Nano SiC Research Articles

Simultaneous enhancement of thermoelectric and mechanical performance for SnTe by nano SiC compositing

SiC is firstly introduced into SnTe. The created lattice mismatch and interfaces via hand milling are responsible for the enhanced zT, which is comparable with doped samples. Besides, the hardness of samples is got improved with SiC compositing.

Assessment of the influence of additives in concrete by the Raman spectroscopy method

The effect of nano SiC additives with a particle size less than 50 nm, carbon black with a specific surface of about 80 m2/g, SiO2 and Al2O3 zol, AlCl3, FeCl3 solutions on the composition of silicon-oxygen anions in the pure C-S-H phase and hydrated cement was studied. The mixture was pressed at a specific pressure of 100 MPa and tested for compressive strength after 1, 7 and 28 days of normal aging. The Raman spectroscopy method was used to determine the composition of silicon-oxygen anions (SOA) in the C-S-H phase of cement and compared it with the strength of the stone, as well as with the SOA composition in the pure C-S-H phase. It was found that the initial powder of the C-S-H phase mainly contains isolated Q0 and terminal Q1 tetrahedra [SiO4]. Pressing the powder at 100 MPa leads to the advanced formation of chains of cross-linking Q2 and Q3 tetrahedra. The addition of silica to C-S-H promotes maximum chain formation from Q2. The Raman spectrum of C-S-H with silica zol is identical to the spectrum of hydrated cement. Iron chloride prevents the formation of extended chains of silicon-oxygen tetrahedrons. Carbon-containing nano-additives significantly alter the spectrum of C-S-H calcium substructures.

Deformation behavior and microstructure evolution of AZ31B composites containing multiscale distribution during room temperature tensile

The tensile strength of the AZ31B alloy with multiscale distribution has been greatly improved when compared with conventional Mg alloys. Its properties have also been determined to be sensitive to the interaction between multiscale SiC and dislocations. This work studies how multiscale SiC affects this material’s properties, as well as how it modifies the deformation/fracture behavior of matrix, through transmission electron microscope (TEM) examination of the elongated samples. When the strain increases, it is easy to form stress concentration in the zone around micron SiC, thus causing the activation of dislocation. The presence of relatively more number of small sized (evenly distributed submicron or nano) SiC seen in the space left between micron SiC would actively pin the dislocation and act as dislocation movement obstacle, resulting in the increase of dislocation density around SiC. Moreover, the addition of micron or submicron SiC is responsible for the increase of deformation stability. Although the strain localization around micron SiC could promote the nucleation of cracks, the dispersed nano or submicron SiC could delay and suppress the crack propagation. Moreover, compared with micron SiC, the nano SiC/Mg interface exhibits stronger bonding, so that the crack propagation is delayed due to the addition of nano SiC, and the ductility of material with multiscale distribution is reserved.

Micro/nanoscale structural, mechanical and tribological characterization of ZA-27/SiC nanocomposites

The structural, mechanical and tribological properties of ZA-27/SiC nanocomposites were investigated at micro/nanoscale. The nanocomposites with different volume fractions of nano-sized SiC particles were produced using the compocasting technique. The microstructure of nanocomposites was characterized with formation of SiC nano agglomerates, which were relatively uniformly distributed. The increase in SiC content contributed to the uniformity of their distribution. Also, the phenomenon of particle segregation in the form of particle-rich clusters, as well as particle-porosity clusters, was identified. The density level of composites decreased with the increase of the SiC content. The porosity followed a reverse trend. The tendency for formation of local particle-porosity clusters was the highest in ZA-27/1% SiC nanocomposite, causing the highest level of porosity. Increasing percentage of SiC content was followed by the increase in micro/nanohardness of the composites. The results of micro/nanoscale tribotests revealed that the reinforcing with SiC nanoparticles significantly improved wear and friction behavior of ZA-27 matrix alloy. The rate of improvement increased with the increase of SiC nanoparticle content, load, and sliding speed. The highest degree of changes corresponded to the change of the SiC nanoparticle content from 0 to 1 wt%. The further decrease of wear with SiC content (from 1 to 5 wt%) was almost linear. The different tribological behavior of tested ZA-27 matrix and ZA-27/SiC nanocomposites was influenced by differences of intensity of adhesion resulted in transferred layers of matrix material onto worn surfaces of Al2O3 ball counterpart. The intensity of adhesion significantly decreased with the increase of SiC nanoparticle content.

