SiC Micro Research Articles

Phase separation during the direct powder bed fusion of SiC

AbstractPowder bed fusion (PBF) is an attractive additive manufacturing option for fabrication of SiC object with complex geometries. However, the density and microstructure controls remain a challenge. This study is aimed at understanding laser–SiC interactions, with emphasis on microstructure‐processing relationships, to identify potential solutions for the process improvement. SiC tubes were fabricated by PBF of pure SiC powders without sintering additives. Comprehensive analysis by X‐ray diffraction, Raman spectroscopy, and electron microscopy indicated that binding of SiC particles was achieved by incongruent melting of SiC to a Si/C mixture containing SiC micro‐ and nanocrystallites. The phase evolution under laser irradiation of SiC was explained by phase diagrams. This study uncovered the PBF SiC microstructure at different length scales and the relationship between the microstructure and the processing parameters.

Machine learning-assisted characterization of electroless deposited Ni–P particles on nano/micro SiC particles

In this experiment, Ni–P nanoparticles were deposited (ED) on SiC micro- and nanoparticles with different parameters. Our goal was to successfully prepare metal deposits and develop an effective method for comparing and evaluating the various procedures.During the experimental work, a three-step electroless Ni–P coating process was applied with different concentrations. The coated SiC particles were examined by scanning electron microscopy (SEM). The mass-specific surface area (SSA) of the coated SiC was measured by the Brunauer‒Emmett‒Teller (BET) method, while the volumetric-specific surface area (VSSA) was also calculated. The adhesion between the metal and the ceramic particle was analyzed by X-ray photoelectron spectroscopy (XPS).An image processing macroprogram was created (with a machine learning-based Trainable Weka Segmentation algorithm) to segment the SEM images of the ED metal particles to calculate the specific surface area (SV).

Casting A356+SiCp with ultrasonically treated melts

Low mass fractions (0.05 wt%) of SiC micro sized particles have been added to an A356 melt and dispersed by ultrasonic vibration to study their impact on the microstructural morphology of cast samples. It is shown that the ultrasonic melt treatment at 680°C can promote a homogenized distribution of the reinforcement while also degassing the melt and induces a moderate grain refinement. Even though SiC may act as a nucleant, its use did not induce a significant grain refinement relatively to ultrasonically treated unreinforced melts. Adding SiC microparticles, however, seems to enhance Eutectic Si modification, although it contributes to its slight coarsening at the expense of Mg2Si.

Crack suppression in glass epoxy hybrid L-bend composites through drawdown coating technique using nano and micro fillers

L-bend composite laminates are fundamentally weak against the crack growth in the through-thickness direction, particularly at the curvature region. To deal with this problem, an effort was made to suppress the crack growth by incorporating MWCNT, Al2O3, and SiC Micro fillers at the interface of unidirectional (UD) Glass fiber lamina, using a draw-down coating technique. The L-Bend Glass-Epoxy (GE) laminates were manufactured with the aid of a Hot pressing machine with a holding time being 10 min. The laminates were prepared with a manufacturing temperature of 130 °C and a pressure of 10 kg/cm2. GE curved laminates added with Nano and Micro fillers in the range of 0.5–2 wt% were manufactured. Four-point bending fixtures were designed and manufactured to facilitate the holding and loading of the specimen in the uni-axial tensile machine. Tests were conducted in accordance with ASTM D6415 and load-displacement plots were carefully recorded.GE laminates added with 0.5 wt% fillers greatly influence Curved Beam Strength (CBS) and interlaminar stresses for delamination as compared to pristine GE laminates. The laminates loaded with 0.5 wt% SiC exhibited higher interlaminar radial stresses (108.6 MPa) compared to other GE laminates.

Influence of SiC micro and nano particles on tribological, water absorption and mechanical properties of basalt bidirectional mat/vinyl ester composites

In recent years, basalt fiber reinforced polymer composites have gained popularity as an alternative to synthetic glass fiber reinforced polymer composites. Unidirectional 0°/90° basalt fiber-reinforced SiC micro and nano filled composites were tested for tensile, flexural, impact and hardness characteristics to determine the optimal composition. Comparing the mechanical properties of the composites reinforced various combinations of SiC micro or nano filler particles 4 wt% nano SiC filler addition exhibits superior properties. The scanning electron microscopy (SEM) images also reveals the improved interfacial interaction between the fiber mat and matrix for filler concentration up to 4 wt% SiC nanoparticles. Moreover, the wear resistance of the composites with 4 wt% SiC micro particles was better with low weight loss in wear test. The water absorption ability of the composite was low for the composites reinforced with 2 wt% SiC nanoparticles. Most of the properties of the composition with optimum filler addition are good enough for structural applications.

