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In the present study, the unique three-dimensional graphene coated nickel (Ni/C) foam reinforced silicon carbide (Ni/C@SiC) composites were first obtained via the precursor impregnation and pyrolysis (PIP) processes. The microstructure images indicated that the SiC fillers were successfully prepared in the skeleton pores of the Ni/C foam. The influence of the PIP cycles on the microwave absorption performances was researched, and the results indicated that after the primary PIP process, Ni/C@SiC–I possessed the optimal microwave absorbing performance with a minimum reflection loss(RL) of −25.87 dB at 5.28 GHz and 5.00 mm. Besides, the RL values could be below −10.00 dB from 5.88 GHz to 7.74 GHz when the corresponding matching thickness was 3.85 mm. However, the microwave absorption properties of Ni/C@SiC-II and Ni/C@SiC-III were tremendously degraded as the PIP times increased. At last, the electromagnetic parameter, dielectric loss, attenuation constant as well as impedance matching coefficient were further investigated to analyze the absorbing mechanism, which opened a new path for the certain scientific evaluation of the absorbing materials and had extremely important to the defence technology.

This research aims to examine HAMC’s tribology’s performance-[Hybrid Aluminium metal matrix composites] reinforced with Silicon carbide, Nickel & Graphite at different temperature conditions for thermal applications. This is highly significant for applications with high-temperature. The HAMCs were developed by stir casting method by reinforcing particles like SiC (5% & 10%) and Ni.-Gr. (2% fixed) into LM26 aluminium alloy. The wear rate and friction coefficient of the material is analyzed through pin-on-disc apparatus. The parameter impact on applied load, wt%, sliding distance, and the temperature is analyzed using an L9 orthogonal array. COF and wear loss of the proposed HAMC is determined using the ANOVA method. The Tribological property of HAMC is mainly influenced by applied load and temperature. The varying hybrid % controls the COF and wear loss. The SEM analysis is used to assist the performance of the worn surface.

Machines are integral part of industrial concerns and establishments. Tools are the backbone of machinery and vary according to the application they are being put used to as well as the end product required. Tool wear, on a comparative scale, is more predominant factor in cutting applications. This may be attributed towards a number of factors such as the high temperature arising at the cutting junction, frictional forces being generated; feed rate etc. Conventional methods utilize various alternatives such as lubricants in the form of grease, oil etc. and specially designed cooling fluids. In spite of their beneficial functions, they tend to provide health hazard due to consequent environmental pollution. By using minimum quantity lubrication system, it saves 50% of coolant which done for machining and also reduce environmental problems. In silicon carbide nano additive gives least metal removal rate compared with copper oxide and titanium oxide.

This paper deals about the optimization and modelling of Wire cut Electric Discharge Machining factors such as pulse OFF-Time (Toff), gap voltage (Vg) and pulse ON-Time (Ton) during machining nano- silicon carbide (nSiC) and nano-zirconium oxide/zirconia (nZrO2) reinforced in Al6061 aluminium alloy matrix. Nanomaterial is synthesis in the planetary high energy ball milling and the hybrid aluminium metal matrix composite (HAMMC) was fabricated by using the stir casting technique. For performing machinability studies on the cast composite. To design the experiments, Response Surface Methodology (RSM) based central composite design (CCD) with face-centred approach is implemented. To optimize input conditions, kerf width and surface roughness were analysed. To determine the suitability of the developed model, Analysis of Variance (ANOVA) is applied and to model the process factors regression analysis is carried out. It is observed from the results that, kerf width decreases when Toff increases and increases with increase in Ton and Vg. A decreasing trend of surface roughness is observed with increasing trend of Vg and surface roughness increase with increase in Ton increases.

International audience; Coatings with composition close to Ti3SiC2 were obtained on SiC substrates from Ti and Si powders with the molten NaCl method. In this work, the growth of coatings by reaction in the salt between monolithic SiC substrates and titanium powder is obtained between 1000 and 1200°C. At 1000°C, a coating of 8 µm thickness is formed in 10 hours whereas a thin coating of 0.5 µm has been grown in 2 hours. A lack in silicon was first found in the coatings prepared at 1100 and 1200°C. For these temperatures, the addition of silicon powder in the melt had a favorable effect on the final composition, which is found very close to the composition of Ti3SiC2. The reaction mechanism implies the formation of TiCx layers in direct contact with the SiC substrate and the presence of more or less important quantities of Ti3SiC2 and Ti5Si3Cx in the upper layers.; Des revêtements de composition proche de Ti3SiC2 ont été obtenus sur des substrats SiC à partir de poudres Ti et Si par la méthode du NaCl fondu. Dans ce travail, la croissance de revêtements par réaction dans le sel entre des substrats monolithiques SiC et de la poudre de titane est obtenue entre 1000 et 1200°C. A 1000°C, un revêtement de 8 µm d'épaisseur est formé en 10 heures alors qu'un revêtement fin de 0,5 µm a été développé en 2 heures. Un manque de silicium a d'abord été trouvé dans les revêtements préparés à 1100 et 1200°C. Pour ces températures, l'ajout de poudre de silicium dans le bain a un effet favorable sur la composition finale qui se retrouve très proche de la composition de Ti3SiC2. Le mécanisme réactionnel implique la formation de couches de TiCx en contact direct avec le substrat SiC et la présence de quantités plus ou moins importantes de Ti3SiC2 et Ti5Si3Cx dans les couches supérieures.

A modified technique for the growth of silicon carbide from silicon by the method of self-consistent substitution of atoms is proposed, which makes it possible to increase the achievable thickness of the formed silicon carbide layer by about an order of magnitude. The technique includes an additional step before the growth process: the surface of the silicon substrate is being saturated with vacancies by annealing in vacuum at T = 1350 ℃ for ~ 30 min. This leads to a change in the mechanism of mass transfer from the interstitial to the vacancy one when silicon atoms are being substituted by carbon atoms. As a result, not only the thickness of the silicon carbide layer increases, but also the separation of silicon carbide from the silicon substrate occurs if the thickness of the SiC layer surpasses 400 nm.