Effect of SiC nano particles on grain stability of friction stir processed AA7075

Friction stir processing (FSP) is a new technique to produce fine-grained microstructure with enhanced microstructure characteristics and mechanical properties compared to the base metal (BM). However, microstructures are not stable under elevated temperature. The microstructure of the friction stir processed (FSPed) metallic substrate can be improved by reinforcing the matrix with secondary phase particles. With this motivation, aluminium alloy plate of typically AA7075-T651 is reinforced with nano-particles of silicon carbide (SiCNP) and the composites were processed by FSP at the tool-rotation speed (TRS) of 1000 rpm and the tool-traverse speed (TTS) of 25 mm/min with six passes. The grain stability of the composite was studied by heat-treating to temperatures range 450 °C–500 °C for various durations range 1 h 30 min to 4 h 30 min. Micro and macrostructure of heat-treated samples are characterized using an scanning electron microscopy (SEM) and optical microscope (OM). Results showed that even after 4 h 30 min of samples subjected to heat treatment, the grains structures of the FSPed composites were stable at 450 °C. Further, for higher temperatures, i.e. 475 °C and 500 °C, composite grain structures at the stir zone (SZ) were stable up to 3 h. In comparison, abnormal grain growth (AGG) was observed in the six-pass FSPed aluminium alloy plate of AA7075-T651 without addition of SiCNP and heat-treated for 450 °C for 1 h 30 min. Thus, these experimental investigations indicate that grain boundary pinning by SiCNP has significantly increased the stability of the grains under elevated temperature and results in grain refinement with average grain size range 1.5–2 µm at the SZ of the FSPed composites.

Effect of ball milling and metal filler alloy on microstructural bonding of Al2O3-SiC nano ceramic composite

The ceramic composite (Al2O3 + 5 vol% nano SiC + 5 vol% Ni) was prepared with powder processing followed by microwave hybrid sintering in a conventional microwave oven (2.45 GHz, 900 W) at 1600 °C. Post sintering the relative densification, hardness and microstructure of the ball milled and the unmilled sample were examined and compared. Also the effect of ball milling and metal filler (Nickel) on microstructural bonding of alumina/SiC nano ceramic composite has been studied. Ball milled sintered composite achieved 93% relative densification and has higher indentation resistance as compared to unmilled sintered composite.

First-principle study of electronic structure and optical properties of SiC nano films

The structure, electronic and optical properties of 3C–SiC nano films were calculated according to first principles based on density functional theory. It is manifested that the nano films were structurally stable when the number of layers was increased to 12. Compared with bulk counterparts, nano films displayed narrower band gaps, and their Fermi energy levels were brought into the conduction band. The ε2(ω) of dielectric function, extinction coefficient, and absorption coefficient of the nano films were greater than that of the bulk in the ultraviolet range. With the layer numbers decreased, the values increased in the range. The results provide a guideline for 3C–SiC nano films to work for UV detectors.

Regulation of interface between carbon nanotubes-aluminum and its strengthening effect in CNTs reinforced aluminum matrix nanocomposites

Carbon nanotubes (CNTs) are popular as the chosen reinforcement to achieve excellent mechanical and functional performance in aluminum matrix nanocomposites (AMNCs). However, the key bottleneck problems restrict the strengthening effect using CNTs in AMNCs due to the dispersion homogeneity of CNTs, the distinct differences in physical properties, poor wettability and interface bonding between CNTs and aluminum matrix. This study aims to address these key issues by introducing a continuous SiC nano layer on CNTs surface synthesized from carbon-silicon reaction, acting as a compatibility transition layer prior to mixing with aluminum powders. The results clearly show that the SiC cladding layer provides a good wettability and strong interfacial bonding between CNTs and aluminum matrix, and the interfacial reaction between CNTs and aluminum matrix could be effectively regulated. It is also conducive to reducing the mass density difference and specific surface energy, improving the dispersion of CNTs in matrix. Those factors make a strong contribution to the strengthening effect of CNTs enforcement by achieving high load transfer efficiency. The AMNCs reinforced by this new CNTs/SiC composite powder show clear improvement of mechanical performance without compromising in ductility and electrical conductivity, as compared to AMNCs reinforced by only CNTs or SiC.

