Incorporation Of SiC Research Articles

Regulating the metabolites through SiC, ZnO, and SnO2 nano-photocatalysts for elevating efficiency of photo fermentative bioH2 from Arundo donax L.

Photo-fermentation offers a promising roadmap for hydrogen production through their ability to harness light energy, however, its lower conversion efficiency is the major bottleneck for its realization. This study investigates the catalytic role of wideband gap nano-photocatalysts (SiC, ZnO, and SnO2) in enhancing hydrogen generation from Arundo donax L. Physio-optical characteristics of SiC, ZnO, and SnO2 nano-photocatalysts were assessed through SEM, XRD, and FT-IR which confirmed that incorporated nano-photocatalysts are spherical with uniform size distribution and there is no secondary phase. Hydrogen production experiments with varying nano-photocatalyst concentrations revealed that the maximum hydrogen yield of 104 and 98.83 mL/g was achieved with SiC and ZnO, respectively, at loading concentration of 200 mg/L, whereas 69.30 mL/g were observed with 100 mg/L of SnO2. The incorporation of SIC, ZnO, and SnO2 nano-photocatalyst permitted to increase the hydrogen content in overall gas production by 41 %, 37.34 %, and 18.26 % as compared to the control group. The increase in hydrogen production is related to the enhanced e-h pair separation lifetime of SiC, confirmed from PL spectroscopy. Addition of SiC caused a longer availability of electrons that helped to increase the metabolic rate by 38 % and 40.29 % in energy conversion efficiency (ECE). ANOVA results revealed significant differences between the control and maximum values of CHP, HC%, byproducts, and ECE. Tukey pairwise comparisons showed that SiC and ZnO had non-significant differences at 200 mg/L but both significantly outperformed SnO2 at 100 mg/L. Thus, the selection of suitable catalysts photocatalysts with enhanced e-h pair separation lifetime may offer promising prospects for sustainable energy technologies by enhancing biohydrogen production.

Effect of varying temperature on sintering SiC/B4C reinforced Al6061 alloy composites using vacuum sintering method

The current investigation involved the fabrication of Al6061/SiC/B4C composites with different sintering temperatures using the vacuum casting technique. The morphology and mechanical properties of these composites were then analyzed and are summarized. Morphology studies show that increasing the sintering temperature leads to notable grain refinement, even distribution of reinforcement, and minimal porosity. The incorporation of SiC and boron carbide particles into the matrix enhanced the hardness of 18.37% of the composites by serving as a hindrance to the movement of the matrix lattice dislocations. An increase in sintering temperature results in greater plastic deformation of composites, hence cracks formed and propagated easily due to their brittle nature ultimately reducing the impact strength of composites. The robust adhesion between the Al6061 matrix and the SIC and boron carbide particulates in particle-reinforced composites efficiently inhibited delamination and decreased the rate of wear composites.

Research on NaCl-KCl High-Temperature Thermal Storage Composite Phase Change Material Based on Modified Blast Furnace Slag

The high-temperature composite phase change materials (HCPCMs) were prepared from solid waste blast furnace slag (BFS) and NaCl-KCl binary eutectic salt to achieve efficient and cost-effective utilization. To ensure good chemical compatibility with chlorine salt, modifier fly ash (FA) was incorporated and subjected to high-temperature treatment for the processing of industrial solid waste BFS, which possesses a complex chemical composition. The HCPCMs were synthesized through a three-step process involving static melting, solid waste modification, and mixing–cold pressing–sintering. Then, the influence of the modification method and the amount of SiC thermal conductivity reinforced material on chemical compatibility and thermodynamic performance was explored. The results demonstrate that the predominant phase of the modified solid waste is Ca2Al2SiO7, which exhibits excellent chemical compatibility with chlorine salt. HCPCMs containing less than 50 wt.% chloride content exhibit good morphological stability without any cracks, with a melting temperature of 661.76 °C and an enthalpy value of 108.73 J/g. Even after undergoing 60 thermal cycles, they maintain good chemical compatibility, with leakage rates for melting and solidification enthalpies being only 6.3% and 0.23%, respectively. The equilibrium was achieved when 40 wt.% of chloride salt was encapsulated upon the addition of 10% of SiC, and the incorporation of SiC resulted in an enhancement of thermal conductivity for HCPCMs to 2.959 W/(m·K) at room temperature and 2.400 W/(m·K) at 200 °C, with an average increase of about 2 times. The cost of the prepared HCPCMs experienced a significant reduction of 81.3%, demonstrating favorable economic performance and promising prospects for application. The research findings presented in this article can offer significant insights into the efficient utilization of solid waste.

