Mixture Of Silicon Carbide Research Articles

Optimization of Process Parameters for Surface Roughness in Ultrasonic Machining of Polycarbonate Bullet Proof Glass and Acrylic Heat Resistant Glass by Taguchi and Grey Relational Analysis Approach

Polycarbonate bullet proof glass and acrylic heat resistant glass are used as the functional material in many application. In this research paper, Taguchi modal is utilized for the ultrasonic machining of these material. Surface roughness is significant output parameter, because it define accuracy of the process. Taguchi modal suggest that 40% concentration, mixture of Alumina, Silicon carbide and Boron carbide abrasive in 1:1:1, 600 abrasive grit size and 1.5% HF acid gives best results in polycarbonate bullet proof glass material and for acrylic heat resistant glass, mixture of Silicon carbide and Boron Carbide abrasive in 1:1, 600 abrasive grit size and 1% HF acid gives the best results. More significant parameters contribution in surface roughness are concentration of slurry, grit size of abrasive and HF acid. Optimum parameters improved the surface roughness by 23% and 24% in polycarbonate bullet proof glass and acrylic heat resistant glass respectively.

Mathematical Modeling for Material Removal and Optimization of Ultrasonic Drilling of Polycarbonate and Acrylic Glass for Surface Roughness by GRA Approach

Polycarbonate bullet proof and acrylic heat resistant glasses are used as the functional material in many industrial application. In automobile industries, banks and cabins, polycarbonate bullet proof glass has been used for security purpose. Similarly, acrylic heat resistant glass is used in furnace, microwaves, space craft and airplane applications. In this experimental research paper, Taguchi modal and Grey relational analysis are utilized for the ultrasonic drilling in these materials. For experimentation, input parameters are concentration, abrasive, grit size, power rating, hydrofluoric acid and tool materials. Output parameters are material removal rate, tool wear rate and surface roughness. In which, surface roughness is most significant output parameter, because it describe accuracy of the process. Through optimization analysis, Taguchi modal suggest that 40% abrasive concentration, mixture of (Alumina, Silicon carbide and Boron carbide) abrasive in 1:1:1, 600 grit of abrasive and 1.5% hydrofluoric acid gives best results for drilling in polycarbonate bullet proof glass material. Similarly, in acrylic heat resistant glass, mixture of Silicon carbide and Boron carbide (1:1), 600 grit abrasive and 1% hydrofluoric acid gives the optimum results. Concentration of slurry, abrasive grit size and hydrofluoric acid are the most significant parameters for ultrasonic drilling in both materials. Through Grey relational analysis the surface roughness is improved by 40% and 48% in polycarbonate (UL-752) and acrylic (BS-476) glass respectively.

Dry sliding wear behaviour of AA6082-T6/SiC/B4C hybrid metal matrix composites using response surface methodology

In the present work, dry sliding wear behaviour of hybrid aluminum metal matrix composites is carried out. A mixture of silicon carbide and boron carbide is used in equal fraction as reinforcement with base material AA6082-T6 to prepare AA6082-T6/SiC/B4C hybrid metal matrix composites using stir casting technique. The weight percentage of silicon carbide and boron carbide mixture taken to prepare hybrid composites is 5, 10, 15 and 20. The wear behaviour of Al-SiC-B4C composites is investigated using a pin-on-disc apparatus at room temperature, and optimization of process parameters is done using response surface methodology. The weight percentage of reinforcement, sliding speed, load and sliding distance are selected as process parameters with five levels of each. Analysis of variance shows that wear increases with increase of load or sliding distance and decreases with an increase in reinforcement or sliding speed. The experimental results revealed that the wear of Al-SiC-B4C hybrid composites has been influenced most by the sliding distance and least by weight percentage of reinforcement. The interaction between load–sliding speed is the only significant two-factor interaction in the present model which increases wear rate in fabricated hybrid composites. Further, the experimental results obtained are verified by conducting confirmation tests, and the errors found are within 3 to 7%.

