Silicon Carbide Powder Research Articles

Artificial neural network approach for the prediction of wear for Al6061 with reinforcements

In the prospect of finding a lightweight and wear-resistant materials, researchers have considered aluminium-based metal matrix composites (MMC), as aluminium has a wide variety of applications but possesses low wear resistance properties. To enhance the wear resistance of aluminium alloys, ceramic particles are reinforced. In this endeavour, commercially available aluminium alloy is reinforced with 2, 4 and 6 wt% of silicon carbide (SiC) and Vanadium pentoxide (V2O5) powder to improve its wear resistance. The intensity of reinforcement in the matrix was uniform, and the Scanning Electron Microscope image showed the grain refinement and grain boundary of the MMC’s. Wear tests were performed for L16 array set, uncertainty analysis of wear measurement is evaluated, and data were used to develop Artificial Neural Network (ANN) model. The efficient ANN model with a regression coefficient of 0.999 was used to make predictions for remaining sets. Experimental and predicted wear results were analysed; it is observed that higher wt% reinforcement of V2O5 increased wear resistance of aluminium compared to SiC. The methodology adapted using ANN for prediction of wear using meagre experimentation, will lay a path for tribologists to predict the wear of novel metal matrix composites in their endeavour of finding wear-resistant materials.

Effect of SiC Dispersed Composition on Physical and Mechanical Properties of Reaction-Sintered Silicon Carbide

Dense ceramic materials of silicon carbide with high mechanical properties are obtained by reaction sintering. The effect of different dispersed compositions of silicon carbide powders on the microstructure, grain size after sintering, and physical and mechanical properties is shown.

Production of silicon carbide reinforced molybdenum disilicide composites using high-pressure sintering

Studying the mechanical and thermal properties as well as the relationship between microstructure evolution and strengthening mechanisms is crucial for obtaining superior high-temperature refractory molybdenum disilicide-silicon carbide composites. In this study, molybdenum disilicide and silicon carbide powders with different volume ratios were used to fabricate molybdenum disilicide-silicon carbide composites via high pressure and high temperature at 5.5 GPa/1773 K. The introduction of the second phase improved the materials' mechanical properties. Transmission electron microscopy demonstrated that severe plastic deformation generated numerous micro-defects and grain refinement during the high pressure sintering process. The second phase enhancement also improved the samples’ performances. Under high pressure and high temperature sintering process, the thermal and mechanical properties of the materials increased dramatically, including a well Vickers hardness (~20.6 GPa), fracture toughness (~10.3 MPa·m1/2) and thermal stability (>1673 K).

Self-propagating high-temperature synthesis of silicon carbide nanofibers

The article presents the results of studies into the gas-phase synthesis of silicon carbide fibers using silicon powder, polytetrafluoroethylene (PTFE) energy additive and polyethylene (PE) powder by self-propagating high-temperature synthesis (SHS). Stoichiometric mixtures were used for experiments. Green mixture components were mixed in a 3 liter drum with tungsten carbide balls for 30 min. The green mixture weight was 500 g. Experiments were conducted in the SHS-30 industrial reactor. Silicon + PTFE mixture combustion was accompanied by a rapid increase in pressure from 0.5 to 4.0 MPa in less than 1 s, and a relatively rapid pressure drop to 1.5 MPa in 1.5 min. The combustion rate was more than 50 cm/s. It was established that there was a spread of the mixture components during the combustion due to the high combustion rate and intense gas emission. A cottonlike material of light blue color was obtained; it consisted of 100-500 nm thick silicon carbide fibers. The maximum pressure in the reactor reached 3.1 MPa in 1 s during the silicon + PTFE + PE combustion and then decreased to 1.5 MPa in 3 min. The combustion rate was about 40 cm/s. The entire volume of the reactor was filled with blue-grey cotton-like silicon carbide and SiC powder with equiaxed 0.5-3,0 μ m particles merged into conglomerates. Needle-like silicon crystals were formed in the transition layer between the powder and silicon carbide fibers. The results of experiments proved the possibility of obtaining silicon carbide nanofibers in relatively large quantities during the combustion of exothermic mixtures.