A silicon carbide (SiC) protective coating has been developed for dental ceramics, but whether the coated ceramics can match the classical VITA shades is unclear.The purpose of this observational in vitro study was to evaluate the color adaptability of SiC-coated dental ceramics by testing the hypotheses that SiC-coated disks can be fabricated to match standard tooth shades and have a perceptible color match rate of at least 50% for disks with a color difference (ΔE)2.0. The effects of ΔE, shade hue, shade value, observer sex, years of experience, profession, and shade guide orientation on color perception were studied.SiC-coated disks were fabricated to color match (ΔEA significant difference in color match rate was found between disks with ΔE2.0 (63.9%) and ΔE≥2.0 (41.7%) (P.001). Arranging shade by value (72.2%) instead of hue (67.2%) produced better color matching (P.001). Sex (P=.430), profession (P=.708), and years of experience (P=.902) had no significant influence on color matching.SiC-coated disks were successfully fabricated to match all VITA classical shades, and clinical visual color matching results confirmed that ΔE was a useful metric in optimizing color matching for the SiC-coated dental ceramics.

Silicon Carbide (SiC) MOSFET devices have smaller chip size and higher current density than Si counterparts, which results in the limited short-circuit capability of SiC power modules. The presently used protection circuit is actually conventional desaturation protection method, which is very suitable for IGBT modules. But this conventional protection circuit has relatively slow response, and cannot be directly used in SiC modules due to its higher di/dt and weaker ruggedness compared to IGBT modules. So we propose an improved desaturation protection method. We first analyse the short-circuit process to obtain the short circuit characteristics of SiC MOSFET. Then, we give the principle of the improved desaturation protection method, and present the comparison between the conventional protection circuit and the improved one. At last, short-circuit protection tests under HSF and FUL faults have been conducted to verify the improved desaturation protection circuit. The experimental results show that the improved desaturation protection circuit has a faster response than the traditional one, and can make SiC modules work reliably.

Titanium silicon carbide (Ti3SiC2) film was synthesized by molten salt synthesis route of titanium and silicon powder based on polymer-derived SiC fibre substrate. The pre-deposited pyrolytic carbon (PyC) coating on the fibre was utilized as the template and a reactant for Ti3SiC2 film. The morphology, microstructure and composition of the film product were characterized. Two Ti3SiC2 layers form the whole film, where the Ti3SiC2 grains have different features. The synthesis mechanism has been discussed from the thickness of PyC and the batching ratio of mixed powder respectively. Finally, the obtained Ti3SiC2 film was utilized as interphase to prepare the SiC fibre reinforced SiC matrix composites (SiCf/Ti3SiC2/SiC composites). The flexural strength (σF) and fracture toughness (KIC) of the SiCf/Ti3SiC2/SiC composite is 460 ± 20 MPa and 16.8 ± 2.4 MPa∙m1/2 respectively.

Zirconium diboride (ZrB2) and silicon carbide (SiC) composites have long been of interest since it was observed that ZrB2 improved the thermal shock resistance of SiC. However, processing of these materials can be difficult due to high and different sintering temperatures and differences in the thermodynamic stability of each material. ZrB2–SiC composites have been processed in a variety of ways including hot-pressing, spark-plasma sintering, reactive melt infiltration, pack cementation, chemical vapor deposition, chemical vapor infiltration, stereolithography, direct ink writing, selective laser sintering, electron beam melting, and binder jet additive manufacturing. Each manufacturing method has its own pros and cons. This review serves to summarize more than 60 years of research and provide a coherent resource for the variety of methods and advancements in development of ZrB2–SiC composites.

A systematic and extensible framework for quantification of structural hierarchy is indispensable to understand the structure–property correlation of SiC ceramics. Microstructural hierarchy descriptor (μSHD) is constructed and used to quantify experimental microstructures reported in the literature. Despite a variation nature of microstructures and the scatterness in measured properties, μSHD–property correlations have been identified. The μSHD curves with less hierarchical levels suggest a high strength, while more hierarchical levels are related to a high toughness. The μSHD curve exhibiting a homogeneous distribution across all the scales and one exhibiting a gradual decrease from the smaller to larger scales can both stand for a high thermal conductivity. A quick drop from the smaller to larger scales on the μSHD curve is a characteristic of a high electrical resistivity, and a reverse trend, showing a gradual increase from smaller to larger scales and maintaining larger μSHDs at larger scales, characterizes a low resistivity.

In pursuing high precision and high-quality surface of silicon carbide (SiC) substrates for electronic applications, however, the processing efficiency on Si-face has long been a difficult challenge compared to that of the C-face. Conventional polishing slurries are aqueous-based due to its unparalleled compatibility with most of chemical reagents, and have been widely studied and well understood. The chemical reactivity of all added accelerating agents in aqueous polishing systems is constrained by the prevalent presence of water as a solvent. On the other hand, non-aqueous polishing systems have not been well explored. In this report, reactive non-aqueous organic systems containing polar hydroxyl groups are evaluated as a high efficiency processing vehicle for Si-face polishing of SiC on fixed abrasive pads (FAPs). The surface quality of SiC is surprisingly improved while the polishing efficiency is accelerated on a diamond FAP in presence of methanol compared to those using water, and are further improved when organic acids are introduced to the reactive non-aqueous fluids. Contact angle measurement and X-ray photoelectron spectroscopy (XPS) analysis on the polished SiC surface are completed to assist us to shed light on the removal behavior and to explore and elucidate the removal mechanism of non-aqueous system fluids on FAPs. The initial positive results from this reactive non-aqueous polishing system serves our community as a promising approach for the ultra-precision polishing on other hard-to-process semiconductor and ceramic materials.

With increasing ballistic threat levels, there is ever more demand on developing ceramic armor designs with improved performance. This paper presents finite element simulations that investigate the performance of silicon carbide ceramic with steel 4340 backing material and titanium alloy, graphite as buffer layers when subjected to normal and oblique impacts by a tungsten alloy long rod projectile (LRP). Depth of penetration from experimental measurements is compared with simulations to confirm the validity of constitutive, failure model parameters. Titanium alloy cover plate and graphite interface weak layer laterally spread the impact shock away from the SiC tile and reduces the amplification of the stress accumulation at the front surface of the SiC tile. The dwelling time increases before it penetrates into ceramic armor. Further, using AUTODYN® numerical simulations detailed parametric study is carried out to identify the minimum areal density armor for a given ballistic limit velocity. The equivalent protection factor for the bi-layer armor is a simple function of the cosine of the angle of impact.

