Addition Of Nano-sized Particles Research Articles

Effect of addition of SiC and Al2O3 refractories on Kapitza resistance of antimonide-telluride

Invoking Effective Media Percolation theory (EMPT), Hasselaman-Johnson effective media theory (EMT), and Nan and Birringer EMT, the effect of addition of SiC and Al2O3 nanoparticles on Kapitza resistance (RBd) of Ni0.05Mo3Sb5.4Te1.6 was investigated. Pore size and their volume distribution, and surface area were characterized using BET technique to correlate pore effect and surface area on RBd. Bounds for effective thermal conductivity were determined using Lipton–Vernescu model. Variation of thermal conductance with respect to temperature was studied and compared with the results of other materials. According to EMPT, RBd in Ni0.05Mo3Sb5.4Te1.6/SiC composites ranged from 3.84 × 10-7 to 5.42 × 10-7 m2KW–1 and 3.36 × 10-7 to 3.86 × 10-7 m2KW–1 for Ni0.05Mo3Sb5.4Te1.6/Al2O3 composites. Kapitza radius (aK) for SiC samples was ranged between 2.01 – 2.84 μm; for Al2O3 samples it was 1.86 μm. Hasselman-Johnson model gave RBd values 55%, 51%, and 8% more than what EMPT is predicting, but of the same order and aK values 3.5 μm, 4 μm, 3 μm for SiC samples and 1.2 μm, 0.6 μm, 0.55 μm for Al2O3 samples. Nan-Birringer model yielded large aK of 7.25 μm and RBd ∼ 1.4 × 10–6 m2KW–1 for Ni0.05Mo3Sb5.4Te1.6/SiC. So obtained parameters are reasonable estimates. Variation of effective thermal conductivity in Al2O3 samples is more sensitive to particle size compared to SiC samples. Mechanical properties were studied using micro–indentation technique and their effect on effective thermal properties was ascertained. Addition of Al2O3 nanoparticles have aided in enhancing mechanical properties of bulk material.

The Effect of Laser Power on the Interface Microstructure of a Laser Remelting Nano-SiC Modified Fe-Based Ni/WC Composite Coating

The plasma sprayed Fe-based Ni/WC composite coating on the surface of 45 steel was post-treated by laser remelting with the addition of nano-SiC. The effect of laser power on the interface microstructure of a laser remelting nano-SiC modified Fe-based Ni/WC composite coatings were researched. The metallographic structure, microscopic morphology, phase composition, and microhardness of the remelted layer were visually analyzed by metallographic microscope, scanning electron microscope (SEM), X-ray diffractometer (XRD), and microhardness tester, respectively. The results showed that the nano-SiC modified remelted coating was smooth and compact, and with no fine cracks. The remelted layer was mainly composed of [Fe,Ni], Cr, Fe0.04Ni0.36 phase. The metal elements Fe, Ni, Cr, and Si, and non-metallic element C, appeared to diffuse, and there was metallurgical bonding between the coating and the matrix. With the increase of laser power, the smaller the average grain size, the wider the half-peak height (FWHM), and the more obvious the grain refinement. When the laser power was 500 W, the interface metallurgical showed the best effect. Furthermore, the nano-sized SiC particles served as the core of the heterogeneous nucleation to refine the grains on the one hand, and promoted the formation of a hard intermediate phase in the coating on the other hand. Therefore, the laser remelting and the addition of nano-SiC particles greatly improved the microhardness of the coating. The larger the laser power, the smaller the microstructure characteristics and the fewer the number of holes. With increasing laser power, the hardness increased in general terms and the maximum hardness increased by 51%.