Studies on wire-mesh and silicon carbide particle reinforcements in explosive cladding of Al 1100-Al 5052 sheets

Abstract This study focuses on the development of stainless steel wire-mesh (WM) and silicon carbide particle (SiCp) reinforced hybrid aluminum composites with improved microstructural, corrosion and mechanical properties. Aluminum 5052-Aluminum 1100 sheets were explosively cladded with different reinforcements viz., stainless steel SS316 wire-mesh and silicon carbide powder (1.5 % and 3 % by weight of flyer plate) to produce composites at varied loading ratios, LR (Mass of explosive/mass of flyer plate=0.6 to 0.9), and the results are reported. Microstructural characterization of the conventional and wire-mesh reinforced clads display a slender melted layer, which transformed into a smooth interface when SiC particles are added as reinforcement. Maximum hardness is witnessed at the interface for the attempted conditions irrespective of the reinforcement employed. The explosive clad reinforced with wire-mesh and 1.5 % SiCp particles exhibit higher tensile and shear strength. The corrosion rate of the clad is higher in the initial days and tends to follow a uniform fashion afterwards.

Microstructural studies on aluminium metal matrix composite (Al7075-SiC) fabricated through stir casting process

In the present work Al7075 metal matrix reinforced with silicon carbide (SiC) powder is fabricated through stir casting route. Metal matrix composites were manufactured by altering percent weight fraction of silicon carbide powder as 5% & 7.5% by weight with average particle size of 50 µm. Microstructural evaluation and Vickers microhardness studies on stir casted Aluminium 7075 alloy which has silicon carbide (SiC) reinforcement are reported in current paper. After stir casting of composites, manufactured composite samples are examined by using optical microscope and scanning electron microscope (SEM) in order to study distribution SiC particles in aluminium matrix. The microstructural observations on metal matrix composites have reported the presence of SiC reinforcement in the matrix which are very much fairly distributed into the matrix phase. Also it can be seen that there is little clustering of SiC particles in Al7075 matrix and porosity in manufactured composites. It is also been found that microhardness of aluminium metal matrix composites was improved with increment in reinforcement content.

Nickel coating performance of porous SiC structures by electroless coating

In this study, the effect of nickel coating and performance of porous silicon carbide structures, by an electroless coating method, was investigated. Silicon carbide powders of 30 μm and bind bentonite powders of 20 μm were mixed, and a slurry was obtained. This mixture was then absorbed into the polymeric sponge template. The structures were kept in the furnace until 1300 °C; then both water and polyurethane were removed from the structure, and the remaining particles were sintered to each other. In order to improve the wetting behavior of the aluminum composite, the porous silicon carbide structures obtained were coated with the electroless coating method. AlSi10Mg aluminum casting alloy was infiltrated into the nickel-coated porous structures by a pressure die casting method. In order to examine the coating performance, microstructure, and element analysis, both porous silicon carbide structures and aluminum composites were performed. Density, according to the Archimedes principle, and porosity measurements were made on all aluminum composites. As a result, the positive effect of nickel coating on wetting in aluminum matrix composite systems was confirmed by obtaining a value close to theoretical density with 99.75%.

Fabrication and Property of SiC Ceramic with Large Thickness/Diameter Ratios

Silicon carbide ceramics with different thicknesses/diameter ratios were prepared by using ultra-fine silicon carbide powder with the sintering additives of 1.0 wt% boron and 1.5 wt% carbon. The influence of thickness/diameter ratio on the microstructure and density of SiC ceramics was investigated in detail. The experimental results show that the addition of boron and carbon sintering aids can promote the densification process of SiC ceramic, leading to the low sintering temperature and improve mechanical properties. At 1950 °C, SiC ceramic with a density of 99% exhibits Young’s modulus, hardness, and flexural strength of 476 MPa, 28.3 GPa, and 334 MPa, respectively. It is found that long holding time has a positive effect on the uniformity of the microstructure and density distribution of SiC ceramics with large thickness/diameter ratios. Additionally, the sintering additive of boron can solid-solve into SiC, and then facilitate the phase transformation of SiC to form 6H-SiC and 4H-SiC composite ceramics.

PROTECTION LOW CARBON STEEL FROM CORROSION USING COATING PROCESS

In this research work, samples of low carbon steel AISI 1017 subjected to shot peening process for 15 minutes. These samples were cleaned and coated with epoxy. The coating process were carried out with epoxy, epoxy mixed with alumina powder, epoxy mixed with silicon carbide powder and the last case, the steel coated with epoxy mixed with alumina and silicon carbide powders. Results showed that the corrosion resistance of steel coated with epoxy and alumina were better as compared with other samples .

Properties of composites SiC/SiCf obtained by hot pressing of SHS of silicon carbide powder

Dense ceramic samples based on SiC were obtained by hot pressing. We used the Use of silicon carbide powder as the initial components of SHS, due to the spherical shape of the particles, allows obtaining a denser workpiece. The reinforcing component in the form of silicon carbide fibers is obtained by siliconizing carbon fabric with SiO vapours. The phase composition of SiC fibers obtained by silicification by SiO vapour was determined. The properties of the obtained SiC/SiCf composites were studied: density 3.20 g/cm3, strength 520 MPa (for monolithic ceramics 390 MPa), the value of the crack resistance coefficient 5.9 MPa-m1/2.