Silicon carbide fiber-reinforced silicon carbide ceramic matrix composite (SiCf/SiC) is promising for manufacturing aero-engines because of its high-temperature resistance and lightweight. However, since SiCf/SiC is hard and brittle, the machining of SiCf/SiC has been suffering from uncontrolled machining-induced damages, such as edge chipping, cracks, fiber breakage. This paper studies the edge chipping characteristics of SiCf/SiC in brittle removal mode in single grain grinding. It is found that the edge chipping in grinding SiCf/SiC is complicated. The edge chipping in grinding the SiC matrix is dependent on the pre-existed defects rather than grinding parameters. While the edge chipping in grinding SiC fibers is dependent on both fiber orientation and grinding speed. The edge chipping in the grinding perpendicular to the fiber orientation is larger than that in the grinding along with the fiber orientation. It decreases with increasing grinding speed. Increasing grinding speed from 20 m/s to 50 m/s and 90 m/s, the width of the edge chipping area decreases by 30% and 60% respectively. While in the grinding along with the fiber orientation, edge chipping is minor and insensitive to grinding speed. Therefore, this study represents that increasing grinding speed would not enlarge the edge chipping but greatly increase the material removal rate, which is important for the surface finish and damage control of the machining of SiCf/SiC.

The high-temperature compression creep of additive-free β/α silicon carbide ceramics fabricated by rapid hot pressing (RHP) was investigated. The creep tests were accomplished in vacuum at temperature range 1500 °C–1750 °C and compressive loads of 200 MPa to 400 MPa. Under investigated condition the RHP ceramics possessed the lowest creep rate reported in the literature. The observed strain rates changed from 2.5 × 10−9 s−1 at 1500 °C and a lowest load of 275 MPa to 1.05 × 10−7 s−1 at 1750 °C and a highest load of 400 MPa. The average creep activation energy and the stress exponent remain essentially constant along the whole range of investigated parameters and were 315 ± 20 kJ∙mol−1, and 2.22 ± 0.17, respectively. The suggested creep mechanism involves GB sliding accommodated by GB diffusion and β−α SiC phase transformation.

We studied the morphological nature of various thin films such as silicon carbide (SiC), diamond (C), germanium (Ge), and gallium nitride (GaN) on silicon substrate Si(100) using the pulsed laser deposition (PLD) method and Monte Carlo simulation. We, for the first time, systematically employed the visibility algorithm graph to meticulously study the morphological features of various PLD grown thin films. These thin-film morphologies are investigated using random distribution, Gaussian distribution, patterned heights, etc. The nature of the interfacial height of individual surfaces is examined by a horizontal visibility graph (HVG). It demonstrates that the continuous interfacial height of the silicon carbide, diamond, germanium, and gallium nitride films are attributed to random distribution and Gaussian distribution in thin films. However, discrete peaks are obtained in the brush and step-like morphology of germanium thin films. Further, we have experimentally verified the morphological nature of simulated silicon carbide, diamond, germanium, and gallium nitride thin films were grown on Si(100) substrate by pulsed laser deposition (PLD) at elevated temperature. Various characterization techniques have been used to study the morphological, and electrical properties which confirmed the different nature of the deposited films on the Silicon substrate. Decent hysteresis behavior has been confirmed by current-voltage (IV) measurement in all the four deposited films. The highest current has been measured for GaN at ∼60 nA and the lowest current in SiC at ∼30 nA level which is quite low comparing with the expected signal level (μA). The HVG technique is suitable to understand surface features of thin films which are substantially advantageous for the energy devices, detectors, optoelectronic devices operating at high temperatures.

In this study, silicon carbide (SiC) composites reinforced with pitch-based carbon fibers and composed of heat transfer channels were fabricated by combining chemical vapor infiltration and reactive melting infiltration method. It was observed that the internal heat conduction skeleton of pitch-based carbon fibers was sequentially formed. The thermal conductivities from room temperature to 500 °C along through-thickness direction and in-plane direction were investigated. The results showed that Cpf/SiC composites with heat transfer channels possessed excellent thermal conductvity in two directions, and the thermal conductivity increased with increasing volume content of heat transfer channels. The thermal conductivity in through-thickness direction reached 38.89 W/(m·K), and that for in-plane direction reached 112.42 W/(m·K). Theoretical calculations were empolyed to study the temperature dependence of the Cpf/SiC composites. The variations in slope A′ and intercept B′ values of fitted curves were in good agreement with the experimental results. To verify the reliablilty of the theoretical model, the Cpf/SiC composites were heated at 1650 °C for 2 h and the thermal conductivity exhibited further improvement due to the formation of more perfect crystalline structure. Thermal conductivity through thickness direction improved to 43.49 W/(m·K), and that in in-plane direction improved to 142.49 W/(m·K), which could be identified by the theoretical model. Finally, the leading edge model was established by using ABAQUS finite element analysis software to evaluate the potential application of the composites. Owing to the outstanding thermal conductivity, the leading edge obtained by using Cpf/SiC composites in this study exhibited lower temperature gradient and a more uniform temperature distribution. Moreover, less thermal stress and displacement were generated during heating process.

In this study, Al2O3-SiCw-Si3N4-based ceramic tool materials were fabricated by spark plasma sintering technique. The impact of sintering temperature on mechanical properties and local microstructure was thoroughly investigated. Moreover, detailed comparison was performed between spark plasma sintering and early hot-pressing sintering methods. Evolution law and mechanism of high-temperature mechanical properties were also investigated. Composites with higher density and enhanced mechanical properties were obtained by spark plasma sintering at temperature of 1500 °C, which was 100 °C lower than hot-pressing temperature. The cross-interlocking structure of generated β-Sialon particles and silicon carbide (SiC) whiskers could effectively improve mechanical properties of material configuration. Moreover, Vickers hardness and fracture toughness of ceramic composites decreased by elevating temperature (20–1000 °C); however, following percentages at 1000 °C were still maintained with respect to values at room temperature, i.e., 67 and 51%. This effect is attributed to existence of Sialon phase, healing of partial cracks, as well as manifestation of whisker pullout process. As a result, decreased attenuation rate under high-temperature conditions of respective mechanical properties was observed. Our approach provides useful insights into potential fabrication of novel material configurations with relatively low thermal budget and enhanced mechanical performance.