Influence of SiC nanoparticles addition on the microstructure, thermal and tensile properties of Sn–Zn–Ag solder alloy

The effect of SiC nanoparticles (NPs) addition on the microstructure, thermal and tensile properties of Sn–Zn–Ag solder alloy (SZA822) was studied. Mechanical mixing technique has been utilized to disperse SiC in SZA822 at 673 K for 3 h. Microstructure analysis revealed the plain SZA822 and SZA822–0.5 SiC composite solders are mainly composed of Sn, IMCs of Ag3Sn & AgZn and Zn. But, after SiC addition, Ag3Sn particles were refined while AgZn partially dissolves in the Sn-matrix. One endothermic peak appeared in each solder alloy which confirms one-step melting. The melting temperature is maintained at the SZA822 level. Tensile results showed that the levels of the stress-strain curves were sensitive to the values of deformation temperature Td, strain rate and SiC loading. The ultimate tensile strength () increases while total strain (εT) decreases with SiC loading. So, SiC NPs act as a reinforcing agent. The strain rate sensitivity index (m) of composite solder was 0.09 and for SZA822 it was 0.11. Finally, the value of the activation energy Q of composite solder was 73.7 KJ/mole which is higher than that of SZA822 (61.7 KJ/mole). The Q values suggest that the dislocation motion mechanism is applicable in this work.

Higher intra-granular and inter-granular performances of YBCO superconductor with TiO2 nano-sized particles addition

The impact of titanium oxide (TiO2) nanoparticles addition on the intra-granular and inter-granular properties of YBa2Cu3O7-y (Y-123) were thoroughly investigated. Specimens were produced through the solid-state reaction (SSR) route by adding small contents of TiO2 nano-entities. The phase identification was studied using the X-ray diffraction (XRD). The microstructure and the chemical composition were examined by scanning electron microscope (SEM) technique coupled with energy dispersive X-ray spectroscopy (EDXS) system. The electrical resistivity measurements were done using the conventional four probe technique. The intra-granular, inter-granular and transport critical current densities of the synthesized specimens were explored through measurements of magnetization, ac-susceptibility and current-voltage, respectively. The possible pinning mechanisms predominant in synthesized compounds are estimated. The obtained results show that small amount of TiO2 nanoparticles improves the flux pinning capacity in Y-123 material.

Mechanical properties of Al-SiC Nano Composites fabricated by Friction Stir Processing

Aluminium metal matrix composites finds its application in aerospace, automobile, and energy industry owing to their excellent mechanical properties such as low density high strength, light weight, high strength-to-weight ratio and fatigue and corrosion resistances. Further the addition of nano size particles improves mechanical properties of the composites. The present work is focused on the mechanical performances of aluminium SiC nano composites. Instead of making bulk composites, the surface layers on the substrate improve the mechanical properties. For the fabrication of such surface composite layer, the new modification technique, friction stir processing (FSP) is used. FSP technique is used to produce defect-free surface composite with a good bonding and uniform distribution of reinforcement particles within an aluminium matrix. Various process parameters such as rotational speed, transverse feed, and volume fraction of nano SiC, on mechanical properties is investigated. The mechanical properties such as micro hardness and flexural strength were measured using micro hardness tester and universal tensile testing machine respectively.. In addition to that the morphology of the specimen is examined through scanning electron microscope to study them in detail.

The effect of SiC nanoparticles addition on the electrochemical response of mechanically alloyed CoCrFeMnNi high entropy alloy

The corrosion behavior as well as the electrochemical surface response of the novel CoCrFeMnNi (marked A1H) high entropy alloy (HEA) prepared by mechanical alloying of Co, Cr, Fe, Mn, Ni powders combined with Hot Isostatic Pressing (HIP: 1000 °C/15 min/150 bar) has been studied in chloride environment. Moreover, combination of the powder metallurgy and HIP allows to obtain HEA Metal Matrix nano-Composite (MMnC) with SiC nanoparticles addition as a reinforced phase. The influence of 5 %wt. SiC nanoparticles addition (specimen marked A1H5SiC) in A1H has been also investigated.Polarization tests indicate both passivation properties and pitting susceptibility of A1H alloy. This has been confirmed by the corrosion potential (OCP) and the electrochemical impedance spectroscopy measurements (EIS) which revealed strong passivation process in the first 16 h of immersion in 0.1 M NaCl water solution. The addition of 5 wt% of SiC nanoparticles improves the mechanical properties (e.g. hardness, yield stress) simultaneously changing the surface electrochemical response by the time reducing (from 16 h to 4 h) of the corrosion resistance during immersion in chlorides.