Silicon nitride–silicon carbide micro/nanocomposites: A review

AbstractThis paper reviews investigations of silicon nitride–silicon carbide micro–nanocomposites from the original work of Niihara, who proposed the concept of structural ceramic nanocomposites, to more recent work on strength and creep resistance of these unique materials. Various different raw materials are described that lead to the formation of nanosized SiC within the Si3N4 grains (intragranular) and at grain boundaries (intergranular). The latter exert a pinning effect on the amorphous grain boundary phases in the silicon nitride and also act as nucleation sites for β‐Si3N4, which limits grain growth during sintering. This finer microstructure results in strengths higher than for the monolithic silicon nitride. Intragranular SiC particles enhance strength and fracture toughness as a result of residual compressive thermal stresses within the nanocomposites. High temperature strength and creep resistance are also much higher than for monolithic silicon nitride and a few investigations of these topics are briefly reviewed and the proposed mechanisms are described. Within the context of other studies cited, work on Si3N4–SiC micro–nanocomposites by the current authors describes an aqueous processing route for better dispersion of commercial powders prior to sintering.

WITHDRAWN: Simulation of wear process parameters of hybrid aluminium micro composite using ANOVA

Aluminium hybrid composites are mostly required in industrial materials because of their combined properties. This Present paper Investigate wear behaviour of Al7075 Hybrid micro metal matrix composites SiC and Al2O3 micro particles. The composite prepared using liquid casting techniques stir casting which is the promising technique for aluminium MMC fabrication. Input experiment parameters considered as load applied, dry sliding velocity and sliding distance for conducting wear tests on pin-on-disc device. Parameters were taken in three levels as per L20 design and effect of these factors is observed by Analysis of variance modelling. Mathematical equations formulated by the modelling results and interaction of factors were studied.

Лазерный оптико-акустический метод количественной оценки пористости литых дисперсно-упрочненных металломатричных композиционных материалов

A laser optoacoustic method for quantitative porosity assessment of cast particulate reinforced metalmatrix composite materials is proposed and experimentally realized. The method is based on statistical analysis of the amplitude distribution of backscattered broadband pulses of longitudinal ultrasonic waves in the studied materials. Laser excitation and piezoelectric detection of ultrasound are realized by one-side access to a tested object using a special laser-ultrasonic transducer. Stir cast siluminmatrix composites reinforced with the SiC micro particles (volume fractions 0.033–0.135) and in-situ reactive cast aluminummatrix composites reinforced with the Al3Ti intermetallic particles (volume fractions 0.04–0.115). For both types of composites, the amplitude distribution of backscattered ultrasonic signals is approximated by the Gaussian distribution function applicable for statistics of large number of statistically independent variables. The derived empirical dependence of the half-width of this distribution on the volume porosity of two different types of composites is approximated by one and the same linear function independently of the fabrication technique, as well as on the type, size, and volume fraction of reinforcing particles.

Strain Modulation of Si Vacancy Emission from SiC Micro- and Nanoparticles.

Single-photon emitting point defects in semiconductors have emerged as strong candidates for future quantum technology devices. In the present work, we exploit crystalline particles to investigate relevant defect localizations, emission shifting, and waveguiding. Specifically, emission from 6H-SiC micro- and nanoparticles ranging from 100 nm to 5 μm in size is collected using cathodoluminescence (CL), and we monitor signals attributed to the Si vacancy (VSi) as a function of its location. Clear shifts in the emission wavelength are found for emitters localized in the particle center and at the edges. By comparing spatial CL maps with strain analysis carried out in transmission electron microscopy, we attribute the emission shifts to compressive strain of 2–3% along the particle a-direction. Thus, embedding VSi qubit defects within SiC nanoparticles offers an interesting and versatile opportunity to tune single-photon emission energies while simultaneously ensuring ease of addressability via a self-assembled SiC nanoparticle matrix.