Evaluation of Mechanical Behavior of Hybrid Natural Fiber Reinforced Nano Sic Particles Composite using Hybrid Taguchi-Cocoso Method

For this present research investigation, hybrid natural fiber reinforced Nano SiC particles composite was fabricated and their mechanical properties has been studied. Experiments have been planned as per Taguchi’s Method. After preparing the composite material by hand layup technique and then the mechanical characterizations are performed. Multi-response optimization has been carried out by employment of a recently developed method for multi-criteria decision making (MCDM), i.e. combined compromise solution (CoCoSo) method. For defining the relative significance of measured norms, pairwise comparison matrix was used. Optimal results have been verified through confirmatory experiments. Based on the experimental observations ultimate tensile strength (UTS), density and flexural strength, ANOVA result indicated that density has highest impact for a better mechanical behaviour. This can be useful in different field of application for fabrication of different structures, parts etc.

Preparation and characterization of pure SiC ceramics by high temperature physical vapor transport induced by seeding with nano SiC particles

High temperature physical vapor transport (HTPVT) was employed to grow polycrystalline SiC ceramics with high density and purity, induced by nano SiC particles as seeds. The obtained SiC ceramics were identified as 6H-SiC with a mainly preferred orientation along the (0 0 0 6) plane, and an obvious refinement of grain size was demonstrated for the SiC seeds. Mean grain sizes of the obtained SiC ceramics were 112 μm and 314 μm, by using the SiC seeds with the mean particle size of 50 nm and 500 nm, respectively, which were obviously smaller than that of the seed-free sample (960 μm). The samples obtained with the seeds also demonstrated enhanced flexural strength and hardness, attributing to the reduced mean grain size. Furthermore, SiC ceramics without seeds via HTPVT exhibited a high thermal conductivity of 242 W·(m·K)−1 at room temperature due to the highly preferred orientation. While the degree of preferred orientation of seed-induced samples was lower, the thermal conductivity of SiC ceramics induced by seeding still maintained at least 200 W·(m·K)−1 at room temperature, this level was much higher than most other methods. Therefore, seed-induced method appears to be an effective way to control structures and behavior of SiC ceramics through HTPVT.

The Effect of Variation of Nano SiC Reinforcement Particle Addition to Mechanical Properties of Mg/Nano SiC Composite by Stir Casting Method

Composites are advanced material which is being developed that contains of two materials or more in order to improve the mechanical properties. Magnesium composite is a suitable material beside aluminium and its alloy to be applicated as vehicle body structure due to its lightweight and its low density. Thus, the vehicle body structure with lightweight and good mechanical properties can be achieved. In this research, magnesium composite is fabricated by mixing magnesium as composite matrix and nano SiC as reinforcement particle with the variation of the volume fraction 0.05 %vf, 0.10 %vf, 0.15 %vf, 0.20 %vf, and 0.25 %vf with stir casting as fabrication methods. To characterize the composite product, several testing were done, which were chemical composition characterization, metallographic observation, SEM-EDS characterization, XRD characterization, hardness testing, wear testing, and impact testing. The result of this research shows that with nano SiC addition as reinforcement particle will increase mechanical properties of magnesium composite. The best mechanical properties of magnesium composite is shown by the addition of 0.15 %vf nano SiC. The result shows the brinnel hardness number of this composition is 39 HB and 0.0052 mm3/m wear rate. Mechanical properties of magnesium composite are increased due to several strengthening mechanism such as grain size reduction and Orowan strengthening mechanism.

Erosion Wear Behavior of SiC Nano Powder Filled Flax and Sisal Fabric Hybrid Composites with Taguchi Experimental Design

This work is carried out to find out the erosion wear characteristics of unfilled and also SiC nanopowder filled flax and sisal fabric hybrid composites (FSHC). Effect of different parameters such as filler content, impingement angle and erodent size on the erosion wear behavior of hybrid composite has been studied using Taguchi method. Significant control factors altering the erosion rate have been evaluated through outstanding execution ANOVA. The experimental outcomes are recognized to be in acceptable accord with the assumptive values. This study indicates that erosion wear resistance increases as SiC nanopowder increases in FSHC

Evaluation via powder metallurgy of nano-reinforced iron powders developed for selective laser melting applications