Experimental investigation on strengthening mechanisms in Al-SiC nanocomposites and 3D FE simulation of Vickers indentation

In the present study, Al-4%SiC nanocomposite was manufactured with homogeneous and uniform distribution of SiC particles in Al matrix using accumulative roll bonding (ARB) technique. In addition high strength Al sheets were manufactured using ARB technique with the aim of comparison. Tensile test and microhardness were used to characterize the produced nanocomposite. Moreover, 3D FE model is presented to predict microhardness of the manufactured nanocomposite. The results show that at the initial stages of ARB process, particle free zones as well as particle clusters were observed in the microstructure of the nanocomposite. After 9 ARB passes, Al-4%SiC nanocomposite with uniform distribution of particles was produced. The tensile strength for ARBed Al and Al-4%SiC nanocomposite after nine passes is 3.19 and 4.09 times of the annealed Al 1050, respectively. Moreover, microhardness of ARBed Al and Al-4%SiC nanocomposite after nine passes is 3.63 and 4.76 times of the annealed Al 1050, respectively. Interestingly, the main strengthening mechanism is the grain refinement and dislocation strengthening due to rolling process, while the addition of SiC nanoparticles acts as a secondary strengthening source. Finally, the microhardness results predicted by the presented 3D FE model correlate well with the experimental results.

Microstructure and Mechanical Properties of Al–SiC Nanocomposites Synthesized by Surface-Modified Aluminium Powder

Ceramic nanoparticle-reinforced aluminium metal matrix composites (AMMCs) have superior mechanical properties compared with matrix alloys, exhibiting great potential in structural applications in industries such as the aerospace and automotive sectors. This research proposes a new method for distributing SiC nanoparticles in an aluminium matrix alloy by powder metallurgy. The mixing of aluminium powder and SiC nanoparticles was processed by a two-step procedure, which included ultrasound-assisted stirring and planetary agitation. After that, the mixing powder was subjected to compaction, sintering and extrusion. A blank sample and three composite sheets containing 1, 2 and 3 wt % SiC nanoparticles were prepared and the mechanical properties were investigated by micro-hardness and tensile tests. A scanning electron microscope (SEM) and electron back-scattered diffraction (EBSD) were used for microstructural analysis of the composite. Experimental results revealed that by adding 1, 2, 3 wt % SiC nanoparticles, hardness was increased by 26%, 34.5%, 40.0% and tensile strength was increased by 22.3%, 28.6% and 29.3%, respectively. The grain size of the aluminium matrix decreased with the addition of SiC nanoparticles. Moreover, a decrease of elongation was observed with the increasing weight fraction of SiC.

Influence of SiC nanoparticles addition on microstructure and creep behavior of squeeze-cast AZ91-Ca-Sb magnesium alloy

The influence of SiC nanoparticles additions on the microstructure and creep behavior of the 2.0Ca + 0.3Sb (wt%) added AZ91 alloy fabricated by squeeze-casting have been investigated. For comparison, the same has also been studied without nanoparticles additions. The α-Mg, β-Mg17Al12, Al2Ca and Ca2Sb phases are present in both the alloy and the nanocomposites. The additions of SiC nanoparticles refined the grain size, reduced the volume fraction of the β-Mg17Al12 phase, and increased the amount of Al2Ca phase, which is more pronounced with an increase in the nanoparticle content. All the nanocomposites exhibit superior creep resistance than the unreinforced 2.0Ca + 0.3Sb (wt%) added AZ91 alloy. The best creep resistance is obtained in the nanocomposite pertaining 2.0SiC (wt%) nanoparticles. The values of stress exponents and the activation energies are in the range of 4.5–6.2, and 101.9 ± 2.5–115.5 ± 3.2 kJ/mol suggesting the governing creep mechanism for the alloy and the nanocomposites is dislocation climb controlled by pipe diffusion. The post creep microstructural observation confirms that the β-Mg17Al12 phase in the alloy is rigorously fragmented, and aligns in the direction of material flow, which deteriorates its creep resistance. In contrast, the presence of Al2Ca phase network and the SiC nanoparticles increase the dislocation pile-ups and dislocation tangling resulting in superior creep resistance of all the nanocomposites.