Incorporation of SiC on the mechanical properties, tribological performance, and oxidation resistance of HfC-SiC/a-C:H coatings prepared by hybrid HiPIMS and pulsed-DC magnetron co-sputtering

The multiphase nanocomposite HfC-SiC/a-C:H coatings consisting of HfC and SiC grains dispersed in the amorphous carbon matrix were deposited by hybrid HiPIMS and pulsed-DC magnetron co-sputtering. The incorporation of SiC ranging from 0 to 21.3 at.% on the chemical bonding state, nanocomposite structure, mechanical and tribological properties, and oxidation resistance of the coatings were explored. Results showed that the increase of SiC content is mainly at the expense of a-C:H matrix rather than nanocrystalline HfC, and is accompanied by changes in the HfC crystallinity. Nanohardness of up to 45 GPa was obtained for the HfC-SiC/a-C:H coating with 6.6 at.% SiC content. The optimum wear rate of 6.4×10−7mm3/N and friction coefficient of 0.2 were also obtained at 6.6 at.% SiC content. The oxidation resistance is enhanced with the increase of SiC content, which delays the oxidation temperature by 100 °C with respect to the HfC/a-C:H coating.

Microstructure, texture, and mechanical properties analysis of novel AA7178/SiC nanocomposites

The current research aims to use stir casting to create a composite made from AA7178 aluminium alloy with nano SiC reinforcement at 1, 2, and 3 wt percent. Scanning electron microscope (SEM) with energy dispersive X-Ray (EDAX) was used to examine the microstructural changes of AA7178/nSiC composites. The addition of nano SiC reinforcement to the AA7178 matrix promotes grain refinement by providing additional nucleation sites for smaller grains to form. The microstructure of AA7178 composites underwent a considerable alteration due to the SiC addition, improving their mechanical properties. Electron backscatter diffraction (EBSD) study revealed the development of finer grains from coarser grains. All the samples seemed to have a completely random texture. The texture does not seem to be drastically altered by either the processing conditions or the incorporation of SiC. The uniform distribution of SiC particles and good interfacial bonding between the reinforcement matrix was confirmed by a transmission electron microscope (TEM). The maximum tensile strength was 206.12 MPa for AA7178 nanocomposite with 3 wt% of SiC reinforcement. The efficient transmission of load and dislocation strengthening were the strengthening mechanism for increasing in the tensile strength. The inclusion of 3 wt% of SiC particles increased the hardness of AA7178 nanocomposite to 51.70%.

Characteristics of Al6061-SiC-Al2O3 Surface Hybrid Composites Fabricated by Friction Stir Processing

Friction stir processing (FSP) has successfully evolved as an alternative technique of fabricating metal matrix composites. (MMC). FSP has been used positively to produce surface composite that offer good surface properties such as higher hardness and wear resistance, also help in the development of finer-grain structure during thermomechanical processing of the material. This work aims to fabricate a surface composite upon the AA6061-T6 Al alloy via FSP. The effect of SiC and/or Al2O3 particles on microstructure, microhardness, and wear behavior of the surface composite was investigated. Many drilled holes were made to incorporate the ceramic particles within the matrix at the optimal friction stir processing circumstances, The optimal parameters of (FSP) were (32 mm ̸min), (1250 rpm), and (2) passes in a similar track.. It was obtained that the maximum microhardness being in the stir zone center of FSP of the base alloy and all composites. The results of XRD and EDX mapping confirmed the incorporation of SiC and Al2O3 particles within the surface of Al alloy using FSP which will improve the surface properties. The improvement in microhardness was (89.3%) in the case of FSP composite sample reinforced with hybrid addition (SiC+Al2O3) particles in comparison to FSP unreinforced base alloy (75 HV). It was showed that the wear resistance of the FSP composite sample reinforced with hybrid addition of (Al2O3 and SiC ) particles was slightly better than that of the FSP composite sample reinforced with single Al2O3 or SiC particles and base Al alloy.