Influence of the Sr and Mg Alloying Additions on the Bonding Between Matrix and Reinforcing Particles in the AlSi7Mg/SiC-Cg Hybrid Composite

Abstract The aim of the work was to perform adequate selection of the phase composition of the composite designated for permanent - mould casting air compressor pistons. The hybrid composites based on AlSi7Mg matrix alloy reinforced with mixture of silicon carbide (SiC) and glassy carbon (Cg) particles were fabricated by the stir casting method. It has been shown that the proper selection of chemical composition of matrix alloy and its modification by used magnesium and strontium additions gives possibility to obtain both the advantageous casting properties of composite suspensions as well as good bonding between particles reinforcements and matrix.

Preparation of Ti3SiC2 through reduction of titanium dioxide with silicon carbide

This paper describes the reduction of titanium dioxide with a mixture of silicon carbide and silicon powders at a temperature of 1550°C under vacuum. It has been shown that the use of the combined reductant enables the preparation of the ternary phase Ti3SiC2 through concurrent carboand silicothermic processes. The optimal compositions for Ti3SiC2 formation are TiO2 + (1.5–x)SiC + 2xSi with x = 0.4–0.5. The Ti3SiC2 yield then reaches 96 wt %.

Wettability of Silicon Carbide Particles by the Aluminium Melts in Producing Al-SiC Composites

The paper is a synthesis of essential data regarding the wetting conditions in aluminium – silicon carbide mixtures. Non wetting conditions between the reinforcing element and the matrix turns difficult the incorporation of particles in the aluminium melt. The wettability depends on several elements, like the presence of the oxide layer at the melt surface, temperature, pressure or shape of the complementary material. To improve wetting conditions, several measures are necessary: alloying of the melt with surface active elements, overheating of the melt; coating of the particles with a metallic thin layer. Also, by using existing data reported in the field, some parameters were calculated and interpreted.

Properties of SiC Ceramics Sintered via Liquid Phase Using Al2O3 + Y2O3, Al2O3 + Yb2O3 and Al2O3 + Dy2O3 as Additives: a Comparative Study

Silicon carbide (SiC) ceramics show excellent performance at high temperatures. Due to the high covalence of Si-C bonds, these ceramics are produced successfully only via liquid phase sintering (LPS). In this work, SiC ceramics were sintered via LPS using eutectic mixtures of Al2O3+Y2O3, which served as a standard for comparison, Al2O3+Yb2O3 and Al2O3+Dy2O3. The oxides mixtures were used to form liquid phase during the SiC sintering. Mixtures of SiC and additives were ground, pressed at 300 MPa and sintered at 1950oC for 2 hours. All mixtures showed similar hardness, fracture toughness and flexural strength slightly different. Also the microstructure and crystalline phase were similar, showing that the ytterbium's and dysprosium's oxides can be also used as additive as well the most used oxide, yttrium oxide.

Separation and Recovery of SiC Particles Discharged from Silicon Wafer Production Process

In the slicing process of silicon wafer from silicon single crystal, it has been the general way to cut silicon by wire saws with the lubricant mixture of silicon carbide, as SiC, particles and wrapping oil. After slicing the silicon single crystal, the waste liquor containing SiC and silicon powders is discharged from the process. The particle sizes of SiC and Si are about 10μm and 1μm, respectively and the weight ratio is about 9:1. The particles discharged from slicing waste liquor become the mixture of SiC and SiO2, when the waste liquor is burned after treating the lubricant oil by a filter press. In terms of the minimization of wastes and environment, it is preferable to separate and recover the valuable SiC from SiO2. In order to solve the problem mentioned above, flotation method can be applied to accomplish the separation of SiC from SiO2. The cationic surfactants of dodecyl-tri-methyl-ammonium chloride (abbreviated as DTMAC hereafter) and tri-methyl-octyl-ammonium chloride (abbreviated as TMOAC hereafter) were used in this study. The adsorption amount of surfactants on SiC and SiO2 particles was measured. The flotation behaviors of SiC and SiO2 were investigated by changing pH, gas flow rate and flotation time in the presence of DTMAC. The purity and yield of SiC were also discussed in the flotation process comprising of roughing, cleaning and scavenging steps. A series of flotation process for SiC gave the purity and yield of 99.7% and 96.7%, respectively.