In this work, a gas atomised stainless steel AISI 316L powder was used as metal matrix and SiC was employed as a nano reinforcement. The powders were experimentally characterised to determine the effect of the morphology, size, and levels of reinforcement on the powder flowability. The powder was developed via the powder metallurgy route and the effect of material, process conditions and various levels of reinforcement were investigated through the microhardness of the sintered samples. Sintered samples produced from the 316L + SiC + PVA powder mixes presented improved hardness. Analysis of the Energy Dispersive X-ray measurements detected high intensity levels of carbon and silicon on the surface of the reinforced 316L particles. In terms of measured powder rheology, the 6 wt% SiC coated 316L provided the highest flowability of the prepared SiC coated 316L powders and a much higher flowability than the as received 316L powder. All prepared SiC coated 316L powders showed good flowability and highly repeatable powder rheology. The high degree of flowability was attributed to the particle spherical morphology, the narrow range of particle size distribution and also the coating of nano SiC particles on the 316L particles which were found to act in this case as a solid lubricant. A successful homogeneous and uniform reinforcement of SiC onto the surface particles was resultant from the established mixing technique. While the nano-SiC improved the powder fluidity, the obtained improvement in hardness was also due to the nano-SiC dissolution and resultant precipitates formed during the thermal treatment.

Effect of nano and micro SiC particles on the microstructure and fracture toughness of ZrB2-SiC nanocomposite produced by SPS method

In this research, effect of SiC particles size on the microstructure, densification and fracture toughness of ZrB2-SiC composite prepared by spark plasma sintering (SPS) method was evaluated. For this purpose, ZrB2-30vol% SiC composites were consolidated by SPS method, using SiC powders with different initial particle sizes (45 nm, 80 nm and 25 μm). Scanning Electron Microscopy (SEM) was used to study the microstructural evolutions. Relative density and open porosity were measured by Archimedes .In order to evaluate the fracture toughness and toughening mechanisms, the SENB method and the crack growth resulted from the Vickers indentation were used respectively. The results showed that by reducing the size of the initial SiC particles from the micrometer scale to the nanometer scale, the size of the ZrB2 matrix grains also decreased, which led to increase the relative density. Also, applying nano-SiC particles compared to micrometer, led to considerable increase in the fracture toughness. Microscopic examination of the crack propagation path from Vickers indentation effect showed that crack deviation and crack branching were activated as the most important toughening mechanisms in ZrB2-SiC composites.

Development and characterization of nanoparticle metal matrix composites: (Al 2024-SiC np)

Composite materials get an importance in value as an advance materials such as automotive, aerospace, aircraft, defense, medical, marine, sports, recreation and various engineering applications due to their high strength-to- weight ratio, good cast ability and better tribological properties. Al-base 2024 alloy reinforced with SiC micron and nano particles were developed using stir casting technique due to low cast, ease in fabrication, recyclability and isotropic characteristics. The development of Aluminum metal matrix nano composites (AMMNCs) is most considered material for high temperature applications because of their excellent mechanical properties, increase performance and weight saving for more reduction of fuel consumption. The results indicate that Al–SiC composite has improved physical and mechanical properties such as tensile strength, charpy impact strength, brinell hardness, density and porosity percentage. Samples with micron particles and nano particles were developed to compare the properties of both. Microstructures of the samples were studied by means of x-ray Diffraction and Scanning Electron Microscopy. The elemental composition was also analyzed through Energy Dispersive Spectroscopy. It was found that composites of Al–SiC have better and improved physical properties in nano dimensions.

Multiple Performance Optimization in Wear Characteristics of Mg-SiC Nanocomposites Using Grey-Fuzzy Algorithm

The present investigation attempts to evaluate the effect of the SiC nano particles on the wear characteristics of Mg matrix nano composites. The wear tests on Mg matrix composites reinforced with SiC nanoparticles were carried out using the pin-on-disc tribometer under dry sliding conditions at various applied loads, sliding distance and speeds. The experiments were planned by adopting Taguchi L9 orthogonal array. The wear performances such as Specific wear rate and coefficient of friction were optimized by grey based fuzzy algorithm. The morphologies of the worn surfaces were observed by scanning electron microscopy (SEM) and important wear mechanisms were identified. The average compositions of the transfer layer formed at the worn surfaces were ascertained by EDX. Improved wear performances were exhibited by nano SiC reinforced composites at elevated conditions.