Effect of co-addition of SiC and WC on the densification behaviour and microstructural evolution of TiC-based composites

In the present study, the effect of simultaneous incorporation of SiC and WC additives on the densification behaviour and microstructural development of TiC-based composites is studied. Four different TiC-SiC-WC (TSW) composites with varying SiC and WC content were synthesized by ultrasonic wet milling followed by spark plasma sintering (SPS) at 1750 °C for 5 min under 40 MPa external pressure. The average particle size of the ultrasonic wet-milled mixture underwent an appreciable refinement from 2.48 μm (un-milled powder) to between 0.9 and 1.25 μm. The sintered compacts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermodynamic assessment. All TSW sintered specimens exhibited a relative density of greater than 98% with TiC +10 wt% SiC +15 wt% WC reaching the highest value of 99.2%. The XRD analysis and microstructural evaluation confirmed the in-situ formation of Ti3SiC2 compound for specimens TiC +15 wt% SiC +10 wt% WC and TiC +20 wt% SiC +5 wt% WC as suggested by the thermodynamic evaluation. Besides, except for specimen TiC +20 wt% SiC +5 wt% WC, some of the SiC grains with unclean grain boundaries were found to be dissolved partially within the (Ti, W) C solid solution, thereby indicating the formation of (Ti, W, Si) C solid solutions as confirmed by the SEM/EDS analysis. The optimum hardness and indentation fracture toughness of 22.43 GPa and 6.54 MPa m½ were obtained for the samples TS10W15 and TS15W10, respectively. Crack deflection, branching, and bridging induced by the untwine SiC grains, partly un-dissolved WC particles, and (Ti, W) C solid solution phase are among the main toughening mechanisms responsible for improving the fracture toughness of the co-reinforced specimens besides the break of intertwining SiC grains.

Physical, Corrosion and Microstructural Analysis of A356/SiC Nanocomposites Fabricated through Stir Casting Process

Porosity is one of the main difficulty to fabricate the superior quality of aluminium matrix composites (AMCs) because it effects the surface finish of the casting, mechanical properties and corrosion resistance. Therefore, porosity must be minimum as possible so that better casting can be produced with optimal properties of the composites. In this study, aluminium matrix nanocomposites (A356/SiC or AMNCs) were fabricated through two-step stir casting via mechanical alloying using ball mill. The matrix alloy (A356) was reinforced with SiC nanoparticles of 40-55 nm avarage particle size (APS). The corrosion was performed by simple immersion corrosion test method for a predefined environment (3.5% NaCl solution) and for the specified duration. The results showed that density and porosity increase with the addition of reinforcement. The corrosion resistance get reduced with the incorporation of SiC due to the increase in porosity and number of nucleation sites. The substantial correlation between the corrosion rate and the amount of SiC are depicted. Moreover, the corrosion rate decreased with the increase in exposure time which is due to the formation of passive layer. The EDS spectrum shows the presence of different constituents in the composites. The formation of the cracks, oxides, pitting corrosion, and localized corrosion are found by the SEM results. Further, SEM of the corroded surface verifies the presence and good distribution of the SiC nanoparticles in the fabricated nanocomposites.

Controllable dielectric properties and strong electromagnetic wave absorption properties of SiC/spherical graphite-AlN microwave-attenuating composite ceramics

Fully dense SiC/spherical graphite-AlN microwave-attenuating composite ceramics were manufactured via hot-pressing sintering, in which, apart from the primary SG (spherical graphite) attenuating agent, 5–30 wt% semiconductive α-SiC was employed as the second attenuating agent. The incorporation of SiC contributed to a slightly decreasing electrical conductivity and enhanced polarization relaxation. Controllable complex permittivities were obtained, namely, both the real and imaginary permittivities exhibit first a decrease and then an increase with the SiC addition, and which delivers an optimized impedance matching of the composites. RLmin values below −10 dB (more than 90% absorption) were achieved by all the composites containing 5–20 wt% SiC with the sample thickness of 1–1.4 mm, and the absorption performance characteristics were significantly tunable by controlling the of SiC content at 8.2–12.4 GHz. Impressively, a superior reflection loss of −46 dB (1.1 mm) and wide effective absorption bandwidth of 2.1 GHz were achieved at a 5 wt% SiC content, respectively, rendering SiC/SG–AlN composites a potential ultra-thin and highly efficient microwave-attenuating ceramic candidate.