Erosion behavior of SiC–WC composites

Dense silicon carbide (SiC) ceramics were prepared with 0, 10, 30 or 50wt% WC particles by hot pressing powder mixtures of SiC, WC and oxide additives at 1800°C for 1h under a pressure of 40MPa in an Ar atmosphere. Effects of alumina or SiC erodent particles and the WC content on the erosion performance of sintered SiC–WC composites were assessed. Microstructures of the sintered composites consisted of WC particles distributed in the equi-axed grain structure of SiC. Fracture surfaces showed a mixed mode of fracture, with a large extent of transgranular fracture observed in SiC ceramics prepared with 30wt% WC. Crack bridging by WC enhanced toughening of the SiC ceramics. A maximum fracture toughness of 6.7 MPa*m1/2 was observed for the SiC ceramics with 50wt% WC, whereas a high hardness of 26GPa was obtained for the SiC ceramics with 30wt% WC. When eroded at normal incidence, two orders of magnitude less erosion occurred when SiC–WC composites were eroded by alumina particles than that eroded by SiC particles. The erosion rate of the composites increased with increasing angle of SiC particle impingement from 30° to 90°, and decreased with WC reinforcement up to 30wt%. A minimum erosion wear rate of 6.6mm3/kg was obtained for SiC–30wt% WC composites. Effects of mechanical properties and microstructure on erosion of the sintered SiC–WC composites are discussed, and the dominant wear mechanisms are also elucidated.

Microwave heating characteristics of graphite based powder mixtures

The choice of material for a crucible is essential in hybrid microwave heating and graphite is one of the strong microwave absorbers which can sustain high temperatures. Experiments were carried out to investigate the microwave heating behavior of graphite combined with other materials to enhance efficiency. Mixtures comprising of graphite and magnetite or graphite and silicon carbide were found to have better microwave heating properties than pure components. The enhancement was likely due to microplasma generated by graphite in a microwave environment. Microwave heating of graphite–silicon carbide mixtures provided the best results in terms of high heating rates without arcing. The optimal combination of graphite–silicon carbide was identified and can be used as a starting material for making efficient crucibles and susceptors.

Ceramic Coatings and Glass Additives for Improved SiC‐Based Filters for Molten Iron Filtration

Reticulated silicon carbide (SiC) ceramic filters are prepared with modified coatings in an attempt to improve mechanical properties of the sintered filter. Two classes of coatings are used: mixtures of non‐SiC ceramic and sintering aid and mixtures of SiC and glass. Various candidate ceramics, sintering aids, and glasses are screened. The most promising coatings are determined to be silica with 5 wt% bismuth oxide and SiC with ≤10 wt% Spruce Pine Batch glass. Filters with these coatings are prepared and subjected to mechanical abuse. Both coatings improve the ruggedness of the filter relative to the standard uncoated SiC type. Filters with <10 wt% glass additive were subjected to molten metal impingement and filtration of liquid gray iron at 1510°C. Those with 5 wt% glass or more softened during filtration. Those with 2.5 wt% glass or less survived without failure.

The effects of nanoparticle addition on the densification and properties of SiC

The effects of nanoparticle addition on the pressureless sintering of injection molded and thermally debound silicon carbide (SiC) samples were studied. The influence of increased powder content and reduced particle size on the densification, microstructure and properties are discussed. The sintered parts of bimodal μ–n SiC mixtures exhibited comparable sintered density but lower shrinkage than the corresponding monomodal μ-SiC powder mixtures. Additionally, the mechanical and thermal properties of sintered monomodal and bimodal SiC samples were measured and compared with literature data for conventional monomodal μ-SiC systems.