In this work we evaluated the effect of adding Si as sintering additive into SiC for producing air-sintered hollow fiber membranes. According to crystallographic analyses, SiC and Si were converted to SiO2 after sintering at 1350 °C. The addition of 30 wt% of Si into SiC ceramic material promoted the binding of SiC particles and improved the membrane mechanical resistance to 42.25 ± 3.39 MPa after air sintering at 1350 °C. The produced asymmetric ceramic membrane presented a packed pore-network and micro-voids with pore sizes of 1.73 and 5.29 μm, respectively. The filtration of an oil/water emulsion enabled oil retention 98.75 ± 0.95 %. Cake formation was the main fouling occurrence and membrane regeneration with equivalent oil retention and similar steady sate flux was achieved after water cleaning under ultrasound irradiation. Thus, the use of Si as air-sintering aid was favorable for producing Si-bonded SiC hollow fiber membranes with suitable application for oil/water separation.

Direct reaction of precursors with the products of detonation remains an underexplored area in the ever-growing body of detonation synthesis literature. This study demonstrated the synthesis of silicon carbide during detonation by reaction of elemental silicon with carbon products formed from detonation of RDX/TNT mixtures. Continuum scale simulation of the detonation showed that energy transfer by the detonation wave was completed within 2–9 μs depending on location of measurement within the detonating explosive charge. The simulated environment in the detonation product flow beyond the Chapman-Jouguet condition where pressure approaches 27 GPa and temperatures reach 3300 K was thermodynamically suitable for cubic silicon carbide formation. Carbon and added elemental silicon in the detonation products remained chemically reactive up to 500 ns after the detonation wave passage, which indicated that the carbon-containing products of detonation could participate in silicon carbide synthesis provided sufficient carbon-silicon interaction. Controlled detonation of an RDX/TNT charge loaded with 3.2 wt% elemental silicon conducted in argon environment lead to formation of ∼3.1 wt% β-SiC in the condensed detonation products. Other condensed detonation products included primarily amorphous silica and carbon in addition to residual silicon. These results show that the energized detonation products of conventional high explosives can be used as precursors in detonation synthesis of ceramic nanomaterials.

Self-lubricating polyphenylene sulfide (PPS) composites were fabricated by constructing a segregated network structure using the co-deposition method. Both carboxyl-functionalized multi-walled carbon nanotubes (CNTs) and silicon carbide (SiC) were successfully coated on the surface of PPS powders with the aid of self-polymerization of dopamine (PDA) and co-polymerization between PDA and polyethyleneimine (PEI), thereby forming PPS@PDA-CNTs-SiC hierarchical reinforcing hybrids. Results showed that the thermal conductivity of PPS@PDA-CNTs-SiC (0.97 W/(m K)) is about 120% higher than that of PPS/CNTs/SiC. The friction coefficient (0.193) and specific wear rate (2.50 × 10−5 mm3/(N m)) of PPS@PDA-CNTs-SiC are 18.9% and 50% lower than those of PPS/CNTs/SiC, respectively. The enhanced thermal conductivity of PPS@PDA-CNTs-SiC contributes to rapid dissipation of frictional heat at the sliding interface which protects the polymer substrate from being destroyed or peeled, thereby improving the tribological performance. This work provides new insights into expanding the application of self-lubricating polymer composites in the fields where efficient heat dissipation is also a primary concern.

The machining of silicon carbide (SiC) ceramic matrix composites is a significant challenge because of the severe material damage that may occur during material removal, which might shorten the service life of the composite parts. In this study, the effects of different fibre orientations of two-dimensional woven carbon-fibre-reinforced silicon carbide matrix composites (2D-Cf/SiC) on the grinding force, surface roughness, and surface/subsurface micromorphology were investigated to clarify the material removal and breakage mechanism in ultrasonic-assisted grinding of ceramic matrix composites. The results show that the predominant material removal mode in ultrasonic-assisted grinding is brittle fracture. The forms of material breakage are matrix cracking, fibre fracture, fibre pull-out, interfacial debonding, and interfacial fracture. Compared with conventional grinding, the normal force, tangential force, and surface roughness in ultrasonic-assisted grinding decreased by approximately 20%, 18%, and 9%, respectively. The machining parameters significantly impacted the grinding force and surface roughness. The material removal modes varied for different fibre orientations. Ultrasonic-assisted grinding can effectively decrease the grinding force and improve the surface integrity. The findings of this study can be applied to predict the grinding force and surface integrity of 2D-Cf/SiC and contribute to the design and manufacturing of this type of material.

This paper deals with the comparison of Mechanical properties of aluminum alloy (LM 25) with boron carbide and aluminum alloy with silicon carbide metal matrix composite. The boron carbide of particle size 35 to 40 µm and silicon carbide of similar particle size were used as reinforcements. This addition gives excellent hardness and good impact strength. The fabrication was done by using stir casting., The samples are prepared and mechanical testing like tensile, hardness, and impact was done. It was found that aluminum alloy with boron carbide showed better tensile and impact strength whereas aluminum alloy with silicon carbide showed better hardness. The structure was characterized by using optical microscope.