Effect of Different Reinforced Metal-Matrix Composites on Mechanical and Fracture Behaviour of Aluminium Piston Alloy

Al-Si10Cu2Fe and Al-Si12Cu aluminium alloy composites were fabricated by using various weight percentage of SiC and TiB2 reinforcement particles in a two-step stir-casting process to improve their corrosion resistance for use in transport, aerospace and marine industries. Morphological and microstructural analysis of the composites were carried out using field-emission scanning electron microscopy and energy dispersive X-ray spectrometry, respectively. The results indicated a homogeneous distribution of the SiC and TiB2 particles in the matrix, resulting in enhanced materials with better mechanical properties. The improvement of the tensile strength and elastic modulus for Al-Si12Cu–7%TiB2 was 73% and 15.3%, respectively, as compared with the Al-Si10Cu2Fe matrix alloy. The uniform incorporation of SiC and TiB2 microparticles increases the bonding strength with the matrix and improves the hardness. These properties are useful to improve the tribological behaviour.

Electrochemical tailoring of Pb-free Sn coatings modified with SiC nanoparticles by surfactant-assisted reverse pulse plating

In this study, reverse pulse plating technique was used to study the effect of various surfactants (anionic, non-ionic, and cationic) in electrolytes and incorporation of SiC nanoparticles (NPs) in the Sn matrix. The microstructural and electrochemical observations indicate that the incorporation of SiC in Sn coating depends upon the type of surfactants. The composite stress moves from compressive to tensile with SiC content. The maximum grain refinement of Sn-SiC coatings was found in the presence of a cationic surfactant in the electrolyte while a minimum value of resistivity was displayed by coatings prepared in anionic surfactant. The corrosion behavior of Sn-SiC coatings showed superior corrosion protection ability of non-ionic surfactants amongst other surfactants used here.

Influence of SiC and TiC nanoparticles reinforcement on the microstructure, tribological, and scratch resistance behavior of electroless Ni–P coatings

Two different ceramic carbide nanoparticles (SiC, and TiC) were separately incorporated into the Ni–P matrix via the electroless deposition method. As prepared Ni–P, Ni–P–SiC, and Ni–P–TiC coatings were subjected to heat treatment at 400 °C for 1 h. The surface morphology, microstructural transformation, Vicker’s microhardness, tribological and scratch resistance properties were studied with reference to the different carbide reinforcements as well as heat treatment. Inter-nodular space, craters and kinks are created due to the branching effect of nodules in the surface of the Ni–P–SiC (TiC) composite coatings. After the heat treatment, the matrix phase transformation was not altered due to the incorporation of SiC or TiC into the Ni–P coating; however, a slight increase in residual stress was identified from the XRD analysis. In addition, the content of carbon deposition was found to be higher in the matrix of Ni–P–SiC composite coating than that in the Ni–P–TiC coating. The agglomeration of SiC particles was higher than TiC particles in the coating matrix, which was also supported by the result of Zeta potential measurement. Heat treatment improved wear and coefficient of friction in the Ni–P–SiC and Ni–P–TiC composite coatings. Compared to Ni–P–SiC coating, Ni–P–TiC coating revealed the enhanced tribological and scratch resistance performance after the heat treatment.