Processing of Al/SiC composites in continuous solid–liquid co-existent state by SPS and their thermal properties

Silicon carbide (SiC)-particle-dispersed-aluminum (Al) matrix composites were fabricated in a unique fabrication method, where the powder mixture of SiC, pure Al and Al–5mass% Si alloy was uniquely designed to form continuous solid–liquid co-existent state during spark plasma sintering (SPS) process. Composites fabricated in such a way can be well consolidated by heating during SPS processing in a temperature range between 798K and 876K for a heating duration of 1.56ks. Microstructures of the composites thus fabricated were examined by scanning electron microscopy and no reaction was detected at the interface between the SiC particle and the Al matrix. The relative packing density of the Al–matrix composite containing SiC was higher than 99% in a volume fraction range of SiC between 40% and 55%. Thermal conductivity of the composite increased with increasing the SiC content in the composite at a SiC fraction range between 40vol.% and 50vol.%. The highest thermal conductivity was obtained for Al–50vol.% SiC composite and reached 252W/mK. The coefficient of thermal expansion of the composites falls in the upper line of Kerner’s model, indicating strong bonding between the SiC particle and the Al matrix in the composite.

A superficial coating to improve oxidation and decarburization resistance of bearing steel at high temperature

The coating material consisted of aqueous slurry of dolomite, bauxite and silicon carbide mixture. Such a coating material when applied superficially on the steel surface not only enhances oxidation resistance but also helps in inhibiting the decarburization even up to 1250°C. Metalloscope, XRD and TG-DTA thermal analysis revealed that the formation of a newly densified coating comprised of spinels and the reducing atmosphere formed by the oxidation of SiC improved the resistance of oxidation and decarburization.

Optimization of Friction and Wear Behaviour in Hybrid Metal Matrix Composites Using Taguchi Technique

Al-7075 alloy-base matrix, reinforced with mixtures of silicon carbide (SiC) and boron carbide (B4C) particles, know as hybrid composites have been fabricated by stir casting technique (liquid metallurgy route) and optimized at different parameters like sliding speed, applied load, sliding time, and percentage of reinforcement by Taguchi method. The specimens were examined by Rockwell hardness test machine, Pin on Disc, Scanning Electron Microscope (SEM) and Optical Microscope. A plan of experiment generated through Taguchi’s technique is used to conduct experiments based on L27 orthogonal array. The developed ANOVA and the regression equations were used to find the optimum wear as well as co-efficient of friction under the influence of sliding speed, applied load, sliding time and percentage of reinforcement. The dry sliding wear resistance was analyzed on the basis of “smaller the best”. Finally, confirmation tests were carried out to verify the experimental results.

Preparation of reaction bonded silicon carbide (RBSC) using boron carbide as an alternative source of carbon

RBSC composites are fully dense materials fabricated by infiltration of compacted mixtures of silicon carbide and carbon by molten silicon. Free carbon is usually added in the form of an organic resin that undergoes subsequent pyrolysis. The environmentally unfriendly pyrolysis process and the presence of residual silicon are serious drawbacks of this process. The study describes an alternative approach that minimizes the residual silicon fraction by making use of a multimodal particle size distribution, in order to increase the green density of the preforms prior infiltration. The addition of boron carbide provides an alternative source of carbon, thereby eliminating the need for pyrolized organic compounds. The residual silicon fraction in the RBSC composites, prepared according to the novel processing route, is significantly reduced. Their mechanical properties, in particular the specific flexural strength is by 15% higher than the value reported for RBSC composites prepared by the conventional approach.

Silicon Carbide as a Heat-enhancing Agent in Microwave Ablation: In Vitro Experiments

Silicon carbide (SiC) is an inert compound material with excellent microwave absorption and heat-conducting properties. The aim of our study was to investigate the heat-enhancing effects of SiC in microwave ablation in an in vitro setting. Different concentrations of SiC powder were mixed with 2% gelatin, producing a 20-ml mixture that was then heated with a clinical microwave ablation system (5 min/45 W). Temperature was measured continuously fiberoptically. Additional heating properties were assessed for the most heatable concentrations at different energy settings (10, 20, and 30 W). As reference, 2% gelatin without SiC was heated. Statistical evaluation by analysis of variance with post hoc Student-Newman-Keuls testing was performed. For the different SiC concentrations, maximum temperatures measured were 45.7 ± 1.2°C (0% SiC, control), 50.4 ± 3.6°C (2% SiC), 60.8 ± 1.8°C (10% SiC), 74.9 ± 2.6°C (20% SiC), and 83.4 ± 2.5°C (50% SiC). Differences between all data points were significant (P < 0.05). Maximum temperatures that used 20% SiC were 36.3 ± 2.76°C (10 W), 48.7 ± 4.18°C (20 W), and 50.6 ± 0.68°C (30 W). The use of 50% SiC maximum temperatures resulted in values of 46.2 ± 2.52°C (10 W), 70.1 ± 0.64°C (20 W), and 83.0 ± 4.69°C (30 W). With 20% SiC and 50% SiC mixtures, the 10 W maximum temperatures were significantly lower than at all other power levels, and maximum temperatures with 20 and 30 W were significantly lower when compared with 45 W (P < 0.05). SiC is a nontoxic, highly effective substance for enhancing microwave-induced heating with a microwave ablation system in vitro. These data suggest its usefulness for enhancement of ablative effects in percutaneous tumor therapy. Further investigations need to be performed to evaluate the ex vivo and in vivo ablation effects and the possible methods for administration of SiC particles.