Preparation of Poly(o-ethylaniline)-SiC/Zinc Bilayer Coatings and Study of Its Corrosion Resistance Properties

The present work aims to study the differences of structure and corrosion resistance of poly(o-ethylaniline) (POE)-SiC/zinc (Zn) and POE/SiC-Zn bilayer coatings. Herein, POE and POE/SiC composite (PSC) were prepared by emulsion polymerization method, Zinc (Zn) and SiC/Zn composite coatings were prepared by electrodeposited technique. The structures of polymer materials were characterized by Fourier transformation infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), and the electrochemical behavior was studied by cyclic voltammetry (CV) measurement. Subsequently, the polymer materials were spread on the surface of electrodeposited coatings and thus obtained POE-Zn, PSC-Zn and POE-SiC/Zn bilayer coatings. The structures of Zn and SiC/Zn coatings were characterized by FTIR, XRD and energy dispersion spectroscopy (EDS) and the surface morphologies of all coatings were also studied by SEM. The corrosion resistances of the coatings were investigated in 3.5% NaCl solution by Tafel polarization curve and electrochemical impedance spectroscopy (EIS). It was shown that the addition of SiC nanoparticles to Zn matrix significantly changed the microstructure and improved the corrosion resistance. POE-SiC/Zn coating is more protective than PSC-Zn and POE-Zn coatings, with a corrosion rate of 0.021 mm/year and the corrosion protection efficiency up to 98.86%. The excellent corrosion protection of POE-SiC/Zn bilayer coatings was attributed to the fact that inner SiC/Zn coating possess a compact micro/nano surface, which facilitates the good embedding of outer POE coating and thereby eliminates the damage of the residual air in the grooves to outer coating. A conclusion was depicted that the protection is associated with the double barrier effects of outer/inner coatings and the passivation effect of POE. The protection mechanism conferred by POE-SiC/Zn bilayer coatings was also discussed.

Microstructural modification and strength enhancement by SiC nanoparticles in AZ31 magnesium alloy during hot rolling

Effects of SiC nanoparticles on the microstructural and textural evolutions of AZ31 matrix alloy during hot rolling were investigated. The addition of SiC nanoparticles can strongly inhibit the formation of shear bands, which are much more prevalent in matrix alloy sheets. Compared with pristine AZ31 alloy, the nanocomposite is characterized by a lamellar structure which is composed by the alternative a fine grain layer and a coarse grain layer. The lamellar structure was caused by the nanoparticle bands in as-rolled sheet. The fine grain layer was caused by the pinning effects of nanoparticles on recrystallized grain growth. Moreover, nanoparticles complicatedly altered the basal texture intensities of the matrix in the nanocomposite, instead of the reported simply weakening effect. For the mechanical strengths, the hot rolling leads to remarkable enhancement for both of nanocomposite and alloy sheets. However, the former ones always show superior value than the latter ones. Inhibited shear bands, nanoparticles bands and the associated lamellar structure do benefit the stronger mechanical properties in the nanocomposite sheets.

Enhanced performance of nano-sized SiC reinforced Al metal matrix nanocomposites synthesized through microwave sintering and hot extrusion techniques

In the present study, nano-sized SiC (0, 0.3, 0.5, 1.0 and 1.5vol%) reinforced aluminum (Al) metal matrix composites were fabricated by microwave sintering and hot extrusion techniques. The structural (XRD, SEM), mechanical (nanoindentation, compression, tensile) and thermal properties (co-efficient of thermal expansion-CTE) of the developed Al-SiC nanocomposites were studied. The SEM/EDS mapping images show a homogeneous distribution of SiC nanoparticles into the Al matrix. A significant increase in the strength (compressive and tensile) of the Al-SiC nanocomposites with the addition of SiC content is observed. However, it is noticed that the ductility of Al-SiC nanocomposites decreases with increasing volume fraction of SiC. The thermal analysis indicates that CTE of Al-SiC nanocomposites decreases with the progressive addition of hard SiC nanoparticles. Overall, hot extruded Al 1.5vol% SiC nanocomposites exhibited the best mechanical and thermal performance as compared to the other developed Al-SiC nanocomposites.