Silicon carbide (SiC), a non-oxide ceramic with superior thermo-mechanical stability, chemical and radiation resistive properties, finds extensive utilization in optical instruments for terrestrial and space applications. However, its inherent porous texture (α-HCP) becomes a deterrent for high-performance optical telescopes, although several techniques of surface alterations over sintered or reaction-bonded SiC are available. In the present work, the physical vapour deposition (PVD) technique is adopted to deposit a thick (∼5 μm) Silicon dioxide (SiO2) clad layer on a sintered and optically polished SiC (SSiC) substrate. SiO2 clad layer coated SSiC (SDO-SSiC) substrate reduces the surface porosity of SSiC which is found to be suitable for optical mirror application. Finally, an Al based reflective and oxides protective coatings are deposited on SiO2 clad layer to achieve reflective behaviour. The surface figure of 75 nm PV (peak-to-valley) and less than 2 nm surface micro-roughness values are achieved which meets the stringent optical telescope specifications for terrestrial and space applications. The structural and nano-mechanical properties of presently developed SiO2 clad layer-based SiC telescopic mirror have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray Analysis (EDX), atomic force microscopy (AFM), and nanoindentation techniques. The optical properties are investigated by optical profilometry and wavelength based spectrometric (both in visible and infrared ranges) techniques. Finally, space worthiness studies viz., thermo-vacuum, thermal storage, thermal shock and relative humidity tests have been carried out successfully. The process of cleaning, grinding and polishing at each substrate preparation stage and coatings are also reported comprehensively.

In this present study hybrid aluminium metal matrix composites (HAMMC) were prepared by employing stir casting technique at 725 °C. Reinforcements such as Alumina (Al2O3), Silicon carbide (SiC) and Boron carbide (B4C) of 44µ size were reinforced with base aluminium matrix Al-6061 T6 alloy. Wear test, Tensile test, Flexural test and Impact test were done on the hybrid aluminium metal matrix composites as per ASTM standards. It is observed that hybrid composite with 2 wt% each of SiC, Al2O3 and B4C has high tensile strength and wear strength. Composite with 6 wt% of B4C has second high tensile strength, hardness and impact strength when compared with rest of the hybrid composites because of its excellent mechanical properties. Porosity of the samples 1 and 2 is less than the value 2.3 which indicates greater uniformity of reinforcements in the matrix. Flexural strength and Hardness was studied and analysed. Morphological study of the hybrid composites was done using Scanning Electron Microscope (SEM) observed minimal cracks on the surface of the samples due to wear test.

Bipolar plates (BPs) for fuel cell applications must meet minimum conductivity requirements while maintaining light weight and sufficient mechanical strength to be thinned and easily fabricated. Here, we prepare BPs comprising fluorinated ethylene–propylene (FEP), graphite flakes (GFs), graphite nanoplates (GnPs), and silicon carbide (SiC) particles for fuel cell applications. SiC particles decorated on large GFs and GnPs improve the flexural strength of the composites relative to the corresponding composites without SiC, resulting in increases of ∼24% and ∼130%, respectively. The improved mechanical properties of the FEP/GnP/SiC and FEP/GF/SiC composites are due to the uniform dispersion of SiC particles and strong chemical bonding between GF (or GnP) and SiC particles in the FEP matrix. Incorporating SiC particles into the FEP/GnP (or GF) composite plate provides a robust, scalable strategy for realizing high-performance, high-temperature fuel cell BPs.

This article presents a study on the electrification of reforming processes, in which the heat required for the reaction is directly supplied by the surface of the structured catalyst, realized by using commercial silicon carbide (SiC) heating elements as catalyst carriers, so eliminating all resistances to heat transfer. Three commercial ceramic supports were loaded with a 5 wt% nickel and tested in the steam reforming reaction. The best performance was obtained by the silica-mullite composite based support with the highest specific surface area. The structured catalyst was prepared by washcoating a SiC heating element, using a slurry based on the silica-mullite composite, subsequently impregnated in a solution of the nickel precursor, and tested in the steam and dry reforming reactions. The experimental tests were properly designed in order to reach the goals of (i) obtaining the kinetic parameters for the MSR reaction, and (ii) evaluating the energy consumption for both processes. The catalysts were characterized by means of X-ray diffraction, specific surface area, ED-XRF, SEM-EDS and Hg porosimetry. The results of the tests demonstrated that is possible to heat the system up to 800 °C, and sustain the reaction obtaining a methane conversion higher than 85 % both in the case of steam and dry reforming. The analysis of the energy consumption in terms of kWh Nm−3H2 has shown that it is comparable with the one of the modern electrolysers. The results of these experiments unequivocally demonstrate that it is possible to realize a process by reversing the flow of heat, from the inside of the catalytic bed to the outside.

Aluminum alloys are popular materials in industrial applications because of their higher specific strength to weight ratio and excellent mechanical properties. Various ceramics are added as reinforcement to improve mechanical characterizations of pure aluminum alloys and the newly synthesized material is recognized by aluminum matrix composites. Aluminum alloys have been used as matrix materials and materials such as aluminum oxide, magnesium oxide, boron carbide, silicon carbide, graphite, and fly-ash, and many more ceramics used as particulate reinforcements. The stir casting route is the most suitable, and ease of handling and economical methodology to develop the composites. In this review article, the influence of particle embedment and the predominant factors attributed to mechanical stirring during the processing of aluminum matrix composites are explored. Furthermore, the recent development and various parameters and related constraints that are also considered for improving the performance of aluminum matrix composites to be achieved in the future are also to be detailed in this study.

This work presents an experimental thermal evaluation of new and innovative porous morphologies suitable for volumetric solar receivers. Five new morphologies, four of them based on the repetition of single unit cells: diamond, rotated cube, tetrakaidecahedron, cube shifted, and a random morphology following the Voronoi tessellation technique were tested. In addition, for emerging geometries, two different cell size configurations were evaluated: one with constant cell size dimension and one with cell's size changing with flux direction. All the lattices were analysed experimentally in a lab-scale solar simulator. The results were compared with the ones of the already established and more conventional silicon carbide honeycomb and random foams proving that a gain in performance is achievable with the Voronoi morphology, both with constant cell size and increasing cell size pattern.

The development of materials for high temperature application posed challenges at all time. The present work deals with the development of copper – iron based material for brake pads preferably where the kinetic energy of vehicle is more at the time of halt. The copper powder approximately 60% of the composition along with iron, silicon carbide, graphite and barium sulphate are mixed thoroughly in a ball mill. These are new family of materials which possess same strength as ceramics and also possess good fracture toughness equal to that of metal. It is then compacted and sintered. After post sintering process the material is machined suitably and the test specimens are prepared for the wear test. The composite performs better at higher temperature and at lower sliding distance. The coefficient of friction shows a very gradual increase with the increase in time.