High-pressure deflection behavior of laser micromachined bulk 6H-SiC MEMS sensor diaphragms

Single crystalline silicon carbide (SiC) in bulk or thin film form has the potential to be a durable and reliable MEMS pressure sensor in high-temperature and harsh chemical environments. Laser micromachining can fabricate SiC diaphragms for pressure sensors much faster than electrochemical etching, photochemical etching, or deep reactive ion etching without the complicated masking procedures that hinder mass production. In this paper, we present the deflection behavior of laser micromachined 6H-SiC MEMS diaphragms under high pressures and high temperatures. For this purpose, oversized MEMS square diaphragms, 1.5 mm × 1.5 mm and 2.5 mm × 2.5 mm, were intentionally built from bulk 250 μm thick single crystal 6H-SiC wafers using a Q-switched Nd:YAG laser with a wavelength of 1064 nm, pulse repetition rate of 3 kHz, pulse width of 100 ns, and average power of 0.35 W. The diaphragms had an average thickness of 100 μm that included a nearly 50% thick black layer composed of a complex mixture of Si, C, SiC 2, Si 2C, SiO and SiO 2. Pressure-deflection tests up to 425 K revealed that the diaphragms remained hermetically sealed under gas pressure as high as 3.0 MPa (435 psi) and that the black layer had a significant effect on the deflection behavior. An analytical model of bending thin plate under hinged boundary conditions and finite element simulations validated the experimental results.

Mechanical and Abrasive Wear Studies on Biobased Jatropha Oil Cake Incorporated Glass–Epoxy Composites

AbstractAn investigation was made to evaluate the effect of the incorporation of jatropha oil cake (JOC) alone and in combination with silicon carbide (SiC) on the mechanical and tribological wear behaviour of glass fabric–epoxy (GE) composites. A vacuum‐assisted resin transfer moulding (VARTM) technique was employed to obtain a series of GE composites containing different fillers viz., silicon carbide, jatropha oil cake and a mixture of SiC and JOC. The effect of different loads (22 and 32 N) and abrading distances from 135 to 540 m on the performance of the wear resistance of the composites were measured. The mechanical properties such as tensile behaviour and hardness of the composites were evaluated. A linear relationship was found between the wear volume loss and the abrading distances. The JOC filled GE composite exhibited a lower specific wear rate by 6 and 10% at 540 m abrading distance for a load of 22 and 32 N, respectively, as compared to that of unfilled GE composites. The worn surface features of unfilled and filled GE composites were examined using scanning electron microscopy (SEM).

Improvement of piezoresistance properties of silicon carbide ceramics through co-doping of aluminum nitride and nitrogen

The piezoresistance coefficient was measured on co-doped silicon carbide ceramics. Evaluation samples of α-silicon carbide ceramics were first fabricated by glass capsule HIP method using powder mixture of silicon carbide and aluminum nitride with various ratios. The resultant aluminum nitride added silicon carbide ceramics were doped with nitrogen by changing the post-HIP nitrogen gas pressure. The lattice parameter increased with the amount of adding aluminum nitride indicating that the incorporated aluminum substituted smaller silicon atoms. After post-HIP treatment, lattice parameter then decreased with nitrogen gas pressure. The piezoresistive coefficient increased with the addition of aluminum nitride, it further increased with the nitrogen doping pressure.