Interfacial properties and thermal aging of glass fiber/epoxy composites reinforced with SiC and SiO2 nanoparticles

Abstract The thermal resistance of glass fiber reinforced composites (GFRC) is often required for optimum performance. In the research reported in this paper two Si-type nanoparticles (SiC and SiO 2 ) added to GFRC were investigated. It was found that tensile and compressive strength of epoxy matrix composites changed with thermal aging. Differential scanning calorimetry (DSC) analysis disclosed that the epoxy-SiC composite had better thermal resistance than epoxy-SiO 2 . Microdroplet pull-out and short beam tests were used to determine interfacial shear strength (IFSS) and interlaminar shear strength (ILSS) between the epoxy matrix with the different Si nanoparticles and glass fibers. The reinforcing effects, the thermal resistance and the interfacial properties of the glass fiber/epoxy composites differed for the two types of Si nanoparticles, which was attributed to differences in their bonding. The addition of SiC nanoparticles produced the more thermal resistant composites, which is thought to be due to it inducing strong covalent bonding due to the “dangling bond effect” while SiO 2 induces rather weak hydrogen bonding by means of its oxygen. The SiC nanocomposites induced not only better thermal resistance but also better mechanical reinforcement.

Enhancement by SiC Nanoparticles of the Removal of Hydrogen Sulfide from Natural Gas by a Traditional Desulfurizer

With the purpose of comparing the effects on the absorption of hydrogen sulfide from natural gas of the addition of SiC (30-nm-diameter) nanoparticles into two common desulfurization solvents (TEA and MDEA), certain properties of MDEA-based and TEA-based SiC nanofluids were studied, such as the stability, rheological behavior, and thermal conductivity. Sedimentation experimental tests and zeta potential (ζ) results showed that the two types of nanofluids displayed ideal stabilities . Rheological measurements showed that the two types of SiC nanofluids were Newtonian fluids and that the viscosities of the TEA-based SiC nanofluids far outweighed those of MDEA-based SiC nanofluids. We also discovered that the thermal conductivities of the two types of nanofluids increased with the concentration. Dynamic experiments on the absorption of hydrogen sulfide from natural gas by MDEA-based and TEA-based SiC nanofluids showed that the desulfurization effect of MDEA-based SiC nanofluids exceeded that of TEA-based SiC...

Microstructure evolution and mechanical properties of Mg matrix composites reinforced with Al and nano SiC particles using spark plasma sintering followed by hot extrusion

In this study, Mg powders, Al and nano SiC particles were uniformly mixed by mechanical stirring assisted with ultrasonic vibration method. Then reinforced Mg-1Al-xSiC (x = 0.3, 0.6, 1.2, 2.4 wt %) composites were successfully fabricated by spark plasma sintering (SPS) followed by hot extrusion. Experimental results revealed that there was a nearly uniform distribution and good dispersion of nano SiC particles within the Mg matrix, although some of localized agglomerates were found in the matrix. Mechanical properties tests indicated that the addition of nano SiC particles along with 1.0 wt % Al particles to pure Mg resulted in a significant enhancement in tensile and compressive properties of the Mg-1Al-xSiC composites. Compared to monolithic Mg, Mg-1Al-1.2SiC composite exhibited higher 0.2% tensile yield strength (176 MPa vs. 98 MPa, increased by ∼80%), ultimate tensile strength (246 MPa vs. 188 MPa, increased by ∼31%), 0.2% compressive yield strength (140 MPa vs. 81 MPa, increased by ∼73%) and ultimate compressive strength (338 MPa vs. 255 MPa, increased by ∼33%) without much reduction on failure strain.

Opportunities for aluminum-based nanocomposites

High performance aluminum alloys are conventionally made by heat treating alloys containing a variety of alloying elements in solid solution. Key performance attributes are controlled at the microstructural level by tailoring sizes and morphology of nano-sized second phases. This enabled the successful development of aluminum alloys having properties optimized in strength, damage tolerance and corrosion resistance. However, this process is naturally limited by the solubility of alloying elements in the aluminum matrix. In real world products, significant effort is deployed to achieve a homogeneous distribution of the alloying elements both at the macro and micro scales. Despite these efforts, heat treatable alloys can exhibit chemical gradients at grain boundaries, resulting in sub-optimized properties. Additionally, due to the very nature of the strengthening mechanisms, the properties of heat-treatable alloys are decreasing when exposed to elevated temperatures. To step outside the boundaries given by the solubility of alloying elements in the aluminum matrix, the extrinsic addition of nano-sized particles to the aluminum matrix is being evaluated.