Effect of porosity on the statistical amplitude distribution of backscattered ultrasonic pulses in particulate reinforced metal-matrix composites

This work aims at studying the effect of porosity in particulate reinforced metal-matrix composites on the statistical amplitude distribution of backscattered laser-induced ultrasonic pulses in these composites. A special laser-ultrasonic transducer used in experiments combines laser excitation and piezoelectric detection of broadband ultrasonic pulses in composite specimens with only one plane surface available for laser irradiation. We studied stir cast hypereutectic aluminium-silicon alloy A336 matrix composites reinforced with the SiC micro particles (volume fractions of 0.033–0.135) and in-situ reactive cast aluminum matrix composites reinforced with the Al3Ti intermetallic particles (volume fractions of 0.04–0.115). The amplitude distribution width of the backscattered ultrasonic pulse was determined by approximating the experimental data by the Gaussian probability distribution applicable for statistics of large number of independent random variables. The results show that the amplitude distribution width increases with the growth in the specimen porosity independent of sizes and fractions of the reinforcing particles. The empirical relationship between the local porosity and distribution width of the backscattered ultrasonic signal amplitudes was obtained for porosities up to 4.5%. This relationship can be used for nondestructive testing of the local porosity in engineering products fabricated from the studied composite materials. The proposed laser-ultrasonic technique is especially promising for structural health monitoring of particulate reinforced metal-matrix composites during their service.

Characteristics of composite magnesium with micro SiC particle for automotive applications with stir casting method

Composite is a promoted material consists of two or more materials to enhance the properties mechanically. In this study, composites were created by mixing a matrix; magnesium and the reinforcement; SiC microstructure with the addition of a volume fraction of: 2 %vf, 4 %vf, 6 %vf and 8 %vf. This magnesium composite fabrication process is stirred casting. The results of this study show that the addition of SiC micro particles will enhance the properties of the composite–mechanical wise-, namely, wear resistance and hardness. The addition of SiC micro-reinforcing particles that produced the best magnesium composite was by adding 8 %vf volume fraction which produced a hardness value of 83 HB and a wear rate of 0.002015706 mm3/m. Increased mechanical properties in magnesium composites is caused by the reducing grain size and Orowan strengthening mechanism.

Fabrication and Microstructure of Micro and Nano Silicon Carbide Reinforced Copper Metal Matrix Composites/Nanocomposites

This study investigates the influence of micro and nano silicon carbide on properties of copper matrix composites/nanocomposites containing up to 4 wt% of reinforcement concentration. It was observed that an increase of SiC (both micro and nano sized) content resulted in a higher hardness, compressive strength and better wear properties. However, nano SiC reinforced composite materials have better hardness, compressive strength and wear properties as compared with micro sized SiC reinforced composites. Grain refinement of composite/nanocomposite materials as compared with pure copper materials were observed from the metallurgical microscopic images. Further, scanning electron microscopic images revealed uniform dispersion/distribution of reinforcing materials in the copper matrix, and good bond formation between component materials. As the micro/nano sized SiC reinforcement in the copper matrix decreased the density of resultant composite/nanocomposite materials, therefore, nano sized SiC reinforcement will be helpful to fabricate light weight copper matrix nanocomposite materials for various industrial applications.

Mechanical and Tribological Properties of Al6063 Hybrid Composites Reinforced with SiC/ZrO2 by Stir Casting and Thixoforming Process