Effect of milling time on the compressive high strain rate behavior of Al-SiC Composite

Aluminum-Silicon carbide (Al-SiC) metal matrix composite (MMC) have gained importance as a new class of material capable of serving the future generation brake material requirements. The presented study deals with the compressive high strain rate behavior of Al-SiC composite comprising 15% SiC by weight. The MMC specimens were fabricated by powder metallurgy route. Three different ball milling times were selected for the study purpose after optimizing all other processing parameters. Incorporation of SiC invariably enhanced the hardness, quasi-static and dynamic compressive strength of Al-SiC composite. Hardness was noted to enhance as a function of increasing ball milling time. However, the quasi-static and dynamic compression properties were recorded highest for the ball milling time of 240 minutes. The study confirms that minor addition of a suitable reinforcing material can significantly improve the properties of an MMC. Also, increasing the ball mill time may not necessarily enhance all the material properties.

Effects of SiC and SiC-GNP additions on the mechanical properties and oxidation behavior of NbB2

ABSTRACTMonolithic NbB2, NbB2-SiC, and NbB2-SiC-GNP samples were produced by spark plasma sintering (SPS), and the effects of additives on the mechanical and thermal properties, microstructures, and oxidation behavior of the samples were investigated. The addition of SiC up to 30 vol% decreased the Vickers hardness of the binary composites due to microcrack formation. The fracture toughness and oxidation resistance of NbB2 were improved with the incorporation of SiC. Fracture toughness was higher for all the composites in comparison to monolithic NbB2, moreover the highest value of ~5.2 MPa·m1/2 exhibited by 3 vol% GNP-containing composite. A strong interface and homogeneous distribution of GNPs enhanced the thermal transfer properties and improved the oxidation resistance of selected NbB2-SiC ceramics in oxidation studies at 1200°C. A combination of high mechanical properties, high thermal conductivity, and low mass gain was achieved for the NbB2-SiC-GNP samples with 1 and 3 vol% GNPs.

Spark Plasma Sintering of High-Energy Ball-Milled ZrB<sub>2</sub> and HfB<sub>2</sub> Powders with 20vol% SiC

ZrB2 and HfB2 with incorporation of SiC are being considered as structural materials for elevated temperature applications. We used high energy ball milling of micron-size powders to increase lattice distortion enhanced inter-diffusion to get uniform distribution of SiC and reduce grain growth during Spark Plasma Sintering (SPS). High-energy planetary ball milling was performed on ZrB2 or HfB2 with 20vol% SiC powders for 24 and 48 hrs. The particle size distribution and crystal micro-strain were examined using Dynamic Light Scattering Technique and x-ray diffraction (XRD), respectively. XRD spectra were analyzed using Williamson-Hall plots to estimate the crystal micro-strain. The particle size decreased, and the crystal micro-strain increased with the increasing ball milling time. The SPS consolidation was performed at 32 MPa and 2,000°C. The SEM observation showed a tremendous decrease in SiC segregation and a reduction in grain size due to high energy ball milling of the precursor powders. Flexural strength of the SPS consolidated composites were studied using Four-Point Bend Beam test, and the micro-hardness was measured using Vickers micro-indenter with 1,000 gf load. Good correlation is observed in SPS consolidated ZrB2+SiC with increased micro-strain as the ball milling time increased: grain size decreased (from 9.7 to 3.2 μm), flexural strength (from 54 to 426 MPa) and micro-hardness (from 1528 to 1952 VHN) increased. The correlation is less evident in HfB2+SiC composites, especially in micro-hardness which showed a decrease with increasing ball milling time.

Pursuing enhanced oxidation resistance of ZrB2 ceramics by SiC and WC co-doping

The oxidative degradation of ZrB2 ceramics is the main challenge for its extensive application under high temperature condition. Here, we report an effective method for co-doping suitable compounds into ZrB2 in order to significantly improve its anti-oxidation performance. The incorporation of SiC and WC into ZrB2 matrix is achieved using spark plasma sintering (SPS) at 1800 °C. The oxidation behavior of ZrB2-based ceramics is investigated in the temperature range of 1000 °C–1600 °C. The oxidation resistance of single SiC-doped ZrB2 ceramics is improved due to the formation of silica layer on the surface of the ceramics. As for the WC-doped ZrB2, a dense ZrO2 layer is formed which enhances the oxidation resistance. Notably, the SiC and WC co-doped ZrB2 ceramics with relative density of almost 100% exhibit the lowest oxidation weight gain in the process of oxidation treatment. Consequently, the co-doped ZrB2 ceramics have the highest oxidation resistance among all the samples.