SiC Nanoparticles Toughened-SiC/MoSi2-SiC Multilayer Functionally Graded Oxidation Protective Coating for Carbon Materials at High Temperatures

A SiC nanoparticle toughened-SiC/MoSi2-SiC functionally graded oxidation protective coating on graphite was prepared by reactive melt infiltration (RMI) at 1773 and 1873 K under argon atmosphere. The phase composition and anti-oxidation behavior of the coatings were investigated. The results show that the coating was composed of MoSi2, α-SiC and β-SiC. By the variations of Gibbs free energy (calculated by HSC Chemistry 6.0 software), it could be suggested that the SiC coating formed at low temperatures by solution-reprecipitation mechanism and at high temperatures by gas-phase reactions and solution-reprecipitation mechanisms simultaneously. SiC nanoparticles could improve the oxidation resistance of SiC/MoSi2-SiC multiphase coating. Addition of SiC nanoparticles increases toughness of the coating and prevents spreading of the oxygen diffusion channels in the coating during the oxidation test. The mass loss and oxidation rate of the SiC nanoparticle toughened-SiC/MoSi2-SiC-coated sample after 10-h oxidation at 1773 K were only 1.76% and 0.32 × 10−2 g/cm3/h, respectively.

Enhanced photo-fermentative hydrogen production of Rhodopseudomonas sp. nov. strain A7 by the addition of TiO2, ZnO and SiC nanoparticles

In order to strengthen photo-fermentative hydrogen production by different photocatalytic nanoparticles, hydrogen production by photo-fermentative bacteria with addition of TiO2, ZnO and SiC nanoparticles in batch culture were investigated in this study. The results indicated that three nanoparticles could improve hydrogen production performance of Rhodopseudomonas sp. nov. strain A7 under respective optimal conditions. The hydrogen yield of 2.81 mol-H2/mol-acetate was obtained when TiO2 nanoparticles with a concentration of 300 mg/L and size of 25 nm. The concentration of ZnO nanoparticles was at 100 mg/L, hydrogen yield reached 2.64 mol-H2/mol-acetate. Compared with TiO2 and ZnO nanoparticles, SiC nanoparticles exhibited greatest potential for enhancing photo-hydrogen production. By addition of nano-SiC with concentration of 200 mg/L which was prepared at temperature of 1500 °C, the maximum hydrogen volume, average hydrogen content and hydrogen yield of strain A7 were achieved at 2272 mL-H2/L-culture, 85.2% and 2.99 mol-H2/mol-acetate, respectively. And hydrogen production was 18.6% higher than that of alone strain A7 without the addition of nanoparticles. Therefore, the addition of SiC nanoparticles is a promising strategy to improve photo-fermentative hydrogen production from wastewater.

Nanoparticle-induced unusual melting and solidification behaviours of metals

Effective control of melting and solidification behaviours of materials is significant for numerous applications. It has been a long-standing challenge to increase the melted zone (MZ) depth while shrinking the heat-affected zone (HAZ) size during local melting and solidification of materials. In this paper, nanoparticle-induced unusual melting and solidification behaviours of metals are reported that effectively solve this long-time dilemma. By introduction of Al2O3 nanoparticles, the MZ depth of Ni is increased by 68%, while the corresponding HAZ size is decreased by 67% in laser melting at a pulse energy of 0.18 mJ. The addition of SiC nanoparticles shows similar results. The discovery of the unusual melting and solidification of materials that contain nanoparticles will not only have impacts on existing melting and solidification manufacturing processes, such as laser welding and additive manufacturing, but also on other applications such as pharmaceutical processing and energy storage.

Effect of SiC nanoparticles addition on the microstructures and mechanical properties of ECAPed Mg9Al–1Si alloy

Abstract