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In this study, a novel friction material with biomass-ceramic (SiC) dual matrixes was fabricated using Chinese fir pyrocarbon via the liquid-phase silicon infiltration and in situ growth method. SiC can be grown in situ on the surface of a carbonized wood cell wall by mixing and calcination of wood and Si powder. The samples were characterized using XRD, SEM, and SEM–EDS analysis. Meanwhile, their friction coefficients and wear rates were tested to study their frictional properties. To explore the influence of crucial factors on friction performance, response surface analysis was also conducted to optimize the preparation process. The results showed that longitudinally crossed and disordered SiC nanowhiskers were grown on the carbonized wood cell wall, which could enhance the strength of SiC. The designed biomass-ceramic material had satisfying friction coefficients and low wear rates. The response surface analysis results indicate that the optimal process could be determined (carbon to silicon ratio of 3:7, reaction temperature of 1600 °C, and 5% adhesive dosage). Biomass-ceramic materials utilizing Chinese fir pyrocarbon could display great promise to potentially replace the current iron–copper-based alloy materials used in brake systems. [ABSTRACT FROM AUTHOR]

Initial powders of Zr, Al, C and Zr, Al, ZrC were used for the synthesis of MAX phases of the compositions Zr2AlC and Zr3AlC2. The highest content (50.4 vol %) of the MAX phase Zr3AlC2 was obtained using the initial powders Zr/Al/ZrC in the ratio of components 1 : 1.5 : 2 with the addition of 5 vol % of Al. The optimal temperature for the synthesis of a material based on the MAX phase Zr2AlC is 1525°C, and that of the material based on Zr3AlC2—1575°C. The structure of the synthesized MAX materials includes elongated grains of the compositions Zr2AlC and Zr3AlC2, which determines their high strength. Zirconium carbide, as an intermediate phase, is always present in the final products. Due to the considerable evaporation of aluminum, the ZrO2 phase is also present in the synthesis products. Excess aluminum contributes to the maximal formation of Zr2AlC and Zr3AlC2 phases during synthesis. [ABSTRACT FROM AUTHOR]

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 polytypes, 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. [ABSTRACT FROM AUTHOR]

This paper reports on vacuum carbosilicothermic reduction of zirconium(IV), hafnium(IV), vanadium(V), niobium(V), tantalum(V), and chromium(III) oxides at a temperature of 1600°C, using silicon carbide as a reducing agent. It has been shown that the only phase resulting from the reduction of hafnium oxide is hafnium carbide. The reduction of chromium and vanadium oxides yields only chromium silicide and vanadium silicides, respectively. The reduction of zirconium, niobium, and tantalum oxides leads to the formation of carbides and silicides of the respective metals. No ternary compounds similar to MAX phases have been obtained. [ABSTRACT FROM AUTHOR]

We have studied the desilicidation of Ti3SiC2 MAX phase powder at 1600°C in a CO + xSiO (x = 0, 1, 1.5, 2, 3) gas atmosphere. The required gaseous atmosphere was generated using granulated powder mixtures containing commercial carbon, TiO2, SiO2, and SiC, which released CO and SiO gases during heating as a result of oxide reduction reactions. Ti3SiC2 desilicidation was sensitive to the gas phase composition and occurred only if the CO : SiO ratio exceeded 1 : 3 (x < 3). The Ti3SiC2 desilicidation process was shown to be reverse of TiC silicidation with SiO gas and could be described by the following chemical reaction scheme: Ti3SiC2 + CO(g) = 3TiC + SiO(g). [ABSTRACT FROM AUTHOR]

Technologically viable principles have been developed for the preparation of the MAX phase Ti3SiC2 by self-propagating high-temperature synthesis (SHS) with a reduction step, using titanium dioxide. We have studied the influence of synthesis conditions (starting-mixture composition and ratio of reactants) on the composition, structure, and particle size of the Ti3SiC2 powder. The results demonstrate that the addition of 10 to 20 wt % excess magnesium to the starting mixture leads to a decrease in the percentage of the TiSi2 and Ti5Si3 silicides in the Ti3SiC2 powder (from 8 to 5 wt %), with the smallest percentage of titanium carbide corresponding to a 10% excess of magnesium in the starting mixture. Raising the amount of silicon in the starting mixture by 10% leads to a decrease in the percentages of the TiSi2 and Ti5Si3 silicides and titanium carbide in the Ti3SiC2 powder. The addition of sodium chloride and magnesium perchlorate to the starting mixture has been shown to influence the percentages of the TiSi2 and Ti5Si3 silicides and TiC in the Ti3SiC2 powder. We have optimized conditions for the synthesis of powder containing 89.1 wt % Ti3SiC2. The powders prepared by SHS with a reduction step consist of agglomerates of layered particles ranging in size from 130 to 770 nm. [ABSTRACT FROM AUTHOR]