Hybrid metal matrix composites new generation of engineering materials with better mechanical and tribological properties. Al6063 alloy has the matrix material and reinforcement SiC and ZrO2 micro particles are selected for the study. In this work, Al6063/ SiC/ZrO2 hybrid composite fabricated with different wt. % of reinforcements (0.5, 1, and 1.5 wt. % SiC and 1 wt. % ZrO2 constant for all composites) by using stir casting process. The thixoforming process applied to casted composite. The SiC and ZrO2 particle was distributed in the Al-matrix are visible in the SEM micrographs .The hardness value of the composite 34.75% increased due to the addition of constant 1 wt. % of ZrO2 and varying SiC reinforcement particles. The charpy impact strength of Al composite was increased by 23.52 % with the addition of the constant 1 % wt. ZrO2 and 1 wt. % SiC particles. Wear behavior of Al6063/SiC/ZrO2 hybrid composite was tested using pin-on-disc machine. The wear volume loss decreased for 1.5 % wt. SiC and 1 wt. % ZrO2 compared to other composite. The worn surface morphology has revealed that Al6063 base alloy with deep groove. The composite with 0.5%, 1% wt. SiC and constant 1 wt.% ZrO2 showed more debris, dilamation and cleavage particles formed on the pin surface. The composite with 1.5 % wt. SiC and constant 1 wt.% ZrO2 showed less wear loss and smooth surface formation.

Effect of SiC micro and nanopowder in the electrical discharge machining process

EDM is used to machine difficult to process conductive materials through the conventional machining process. The concentration and particle size of powder shows different results. This research work has confirmed that nanopowder performs better than micro powder and conventional EDM. Enhancement in MRR observed by 12.12% and 57.14% compare to micro powder and conventional EDM, respectively. The surface quality also improved as average crater size enhanced by 34.04% from conventional EDM. Improved morphology of the machined surface analyzes through FE-SEM.

Influence of Friction Stir Processing Parameters on Mg ZE 41-SiC Surface Composite

In this study, the influence of friction stir processing process parameters (FSP), such as tool rotational speed, tool traverse speed, and the tool tilt angle on the mechanical properties of Sic reinforced surface magnesium rare earth ZE41 alloy composite was studied. The process was carried at tool rotational speeds of 710, 900, 1120, 1600, 1400 and 1800 rpm, tool traverse speeds of 16, 25, 40 and 63 mm/min and tool tilt angle of degree 1. Nano-particles of SiC (40 microns) were used as reinforcements to produce a composite surface. The grain refinement of the processed specimens was analyzed using scanning electron microscope. It is observed from the results that FSP process parameters influenced the surface composite area, SiC particles distribution and micro hardness of the composite. The outcomes indicated that the higher micro hardness was obtained at rotational speed of 1100 RPM, traverse speed 40mm/min and tilt angle 10.

Laser-ultrasonic nondestructive evaluation of porosity in particulate reinforced metal-matrix composites

In this work, we propose the laser-ultrasonic method for nondestructive evaluation of porosity in particulate reinforced metal-matrix composites fabricated by stir and in-situ reactive casting techniques. The method is based on the influence of porosity on dispersion of the phase velocity of longitudinal acoustic waves, which is measured by the broadband acoustic spectroscopy with laser excitation of ultrasound (laser-ultrasonic spectroscopy). We studied stir cast hypereutectic aluminum-silicon alloy A336 matrix composites reinforced with the SiC micro particles (3.3–13.5 vol%) and in-situ reactive cast Al/Al3Ti composites reinforced with the Al3Ti intermetallic particles (4–11.5 vol%). In the spectral range of 3–40 MHz, the phase-velocity dispersion in both types of composites was observed: the high-frequency velocity in the range of 20–40 MHz increases with the increase of the reinforcement content independent of porosity, whereas the low-frequency velocity in the range of 3–10 MHz decreases with the increase of porosity independent of the reinforcement content. As a result, the relative dispersion grows up with the increase in the composite porosity independent of the variation in the reinforcement content. The empirical dependence between the porosity in a scanning composite region and the relative phase-velocity dispersion in this region is approximated by the same unified function. For the first time, such unified porosity-phase velocity functional relationship is obtained for particulate reinforced metal-matrix composites completely different in fabrication techniques as well as in chemical composition and elastic properties of reinforcing particles.