Aluminium (Al) as a matrix and the Silicon Carbide (SiC) as reinforcement is selected because of its high potential, low weight to high strength ratio, greater resistance to wear, lesser thermal coefficient of expansion makes it as a widely used composites in aircraft and automobile sector. The excellent mechanical properties of this combination enhances the mechanical properties with relatively less production cost making it as an important element for various applications from scientific and technological viewpoint. The Al-SiC combination is fabricated using stir casting process with various proportions of SiC. The Al-SiC fabricated Specimens are useful for aircraft and automobile sector. These specimens should be free from defects and should possess strong microstructure behaviours for longer life span. Proper observation and investigations are required for the micro structural characterization of Al-SiC such that Metal Matrix Composites (MMC’s) fabricated for aircraft and automobile sector should be considered. The main goal of this work includes the fabrication and micro structural study of Al 7075–SiC MMC’s. Aluminium 7075 is reinforced with various proportions of Silicon carbide in powder form of the order 20–40 μm in diameter (2 to 10 wt% in steps of 2%). The hybrid MMC’s is manufactured using liquid metallurgical technique also known stir casting technique. The resulting Al-SiC MMC’s structures are investigated by Scanning Electron Microscopy (SEM) and Power X-Ray Diffraction (XRD). The results obtained were analyzed. Finally a detailed comparison is made between the mechanical properties of base aluminum alloy and the prepared samples.

This paper presents the results of an in-depth study of the plasma-chemical etching (PCE) process of single-crystal silicon carbide (SiC) in SF6/O2 inductively coupled plasma (ICP). Using the method of optical emission spectroscopy (OES) we have examined the influence of RF power, bias voltage, pressure in the reaction chamber, and gas mixture composition on SiC PCE as well as the applicability of the OES technique for optimization and monitoring of SiC dry etching process in SF6/O2 ICP. An optimized PCE process for mass-manufacturing of SiC diaphragms of less than 20 μm thickness with an etch rate of more than 1.2 μm/min, and with an Rms of the etched surface of about 0.7 nm is developed. The influence of microtrenches on the electromechanical characteristics of the diaphragm as part of a capacitive pressure sensor is studied by means of computational simulation. An ideal diaphragm is compared with a real-process produced diaphragm with the microtrenching effect. It was shown that this effect has a great impact on the mechanical characteristics of the diaphragm. It is demonstrated that the von Mises stress at an applied pressure of 0.2 MPa for the real diaphragm is 183 MPa, while for the ideal diaphragm only 88 MPa.

The fatigue performance of metal matrix composites (MMCs) is highly related to their surface integrity due to the intensive tool-particle interactions and metallographic alterations of matrix, especially under extreme cutting parameters, which could largely result in surface morphologic defects and subsurface damage on the components. Although the fatigue performance of bulk MMCs has been extensively studied, the influence of machining-induced surface anomalies on the fatigue failure mechanism still needs to be understood. This paper investigates the effect of two distinct surface integrities induced by two cutting regimes (ductile, and semi-brittle regime) on the fatigue performance of MMCs. The ductile and semi-brittle regime were represented by different surface integrities regarding the particle behaviours and their effect on the mechanical and metallographic alterations of matrix materials. In-depth analysis in terms of surface topography, subsurface damage, and residual stresses of the machined workpieces has been carried out before the three-point bending fatigue test. The results showed that the samples machined by finish milling (very low feed – semi-brittle regime) unexpectedly presented lower fatigue lives compared to the rough-milled counterparts (high feed – ductile regime), despite the former displayed compressive residual stress and lower surface roughness. It was found that the particles have pronounced influence on the fatigue performance in two different ways: under low cycle fatigue, the particles were prone to be fractured by the high stress applied (which accelerated the formation of crack initiations and therefore shortened the fatigue life), while under high cycle fatigue, the reinforcement particles were not fractured and instead they could inhibit the crack growth up to some extent. Therefore, fatigue lives of the rough-milled samples (high feed – ductile regime) were enhanced due to the retardation of reinforcement particles.

In terms of fabrication and functioning, cantilevers are the simplest Micro Electro Mechanical Systems(MEMS) based devices. These cantilever based sensors have gradually progressed in all domain applications and may now found virtually everywhere. The usage of these MEMs based sensors is increasing gradually because of the distinct benefits that they provide. In high sensitivity applications like molecular sensing, microcantilever based sensors offer great promise for detecting a wide range of target atoms in gaseous and fluid medium as well chemical, and biological sensing applications. They too have an extensive range of applications in medicine, especially for early detection of more life-threatening diseases, identify intermolecular gene mutations, monitoring blood sugar levels, and detecting chemical and biological warfare agents. These cantilever based sensors offer numerous benefits over conventional diagnostic methods, including sensitivity, economical, easy to use, low analyte needed (in µl), non-hazardous procedures, and rapid response. In this study, we will explore the characteristics of two types of cantilever beams by modifying five types of materials, namely silicon, silicon dioxide and polysilicon, silicon nitride, and silicon carbide. Deflection properties are analysed by conducting a parametric sweep on arc length in order to build an array sensor. According to the simulation results the eigenfrequencies of the proposed array for the subjective load of 1Kda, 2Kda, 3Kda, 4Kda are 44 × 10 6 , 38 × 10 6 , 29 × 10 6 , 19 × 10 6 respectively.

In the present research work, an attempt has been made to fabricate graphene (Gr) and silicon carbide (SiC) reinforced aluminum (Al-5086) metal matrix composite (MMC) using friction stir processing (FSP) technique. The effect of FSP process parameters, such as rotational speed, traverse speed, and tool geometry, on the microstructure and mechanical properties, has been studied. The experiments were planned according to the L27 orthogonal array, based on Taguchi’s methodology. Microstructure, elemental, and phases composition of the developed composite has been examined using filed-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) technique, respectively. Mechanical properties, such as hardness and tensile strength, were determined using nano-indentation technique and tensile testing, respectively. The maximum micro-hardness and tensile strength of the FSP-processed composite have been found about 1.75GPa and 78 MPa, respectively.

