mm), their non-uniform diameter and high cost of production. SiC-on-W (ref. 2) and SiC-on-C (ref. 3) filaments have been produced by chemical vapour methods. These coated filaments are more expensive, and the treatment for making such composite materials requires careful control. We report here on the synthesis of continuous β-SiC fibres by a new process: the conversion of organometallic polymers to inorganic substances. We have studied the transformation process and the structure and mechanical properties of these fibres.
The rate of oxidation of silicon carbide was measured in an atmosphere of dry oxygen between 900° and 1600°C. The rate was studied by using a thermogravimetric apparatus and was found to be diffusion controlled. The products of oxidation were amorphous silica and cristobalite, depending on the temperature. The effect of surface area was determined, and a correlation between the various sizes was made with the aid of an equation derived on the assumptions that (1) the reaction was diffusion controlled, (2) the particles were essentially spherical, and (3) the interfacial area was constantly changing. The presence of water vapor in the gaseous atmosphere was found to be extremely critical.
C/SiC and SiC/SiC composites are tough ceramics when the fiber–matrix bonding is properly optimized, usually through a thin layer of an interfacial material referred to as the interphase. These composites can be fabricated by a variety of techniques that are briefly described and compared. The design of the interphase, matrix, and coating at the nanometer scale, in order to promote microcrack deflection and to enhance the oxidation resistance is discussed. Selected properties of the composites are presented and discussed. Examples of application in engines, heat shields, braking systems, and high-temperature nuclear reactors are shown to illustrate the potential of these materials and the key points that still require research and development.
The manufacture and characteristics of different families and generations of carbon-carbon and ceramic-matrix composites (CMC) were discussed. The composites were suitable for the production of parts when subjected to high mechanical stress and operating at very high temperatures in non-oxidizing and oxidizing environments. The first worldwide flight experiments of CMC components with the M88-2 engine, and with the certification and mass production of the CMC nozzle outer flaps were also elaborated.
The Nicalon silicon carbide fibre has been studied by X-ray photoelectron spectroscopy. Elements entering the fibre are carbon, silicon and oxygen. In addition to previously reported chemical entities (silicon carbide, silica and graphitic carbon) evidence is found of the presence of a new supplementary phase which is attributed to an intermediate silicon oxycarbide phase. As this phase is found to participate in very appreciable proportions to the composition of the fibre, some influence on the properties of this fibre can be anticipated.
Polycarbosilane as the precursor of continuous SiC fibre was synthesized by thermal decomposition of polydimethylsilane. The
structure of the polycarbosilane is concluded to be similar to that of polysilapropylene by the measurements of i.r. spectra,
NMR spectra and chemical analyses. Its formation mechanisms are initially the formation of carbosilane by thermal decomposition
of polydimethylsilane and then the increase in molecular weight by dehydrogenation-condensation of the carbosilane. Molecular
structure and molecular weight distribution of the polycarbosilane depend on the reaction temperature.
Three generations of small diameter ceramic fibres based on polycrystalline silicon carbide have been developed over a period
of thirty years. This has been possible due to studies into the relationships between the microstructures and properties of
the fibres. A variety of techniques have been employed by research teams on three continents. The fibres are made by the conversion
of polymer precursors to ceramic fibres and all three generations are presently produced commercially. The nature of the precursor
and the techniques used for cross-linking have been varied in order to optimise both properties and cost of manufacture. It
has been possible to improve the characteristics of the fibres as the processes involved in the cross-linking of the precursor
fibres have been better understood and the mechanisms governing both room temperature and high temperature behaviour determined.
The result is that, although first generation fibres were limited by a low Young's modulus at room temperature and by creep
and instability of the structure at temperatures far lower than those limiting the behaviour of bulk silicon carbide, the
third generation fibres shows many of the characteristics of stoichiometric silicon carbide. This remarkable improvement in
characteristics has been due to a thorough understanding of the materials science governing the behaviour of these fibres
which are reinforcements for ceramic matrix composite materials.
Activated carbon fiber composites (ACFCs) with the specific surface area of about 1150 m2/g were reacted to produce silicon carbide fiber composites with SiO vapor generated from a mixture of Si and SiO2 at 1673 K under vacuum for various hold times ranging between 10–120 min. Chemical analysis of the converted ACFCs resulting from reaction showed that the products contained 79–90 wt.% silicon carbide, 7–13 wt.% amorphous silica and 3–8 wt.% unreacted carbon, and the composition depended on hold time. At an early stage of the SiO–C reaction during hold time, part of the excess SiO vapor generated was presumed to condense on to the converted fiber surface as amorphous silica, thereby reducing the specific surface area of the converted ACFCs. As the C–SiC conversion proceeded, the gas-phase carbon reduction of SiO2 with CO occurred and increased the specific surface area from 25 m2/g to 48 m2/g. Strength of the converted ACFCs decreased with conversion due to the increased specific surface area and crack formation in the converted carbon fiber.
Silicon carbide fibers were prepared by the reaction between activated carbon fibers and silicon monoxide generated from a mixture of silicon and silicon dioxide at temperatures from 1200 to 1300°C in an inert atmosphere of argon. The reaction was completed at temperatures as low as 1200°C, which means that activated carbon fibers had a high reactivity. The resulting sample maintained the original morphology of the starting material, which was an advantage because of the difficulty in post shaping silicon carbide, and led to a silicon carbide fiber with high specific surface area. The resulting samples were characterized by powder X-ray diffraction, thermal gravimetric analysis, and by nitrogen adsorption measurements at 77.4 K to obtain surface area and pore size distributions. The morphology of the resulting sample was observed by scanning electron microscopy and the electronic structure was investigated by Fourier transformation infrared spectroscopy and X-ray photoelectron spectroscopy techniques.
High-temperature ceramic material of SiC–SiC type for use in heat-loaded parts of advanced propulsion systems
- Grashchenkov
Prospects of using SiC/SiC composites in fusion reactors (from the analysis of international data-bases INIS, MSCI, INSPEC)//problems of atomic sci-ence and technology
- Voitsenya
Preparation of silicon carbide fiber from activated carbon fiber and gaseous silicon monoxide
- Okada
Synthesis of continuous silicon carbide fibre
- Hasegawa