Dense silicon carbide-based ceramic composites reinforced with SiCf fiber have been produced by hot pressing at a temperature of 1850°C. The reinforcing agent used was silicon carbide fiber produced by siliciding carbon cloth with SiO vapor. It has been shown that raising fiber content from 1 to 7 wt % increases the density, bending strength, and fracture toughness of the material, which reach ρ = 3.20 ± 0.01 g/cm3, δb = 450 ± 26 MPa, KIс = 5.6 ± 0.1 MPa m1/2 at 7 wt % SiC fiber. [ABSTRACT FROM AUTHOR]

The dependence of the phase composition and parameters of a fine structure of titanium silicon carbide in powders formed by the self-propagating high-temperature synthesis on the aluminum concentration in the 5Ti/2Si/1C reaction mixture is investigated. The aluminum content is varied in a range of 0.1–0.4 mole fraction with the conservation of the total carbon content. It is established that the additives of aluminum not only affect the yield of titanium silicon carbide, but also promote the preferential formation of Ti5Si3 in synthesis products instead of TiSi2 identified in powders containing no aluminum. The introduction of a small amount of aluminum (0.1 mole fraction) leads to the formation of the Ti3Si1 – xAlxC2 solid solution and makes it possible to decrease the content of impurity phases in SHS powders by 6%. The silicon carbide concentration in SHS powders decrease at a higher aluminum content in the reaction mixture, while that of binary compounds (TiC, Ti5Si3, TiAl) correspondingly increases. No noticeable effect from the introduction of aluminum on the parameters of the crystal lattice of titanium silicon carbide in SHS powders is found in concentration limits of 0.1–0.25 mol %. A noticeable increase in parameters of a and c for Ti3Si1 – xAlxC2 (from a = 3.067 Å, c = 17.67 Å to a = 3.07 Å, c = 17.73 Å) with the conservation of the c/a ratio in limits of known values (c/a = 5.78) is observed only with the aluminum concentration of 0.4 mole fraction. The crystallite size of titanium silicon carbide depends, first and foremost, on the combustion parameters. At the same time, the deformation of the crystal lattice of Ti3Si1 – xAlxC2 in SHS powders increases monotonically with an increase in the aluminum content in the reaction mixture in the concentration range under study. [ABSTRACT FROM AUTHOR]

Materials based on the titanium carbosilicide Ti3SiC2 (MAX phase), prepared by spark plasma sintering (SPS), have been subjected to high-temperature tests. The high-temperature behavior of samples containing the carbosilicide phase and carbosilicide-free samples were studied. The results demonstrate that the presence of the MAX phase improves the heat resistance of the material, preventing oxidation. The oxidation products of the titanium carbosilicide-based materials are titanium dioxide, silicon monoxide, and carbon dioxide. [ABSTRACT FROM AUTHOR]

composite material (CM) based on titanium carbosilicide with a titanium carbide content of 50% possessing a microcrystalline structure is obtained by mechanosynthesis in a planetary mill with subsequent hot pressing. The highly nonequilibrium structure of the powder material, which forms due to the high-energy treatment, makes it possible to obtain material with a relative density of 96% at a hot-pressing temperature of 1400°C and a pressure of 20 MPa. Comparative tests of the CM and silicon carbide for wear resistance under different conditions are carried out. The CM based on titanium carbosilicide showed less wear of the counterbody and a lower friction coefficient in all cases. However, in tests using an abrasive medium, wear of the composite material itself is observed. [ABSTRACT FROM AUTHOR]

Phase relations in the Ti-C-SiC system are studied with the aim of optimizing Ti3SiC2 synthesis. The optimal starting-mixture compositions for the synthesis of phase-pure Ti3SiC2 powder can be represented by the formula 3Ti + (1 − z)C + (1 + z)SiC, where z = 0.2–0.6. In the temperature range 1630–1670 K under dynamic vacuum, the excess silicon vaporizes from the sample. The processes leading to the formation of impurity phases are discussed. [ABSTRACT FROM AUTHOR]

Comprehensive studies of the flaw level and some structural characteristics of a composite ceramic material based on Karakeche clay (Kyrgyzstan) are carried out for a range of thermoactivation regimes and impurity contents of silicone carbides of various types. [ABSTRACT FROM AUTHOR]

The biomorphic Silicon Carbide (BioSiC) ceramic with highly interconnected porous three-dimensional (3D) structure was fabricated by utilizing balsa wood cellulose nanofibers aerogel as the biotemplate and polycarbosilane (PCS) as the preceramic precursor. Evolution of morphology, composition, and pore properties from untreated wood to porous BioSiC was investigated systemically. The shrinkage and weight gain during pyrolysis was discussed. It was found that the structure of as-synthesized BioSiC was related to the microstructure of wood aerogel template and the concentration of PCS precursor. The proper microstructure of cellulose skeleton which was essential for the infiltration process could obtained by removing lignin and hemicellulose appropriately. The optimum PCS content was 40 wt. % for easy infiltration and proper SiC content. The results revealed that the dredged skeleton of cellulose was reproduced perfectly by PCS ceramization. The obtained BioSiC presented high porosity (61.03%) and low density (0.86 g/cm3) with good Darcy permeability (19.22 mD). [ABSTRACT FROM AUTHOR]