In this study, the forms of occurrence of impurity elements in silicon carbide (SiC) with different particle sizes were systematically investigated using a combination of X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-OES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The experimental results showed that in SiC powders prepared using the Acheson process, the contents of O, free-Si, free-C, and Fe impurities are high, and those of other trace impurity elements follow the order: Ti > Al > Ni > V. Moreover, O impurities mainly cover the SiC particle surface in the form of amorphous SiO2. Fe impurities exist around SiC particles as Fe2O3, FexSiy, FexSiyTiz, and FexAlySiz phases. Impurity elements are often introduced during the smelting of SiC and/or during milling or subsequent storage.

Silicon carbide mixed electrical discharge machining (SCM-EDM), an unconventional machining process that utilizes an electrolyte mix additive, combines the advantage of various energies (abrasive, heat). The aim of these articles is to investigate the impact of control variables on the machining performance of SCM-EDM using LM-25/SiC MMC. The major variable of SCM-EDM is identified as current intensity, pulse duration. The experimental run has conducted as per Box- Behnken design which produces statistical data solely based on the experiment run and estimates the measurement error. Artificial neural network (ANN) technique implemented to estimate experimental inputs and modelling of measure response such as material deletion rate (MRR), tool wear (TW), and surface roughness (SR). It is observed that predicted results from ANN model are compared with experimental result are quite satisfactory. The chemical composition and analysis of variance show the percentage contribution of each parameter on machining performance.

A study of certain hardness and tensile properties of LM 22 reinforced with SiC and flyash to form a metal matrix composite (MMC) and is compared with the parent material. It was observed that the minimum value of hardness at 97.9BHN was the resultant of the composite with 5 percent reinforcement and post annealing. The value obtained in the hardness test had further minimized to 87.2BHN. The tensile strength test of the hybrid composite showed the result to have reduced from a value of 17.6 GPa to a value of 8.92 GPa which was achieved by adding the respective reinforcements into the composite and was observed to increase to 14.33 GPa with the increase in percentage of reinforcement beyond 4% Similar variation was witnessed in post weld specimens.

In this work, deposition time and RF power was shown to significantly influence the microstructure and properties of silicon carbide (SiC) thin films deposited on aluminum substrates by radio-frequency (RF) magnetron sputtering. Three different deposition times of 40, 60 and 75 min and at RF powers of 90 and 120 W were considered. The surface morphology of the thin films was investigated using an optical profilometer and a scanning electron microscope (SEM). The Vickers hardness test was also used to determine the hardness of the films. Grain size measurements revealed that increasing the deposition time and RF power results in larger SiC grains. Moreover, the surface roughness also increased with deposition time, however a decrease in roughness was observed when the RF power was increased from 90 to 120 W. The hardness of the SiC thin films generally increased with both deposition time and RF power, with the power having a more pronounced effect on the film hardness.

An ultra-precision machining approach called green-chemical-jump-thickening polishing (GC-JTP) is explored to improve surface accuracy and to achieve high-efficiency polishing for silicon carbide (SiC) ceramics. A new concept of green-chemical-jump-thickening polishing slurry (GC-JTPS) is developed to be an environmentally-friendly fluid with including two essential capabilities: one is the chemistry-induced jump-thickening (JT) mechanism and the other is green-chemical-thickening to enhance removal efficiency. Based on Navier-Stokes's equation and flow continuity equation, the polishing pressure in the GC-JTP process is calculated. On the basis of the rheological dynamics and abrasive nano-indentation analysis, a predictive understanding model to assess material removal rate (MRR) is proposed for the machining controllability of GC-JTP. Under the GC-JTP verification experiments, the maximal proportional error between the testing results and the theoretical calculation stands at only ζ = 7.8%, which proves the accuracy and effectiveness of the new theory MRR in GC-JTP. Through the fitting error, the correction coefficient of α = 0.929 should be used in the MRR model in order to better guide the actual processing. The analysis of the maximal cutting depth and the threshold of ductile-brittle transition revealing subsurface damages might generate. Under the optimized polishing conditions of the shearing velocity vr = 2.0 m/s, the abrasive size Da = 2.0 μm, the gap depth δ0 = 1.5 mm, the sodium bicarbonate Wp = 15 wt%, the sorbitol Wo = 20 wt% and the abrasive CeO2 Wa = 30 wt%, the SiC ceramics roughness is reduced from Ra 768 nm to Ra 32 nm and the subsurface damages depth can be controlled at the range of 2.5 μm–4.5 μm to achieve good surface integrity. The work demonstrates that the GC-JTP is a green and efficient processing method for the low-damage polishing of SiC ceramics.

High-energy continuous-wave (CW) laser has been considered as a significant technology in recent decades. Such laser can destroy conventional materials in an extremely short time, necessitating their protection. In this study, zirconium carbide (ZrC) and silicon carbide (SiC) particle-modified short silicon carbide fiber-reinforced phenolic resin matrix composites (SiC/BPF-ZS) with significant anti-laser performance were designed and prepared. Our results showed that the ceramic particles and SiC fibers rapidly oxidized, leading to the formation of a ceramic coating composed of ZrO2 and SiO2. Owing to the formation of the ceramic coating, the reflectivity of the composites improved significantly from 15.8% to 73.2% after ablation at 500 W/cm2 for 30 s. Additionally, the SiC fibers played an important role in the formation of a high-reflectivity coating during laser ablation. Contrast experiments indicated that SiC fibers lead to better performance than the carbon fibers. The high reflectivity and low mass ablation rate are demonstrated to be the key factors improving the anti-laser ablation performance of the SiC/BPF-ZS composites.

A novel ternary layered ceramic of Y3Si2C2 was successfully in-situ synthesized on the surface of home-made third-generation KD-SA SiC fiber for the first time by molten salt method aimed at improving the electromagnetic wave (EMW) absorption. After in-situ synthesis of Y3Si2C2 ceramic layer on SiC fiber (SiCf/Y3Si2C2), significantly improved EMW absorption performance was obtained. The minimum reflection loss (RLmin) of −16.97 dB was reached in SiCf/Y3Si2C2 composites at the thickness of only 2.19 mm, and the effective absorption bandwidth (EAB) was up to 5.44 GHz (12.56–18 GHz) at a thin thickness of 2.64 mm. The improvement in EMW absorption of SiCf/Y3Si2C2 is mainly attributed to enhanced dielectric loss and conduction loss resulting from increased heterogeneous interfaces and multiple reflections and scattering originating from net structure. The SiCf/Y3Si2C2 could be a promising EMW absorber for application in high-performance EMW absorbing materials.