The Enhancement of Wear Properties of Compo-Cast A356 Composites Reinforced with SiC nano Particulates

Metal matrix composites producer of a new generation of metal materials in which ceramic reinforcement has been added to the metal field, which has enhanced various properties such as special strength, wear resistance, corrosion resistance and elastic modulus. Aluminum composites reinforced with ceramic particles due to excellent mechanical, physical and tribological properties are among composites with extensive application. Among these, Al–SiC composites have been considered important in certain industries such as aerospace and automotive for their desirable properties such as strength, wear resistance, toughness, and suitable hardness. In this study, the effect of casting methods on the wearing properties of Al–SiC composites has been investigated. Also, the effect of applied shear force on the hardness and porosity of these composites has been thoroughly investigated. According to the results of the wear test, by increasing the applied current rate, wear resistance in the samples improved, the reason of which is the direct dependence of the wear strength of the samples on hardness, and the porosity in the composites.

SiC composite based selective electromagnetic propagation for GHz application

Nano SiC composite has been used intensively in this study to understand its transparency to electromagnetic waves. Different materials have been used as additive fillers in nanoscales to normalize the transmission ability of SiC in a way allows more transparency of electromagnetic. ZnO, Ni, Si, Fe2O3, and Fe3O4 were implemented as additive fillers. Cold pressing method was adopted to fabricate the green samples. A set of samples contained varied filler ranging of 50, 30, 10 percent particle reinforcement. The complex permittivity and permeability were measured using network analyzer by using transmission line theory. The results revealed that the increase in particle filler, especially ZnO increase the transmission of EM. Fe3O4 shows a maximum reflection performance due to the high amount of iron particles. The transmission ability of SiC was controlled by changing the weight fraction of fillers, causing the transparency of SiC to be increased to a maximum value.

Influence of SiC ceramic reinforcement size in establishing wear mechanisms and wear maps of ultrafine grained AA6063 composites

Abstract This paper described the influence of varying sizes of SiC ceramic reinforcement (coarse (12 μm), fine (1 μm) and nano (45 nm)) in establishing the wear mechanisms and the wear mechanism maps of ultrafine grained (UFG) AA6063/4 wt%SiC composites. The UFG composites were developed by a hybrid manufacturing route of stir casting and cryorolling. The pin-on-disc machine under normal loads of 10–50 N and sliding speeds of 0.5–2 m/s was used to investigate wear behavior. The synergetic effect of cryorolling and varying ceramic reinforcement size has resulted in microstructural modification and has reducing effect on specific wear rate. Microstructural characterization revealed that, cryorolling has accumulated high dislocation density and arrested recovery and recrystallization at liquid nitrogen temperature. Frictional heat generated at wear surface with increase in sliding speed and load has activated the dynamic recovery, recrystallization and precipitation which further increased the hardness and reduced the specific wear rate. The wear mechanisms were established for UFG materials. The wear mechanism maps were constructed and correlated with the microstructures of worn surfaces of UFG materials to identify the dominant wear mechanism.

Microstructure and mechanical properties of copper surface composite layers reinforced by nano and microscale SiC particles via friction stir processing

Although the high thermal and electrical conductivity properties of copper (Cu) have resulted in its widespread industrial applications, its weak surface properties usually caused some limitations. In this study, the effect of graphite (Gr) and silicon carbide nanoparticles (SiCNPs) on the surface properties of copper metal-matrix composites (CMMCs) was investigated. Friction stir processing (FSP) was applied to the preparation of the Cu/SiCNPs, Cu/Gr and Cu/SiCNPs+Gr CMMCs. Then the microstructures, hardness and wear properties of the prepared surface composites were investigated and compared with samples in the absence of reinforcement particles. Evaluation of the microstructure of composites showed an extensive reduction in grain size compared to FSPed metal (e.g., 70 µm in FSPed copper to an average of 300 nm in the Cu/SiCNPs). The results also showed that the hardness of Cu/SiCNPs composites is 100 HV, which is much higher than that of FSPed copper (with the hardness of about 60 HV). The wear test results showed that the presence of SiCNPs alone and with SiCNPs+Gr particles increase the coefficient of friction, relative to FSPed copper, while the presence of Gr particles alone results in a significant reduction of this parameter.