Silica gel-coated silicon carbide layer deposited by atmospheric plasma spraying

Atmospheric plasma spraying (APS) of silicon carbide (SiC) is a challenging task due to the severe decomposition behaviour of the SiC. Previous studies, which utilized APS technique, mixed SiC powder with metals and/or metal oxides to prepare SiC coating. None of them sprayed silica gel-coated SiC and examined the characteristics of the coatings. In this work, silica gel-coated SiC, sodium dodecyl sulfate (SDS) enhanced silica gel-coated SiC, and the combination of alumina (Al2O3) and SiC were prepared and then deposited onto a titanium (Ti) plate by APS. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), adhesion and acid resistance test were performed to analyse the characteristics of modified powders and coatings. We found that compared to Commercial-SiC coatings, all the modified SiC coatings not only increase the coating thickness but also enhance the adhesion force between the coating and substrate; furthermore, the SDS-modified sample exhibits good sulfuric acid (H2SO4) resistance. On the other hand, samples containing Al2O3 showed a significant increase in coating thickness and adhesion force, despite a bit lower acid resistance. In sum, we believe that compared to silica-gel coated samples, Al2O3 contained samples are more suitable for industrial application.

Binder jetting additive manufacturing of silicon carbide ceramics: Development of bimodal powder feedstocks by modeling and experimental methods

A limitation of binder jetting additive manufacturing is the low density of fabricated parts. Mixing powders with different sizes is a promising approach to increase powder bed packing density and, hence, printed part density. However, in previous studies mixed powder feedstock was prepared by trial and error method. In this research, both modeling and experimental methods were used to prepare the bimodal powder feedstocks. Analytical packing model was introduced for irregular powders. A bimodal powder was prepared by mixing two different-sized silicon carbide powders (i.e. coarse and fine) using ball mill, and their tap densities were measured. Silicon carbide plates were printed using the coarse and bimodal powders by a commercial binder jetting system. Results showed that the modeling method could predict the tap density of bimodal powders with high accuracy. The printed parts from bimodal powder achieved higher green densities than those from the unimodal powder.

Investigation of the rubber elasticity and properties of polyurethane elastomers with different silicon carbide contents

Silicon carbide (SiC) powder was added to a polyurethane elastomer (PUR) to produce the composites. PUR was synthesized by mixing polyether polyol (PETP, Mw = 6000 g/mol) and 4,4′diphenylmethane diisocyanate. The stress-strain curves were carried out to estimate the effect of SiC on rubber elastic behaviour of PUR composites. As SiC content increases, the rubber elasticity region is noticeably decreased which can clearly be seen in the stress-strain curve, this could be attributed to the distribution of the SiC particles in the PUR matrix which prevents the cross-linking chain mobility of PUR and therefore affects the deformation while stretching. Furthermore, the decrease in the elongation at break is also co-related to the SiC content which hindrance the molecular mobility of the PUR chain. Shore A and D hardness increase by increasing SiC content up to 88 Shore A and 37 Shore D at 30 wt.% SiC. This is mainly due to the addition of SiC particles which act as active fillers in PUR matrix. The tensile strength and Young’s modulus are slightly increased when SiC content was increased. These observations support that Sick particles act as reinforcement which is active fillers and affect the stiffness in the elastic deformation of PUR.

Silicon carbide low temperature sintering: the particle size effect of raw materials and sintering additive

Aiming at dense sintering of silicon carbide ceramic, magnesium alloy powder was taken as additive, and silicon carbide powders with two different particle size were sintered by the same hot pressure sintering process. Result shows that ceramic sintered by the powder with larger particle size is denser. Magnesium and carbon segregation is observed in the sample prepared by powder with smaller particle size, in which silicon carbide particles cannot be uniformly dispersed by sintering additives. However, sintering additives distribute homogeneously among silicon carbide particles in the sample prepared by powder with larger particle size, which can effectively play a bonding role. In the selection of liquid phase sintering additives, particle size matching of raw material and sintering additives should be emphasized.