This study proposed the methodology to produce silicon carbide particulate MMCs based on aluminum to create typical low-cost MMCs and achieve a homogeneous scattering of ceramic material. The trial was done with a different weight fraction of Silicon Carbide (2%, 3%) and Tungsten Carbide (2%, 3%) with all other parameters being maintained. A growing hardness was noticed with the rise in SiC & WC weight 2 to 3%. The advantages of this technique include improved mechanical characteristics, minimal residual stress and deformation, and fewer flaws. Although casting technique poses numerous technical obstacles, this problem can nevertheless be addressed. Aluminum materials with high strength to weight and low density have been proven to be the best option. As lightweight materials are developed, weight reduction has been offered several alternatives through conducting different tests to analyze different features such as mechanical and metallurgical characteristics.

A novel technique was proposed in this work to generate hypersonic water vapor plasmas in an inductively coupled plasma wind tunnel. Based on it, the oxidation behavior of a typical SiC coating was studied at varying heat flux in reduced pressure. The key observation is an accelerated corrosion of the SiC coating at

Poor antioxidant and thermal-shock capacities of C/C composites thermal barrier coating (TBC) caused by cracking and shedding of coatings has been a major obstacle blocking the development of C/C composites. Herein, in-situ growth of whisker reinforced silicon carbide transition layer and inter-embedding mechanism of multi-gradient coatings were brought into the design of TBC to enhance the antioxidant and thermal-shock capacities. A three-layer gradient coating SiC-SiCw/ZrB2-SiC/ZrSiO4-aluminosilicate glass (ZAG) from inside to outside, in which ZrB2-SiC/ZAG serve as oxygen barrier layers with self-healing ability and SiC-SiCw provides thermal stress buffering and bonding against cracking and shedding of coatings, is designed. The ZAG mainly forms a dense oxygen blocking frontier with self-healing ability through fluidized glass, while the ZrB2-SiC can react actively with infiltrated oxygen in a way of self-sacrifice, preventing oxygen erosion to C/C matrix and SiC-SiCw transition layer. As a result, the collaborative work among layers endows this coating with excellent high temperature service performance. This work provides a new insight for the design of excellent TBC.

Modern machining trends are continuously expanding nowadays, especially the various vibrational-based machining processes (VBM) exemplify as ultrasonic machining, ultrasonic vibration assistant machining, and rotary ultrasonic machining (RUM) processes. Therefore, this review study has been focused on these three machining techniques with an explanation of their parameters, physics, mechanism, and application. Also reported that the rotary ultrasonic machining and other vibration-assisted machining processes are used explicitly to machine hard, and brittle material exemplifies as ceramic, glass, bone, titanium alloy, silicon carbide, etc. There is a critical need for developing the models of process performances such as cutting force, tool wear rate, surface roughness, material removal rate, etc. Therefore, improvement in the USM, rotary ultrasonic machining, and UVA technique should be considered and explore the work up to an optimum machining limit.

The precise machining of silicon carbide composite (SiC–SiC) as a high-tech material with extraordinary characteristics is required for different applications in aerospace, light weight construction and car industry. Laser machining enable new approaches for fabrication processes but the regularly applied ablation processes can cause damage to the SiC–SiC material. Here we propose and demonstrate a new approach for gentle SiC–SiC machining making use of a laser-induced plasma for reactive species generation enabling chemical material removal processes. A fs-laser (775 nm, 150 fs, 1 kHz) was focussed to a CF4/O2 gas mixture igniting a laser-induced plasma (LIP) approximately 100 μm in front of a SiC–SiC sample. This LIP initiate material removal processes of the textured, multiphase SiC–SiC sample without a mechanical damage of the SiC–SiC composite structure. Different surface features such as etching of the cover SiC layer, etching of the SiC matrix and exposure, thinning and sharpen of the SiC fibres, underetching of the fibres has been observed. Across the whole etched area, no mechanical damage such as cracks, delamination's, broken fibres were observed so that a gentle machining process can be expected.

Al 7075 has potential applications in space, aircraft, marine, and automobile industries. So, the strength and wear resistance of the Al 7075 should be improved. Moreover, the strength and wear resistance can be improved by adding various ceramic particles, which are known as composites. Therefore, in the current research work, the reinforcements silicon carbide (SiC) ceramic particles with different wt.% (2, 4, and 6) are added with the matrix Al7075. Later, the mechanical properties like tensile strength and hardness of the fabricated composites are investigated. In addition to, the machinability (turning) characteristics of the fabricated Al7075-SiC composites are examined. Further, the response surface-based desirability function analysis is used to optimize the multi-objective like surface roughness (SR) and material removal rate (MRR). The results presented that the cutting speed and depth of cut contribute to maximizing the MRR and minimizing the SR of the developed composite. The optimal parameters for obtaining minimum SR and maximum MRR are cutting speed = 1500 RPM, feed = 0.15 mm/min depth of cut = 0.8 mm, and percentage of reinforcement = 3.24 wt%. Finally, regression models are developed and validated by confirmation experiments.

Carbon fiber reinforced silicon carbide (C/SiC) composites are usually subjected to thermal-mechanical-oxidation-coupled loads during service. However, their mechanical properties at ultra-high temperatures in oxidizing environments have rarely been reported. In this paper, a method based on the induction heating technology is proposed for testing the ultra-high-temperature mechanical properties of materials in air. The flexural behaviors of a 2D plain-weave C/SiC material prepared via chemical vapor infiltration are investigated in air up to 1800 °C for the first time. Inverse temperature dependences of the flexural modulus and strength are observed. New fracture mechanisms that are responsible for the mechanical behaviors at elevated temperatures are elucidated. Fracture modes at different temperatures are proposed. A high-temperature fracture strength model for oxidizing environments is developed, which is in good agreement with the experimental results. The factors affecting the fracture strength behaviors of the C/SiC in air at elevated temperatures are characterized quantitatively.