Novel method for the production of SiC micro and nanopatterns

In this paper we report on a novel, large area method to produce SiC nano- and micro patterns at room temperature where the compound and pattern formation happens in one step. We have previously demonstrated that SiC can be produced by noble gas irradiation of a Si/C multilayer system utilizing the ion beam mixing (IBM) taking place at the interfaces. Here we show that by applying IBM in samples masked in any desired way patterned SiC surfaces, micro and nanostructures, result. Two different masking layers were applied to demonstrate the capabilities of the method; a Langmuir-Blodgett (LB) film of 590 nm silica nanoparticles and a lithographic grid, of 2 μm periodicity, mounted to the surface of a Si/C multilayer system. The systems were irradiated by Xe+ ions of 120 keV. The samples before and after IBM have been analyzed by AFM, SEM and AES depth profiling, proving that patterning occurred: the non-covered areas became SiC rich regions, while the covered areas remained untouched. As a possible application for the patterned samples, the gold-coated LB patterned nanostructure was used for surface enhanced Raman spectroscopic detection of an organic dye molecule (R6G) demonstrating the efficiency of IBM for producing SERS substrates consisting of a very stable compound like SiC.

Comparison of combustion efficiency between micro combustors with single- and double-layered walls: A numerical study

In this study, a micro combustor with double-layered walls was proposed for micro energy and power systems. SiC and quartz were selected for the inner and outer layers of combustor walls, respectively. Numerical investigation demonstrates that the double-layered micro combustor can achieve a higher combustion efficiency at large inlet velocity than single-layered SiC and quartz micro combustors. It is revealed that the heat recirculation effect of double-layered micro combustor is greatly enhanced compared to quartz combustor; meanwhile, the heat loss rate is decreased to some extent compared to SiC combustor. Moreover, the negative stretch effect at flame tip is reduced in the double-layered combustor. Consequently, combustion process can be intensified and flame tip opening can be alleviated, leading to a higher combustion efficiency in the double-layered micro combustor.

Electrodeposited Ni-B/SiC micro- and nano-composite coatings: A comparative study

Ni-B/SiC micro- and nano-composite coatings were electrodeposited in a modified watts bath containing SiC micro- and nano-particles with the average size of 3 μm and 100 nm, respectively. The chemical composition, SiC content; XSiC (wt.%), morphology, surface roughness, thickness, hardness and corrosion resistance of the deposited coatings were studied as a function of the particle concentration in the deposition bath (CSiC = 2, 4, 6, 8 g/L) and deposition current density (id = 0.5, 1, 2 and 3 A/dm2), using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Inductively Coupled Plasma (ICP), X-Ray Diffraction (XRD), microhardness measurements and potentiodynamic polarization (PP) tastings, respectively. The results indicated that the SiC content and surface roughness (Ra) of micro-composite coatings are increased with increasing both the CSiC and id and reached to the maximum of XSiC = 14.8 wt% and Ra = 4.58 μm at the CSiC = 8 g/L and id = 3 A/dm2. While the SiC content and roughness of nano-composite coating are initially increased and then decreased with increasing both the CSiC and id and the maximum of XSiC = 9.6 wt% and Ra = 2.28 μm were obtained at the CSiC = 4 g/L and id = 1 A/dm2. The thickness of both type of coatings increases almost linearly with id and micro-composite coatings exhibit greater thickness values. The nano-composites exhibit higher hardness and corrosion resistance than micro-composites despite having lower SiC contents. The maximum hardness and minimum corrosion resistance were 1035 HV and 0.03 μA/cm2 for micro- and 889 HV and 0.38 μA/cm2 for nan-composite coatings, respectively.

Cathode plasma electrolytic deposition of Al2O3 coatings doped with SiC particles

Semiconductor particles doped Al2O3 coatings were prepared by cathode plasma electrolytic deposition in Al(NO3)3 electrolyte dispersed with SiC micro- and nano-particles (average particle sizes of 0.5–1.7 µm and 40 nm respectively). The effects of the concentrations and particle sizes of the SiC on the microstructures and tribological performances of the composite coatings were studied. In comparison with the case of dispersing with SiC microparticles, the dispersion of SiC nanoparticles in the coatings was more uniform. When the concentration of SiC nanoparticles was 5 g/L, the surface roughness of the composite coating was reduced by 63%, compared with that of the unmodified coating. Friction results demonstrated that the addition of 5 g/L SiC nanoparticles reduced the friction coefficient from 0.60 to 0.38 and decreased the wear volume under dry friction. The current density and bath voltage were measured to analyze the effects of SiC particles on the deposition process. The results showed that the SiC particles could alter the electrical behavior of the coatings during the deposition process, weaken the bombardment of the plasma, and improve the structures of the coatings.