Using Porous Ceramic Catalytic Converters for Dehydrogenation of Propane in Propylene

Self-propagating high temperature synthesis (SHS) was used to obtain porous cermet membranes based on a mixture of aluminum oxide, silicon carbide, and magnesium oxide powders. The obtained membranes are catalytically active. The surfaces of the open pores in them were modified by rhenium-tungsten active components using the alkoxy method. The highest selectivity in terms of propane (about 60%) is achieved at temperature 600°C. In addition, the optimal conditions for implementing the propane dehydrogenation process is temperature 650°C at which the quite high selectivity for the most important monomers remains with a relatively small contribution of accessory processes.

Preparation of Silicon Carbide hollow fiber Membrane in Low Temperature by Precursor Pyrolysis

The silicon carbide (SiC) powder is covered with polycarbosilane (PCS), N-Methyl pyrrolidone (NMP) is a solvent, polyethersulfone (PES) is a bonding aid, using phase-phase and solid-phase sintering process combined with a step-by-step molding to prepare a symmetrical structure of silicon carbide hollow fibers, and determine the membrane’s perforation and purification and purity of the water distribution and the circumference of the membrane. The results show that the SiC membrane tube is a finger-hole structure layer-spongy structure layer-finger-hole structure structure, the optimal sintering temperature is at 1200 °C, the size of the prepared ceramic membrane aperture is concentrated in about 0.9 μm, and the pure water flux is 2.832m3 / (m2⋅h).

Study on Film Formation Properties of SiC Slurry

Two kinds of silicon carbide (SiC) powders with median diameters of 0.60μm and 2.04μm were selected as raw materials, and uniformly dispersed SiC coating film solutions were prepared through different particle grading. The effects of gradation ratio and dispersant tetramethylammonium hydroxide (TMAH) on the dispersibility and rheology of SiC coating films were studied, and the effect of dispersant content on the film forming properties of the slurry was discussed. When the fine powder and coarse powder grading mass ratio is 3:7, the particle size distribution of the mixed powder is closest to the theoretical distribution of the Dinger model. At this time, the slurry has good rheology and high particle bulk density. When 0.4% TMAH is added, the viscosity of the slurry is the lowest. When TMAH is added in an amount of 0.1 to 0.2%, the slurry has good film-forming properties.

Silicon Carbide particles dispersion Effect on the sintering behavior and damage characterization of Yttrium Oxide Composites Ceramics

Yttria, silicon carbide powders of (99.99) purity having (40-60) grain size were used to form different milling were done for all the combinations at 12 hours. Samples of disc shape were fabricated and sintered at different sintering temperature (800,1000,1200 and 1400) °C, respectively under static air and for three hours as soaking time. XRD test reflect the formation of new phase which is Y5Si3C (Unique). SEM test shows the sintering behavior after the sintering proses. Sintered samples were mechanically tested by hardness and fracture strength. Improvement was noticed for all the combinations after adding the dispersed SiC particles detected especially at the combination (Y2O3 80-SiC20) Wt.%, sintered at 1400 °C.

Investigation In to Some Electrical Properties of Ytteria – Silicon Carbide, Ceramic Composites

Ytteria, silicon carbide powders of (99.99) purity having (40) μm grain size were used to form different combinations of the system Y2O3- SiC. Silicon carbide particles was added in weight percent ranging (5,10,15and 20), dry milling were done for all the combinations at 8 hours. Samples of disc shape were fabricated and sintered at different temperature (800,1000,1200, 1400 and 1500) °C, under static air and for three hours as soaking time. Porosity for all sintered samples were measured. SEM after sintering were detected too. Electrical properties were studied to find the dielectric constant, breakdown voltage and the capacitance were don. Improvement in its electrical properties were achieved at all the combinations after adding the dispersed Sic particles. And especially at the combination (Y2O3 80-SiC20)Wt.%, that sintered at1500 °C.

Iron removal from ultra-fine silicon carbide powders with ultrasound-assisted and its kinetics

In the present work, the occurrence form of iron impurities of SiC crystals were analyzed using the field emission scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS), and the leaching kinetics of iron from the ultra-fine SiC powders in the acid system with ultrasound-assisted was also examined. The effects of the different parameters such as the types of acid, acid concentration, leaching temperature, reaction time, stirring speed, ultrasound frequency and power affecting on the iron removal efficiency were comprehensively studied to obtain an optimum condition. The results indicated that iron impurities are determined to exist in the form of FexSiy and Fex-Siy-Tiz phases in SiC crystals. Under the optimized conditions with ultrasound, the removal rate of iron can reach more than 92%. The leaching kinetics fit a homogeneous control model with the second order model as the rate-controlling step, and the activation energy of the ultrasound-assisted leaching process is determined to be 53.6 kJ/mol. The presence of the ultrasound can accelerate the leaching process and improve the iron removal efficiency, compared to conventional stirring.