Polymer-derived ceramic tapes with small and negative thermal expansion coefficients

A polysiloxane filled with ß-eucryptite and/or SiC was used for the processing of polymer derived ceramic tapes. The combination of both fillers in varying proportions allowed to tailor the overall bulk thermal expansion and the flexural strength of the resulting composite materials simultaneously. Incorporation of SiC increased noticeably the flexural strength of the samples and influenced the phase changes resulting from the interactions between the β-eucryptite filler and the polymer derived ceramic matrix. Changes in the phase composition and changes of the unit cell parameters of β-eucryptite because of the formation of solid-solutions with silica originating from the SiO2 constituent of the polymer derived ceramic matrix were observed by Rietveld refinement. Tapes resulting from this process possess a sufficient mechanical stability and their coefficient of thermal expansion can be adjusted from slightly positive to moderate negative values.

Computational Modeling on the Influence of the Schmidt Number on Second Phase Impurities SiC, Si2N2O and Si3N4 in Grown mc-Silicon for PV Applications

The influence of the Schmidt number on the incorporation of SiC, Si2N2O and Si3N4 precipitate formation during directional solidification of mc-silicon was investigated. SiC, Si2N2O and Si3N4 particles that precipitate in multi-crystalline silicon for PV application have detrimental effects on the wafer sawing process and solar cell performance. Time-dependent numerical modelling of the mass transport phenomena has been used with a diffusion model. There is still no study on the Schmidt number during the mc-silicon growth process. So, the numerical study has been investigated on the formation of second phase inclusions in mc-silicon for various Schmidt numbers. It may be used to control the precipitate of SiC, Si2N2O and Si3N4 in a mc-silicon ingot. In this paper, the second phase inclusions that precipitate in the mc-silicon ingot have been simulated and analyzed for three different Schmidt numbers Sc = 1, Sc = 10 and Sc = 100. From the obtained results, Schmidt number Sc = 1 is found to grow better quality mc-silicon crystals.

Oxidation resistance of ZrB2 and ZrB2-SiC ultrafine powders synthesized by a combined sol-gel and boro/carbothermal reduction method

ZrB2 and ZrB2-SiC powders were prepared by a combined sol-gel and boro/carbothermal reduction method, and their oxidation kinetics was studied by using a non-isothermal thermogravimetric technique. The results showed that the Mample power law (n=1) was the most probable mechanism function, and the incorporation of SiC into ZrB2 greatly enhance the latter's oxidation resistance. The oxidation activation energy values of phase pure ZrB2 and ZrB2-SiC powders were respectively 249 and 308kJ/mol.

Influence of Cold Working on Mechanical Properties of Al-SiC Composites

The main objective of this research was a study the simultaneous influence of cold working and particle reinforcement on mechanical properties of Al. The model composites were fabricated by cold pressing RAl1 aluminium and 5% and 10% SiC powders and hot extrusion with ratio 3.8 in isothermal conditions at 480°C with 90° die angle to 18 mm diameter. Some specimens were then cold drawn with linear velocity 1 m/min to 16% area reduction, and one specimen in 3 passes to 51% reduction in area. Mechanical properties of the near fully dense composites were determined by axial compression, bend tests and hardness measurement and their microstructures examined, showing near homogenous distribution of SiC particles in the aluminium matrix. The increase in Young’s modulus was from 67 to 74 GPa and to 82 GPa for 5% and 10% reinforcement, respectively. Drawing increased average yield strength from 70 to 100 MPa for Al, and from 74 to 110 MPa and from 80 to 115 MPa, for 5 and 10% reinforcement, respectively. The results indicate that there is a significant increase in E, in accord with the law of mixtures, through incorporation of SiC and a synergistic effect of SiC and plastic deformation during drawing on strength. An attempt is made to identify the various contributions to overall strengthening of Al by considering also Al-8.8Cu-6.3%Si-0.7Mg alloy. It appears that alloying and age-hardening have the greatest effect, but that contributions from hot, warm and cold working are not insignificant. As powder metallurgy processing is an important fabrication method, their incorporation into the processing schedule merits consideration.