Effect Of Fabrication Method Research Articles

Effect of fabrication method and surface polishing on the surface roughness and microbial adhesion of provisional restoration

Effect of fabrication method and surface polishing on the surface roughness and microbial adhesion of provisional restoration

Multi-walled carbon nanotubes/woven glass/epoxy hybrid nanocomposites: Effect of fabrication methods and types of epoxy matrices

The hybridization of nanofillers into glass fibre reinforcement is a promising strategy to improve the properties of the composite materials. The study aims to investigate the properties of hybrid nanocomposites consisting of multi-walled carbon nanotube (MWCNT)/woven glass/epoxy composites. The effect of different fabrication methods and different types of epoxy matrices was also investigated. For method 1, MWCNT was mixed with epoxy and impregnated into 3-ply woven glass fabrics using the hand lay-up method, followed by a vacuum bagging process. Meanwhile, for method 2, the woven glass fabrics were spray coated with MWCNT aqueous suspension and 3-ply woven glass fabrics were stacked together and impregnated with epoxy using the hand lay-up method followed by vacuum bagging. Results showed that composite laminates prepared by method 2 with 0.5 wt% MWCNT exhibit higher impact and flexural strength with 32.9% and 29% increments compared to method 1, respectively. Based on the flammability test, it was observed that hybrid laminate composites fabricated by both methods could self-extinguish. It was found that hybrid laminated composites using bisphenol A as an epoxy matrix show higher impact strength and flexural strength with 20.7% and 12% increments compared to epoxy bio-resins, respectively.

Pitting corrosion performance of plasma oxidized Cp-Ti and effects of fabrication methods

In this study, the electrochemical corrosion properties of commercial pure titanium (Cp-Ti) samples produced by additive manufacturing and forging were compared by plasma oxidizing. Plasma oxidizing processes were carried out at temperatures of 650 °C and 750 °C for 1 h and 4 h. Electrochemical corrosion experiments were carried out in Simulated Body Fluid (SBF) using open circuit potential, cyclic potentiodynamic polarization and electrochemical impedance spectroscopy methods. It was found that the coating thickness of F 750 °C-4 h and S 750 °C-4 h samples was the highest. The corrosion resistance of the samples produced by additive manufacturing is lower than that produced by forging due to the Lack of fusion (LOF) effect. The barrier layer developed by the plasma oxidizing process significantly improved the corrosion performance of additive manufacturing by reducing the LOF effect. The minimum corrosion rate was obtained at S 750°-4 h. While the total material loss due to corrosion was the lowest on this surface, the last corroded surface was F 750°-4 h. The maximum resistance was observed on the plasma oxidized surfaces for the group produced by forging.

Mechanical Properties of PEMFC Electrodes According to Fabrication Methods

Electrodes in a polymer electrolyte membrane fuel cell (PEMFC) are the crucial element performing electrochemical reactions and are the most vulnerable mechanically. Various operating conditions (freeze-thaw, start-up, shut down) generate buckling, cracks, and delamination in electrodes. These mechanical failures not only directly affect the performance of the PEMFC cell but also act as a fatal factor in shortening the lifespan. Therefore, understanding and improving the mechanical properties of electrodes is essential for designing high-durability PEMFCs. Furthermore, the fabrication method of electrodes is a factor that causes not only performance but also distinct mechanical property differences since it determines their internal structure and surface characteristics. However, evaluating the mechanical properties of electrodes has been challenging because they are fragile and hard to separate from substrates. Therefore, this study evaluated the intrinsic mechanical behaviors of the electrodes according to fabrication methods via a free-standing tensile test. The effect of fabrication methods was analyzed for blade coating and spray coating methods used universally from industry to laboratory. The difference in mechanical properties between the two methods was identified by analyzing the internal structure and distribution of ionomer agglomerate. For blade-coated electrodes, modulus (372.5 MPa) and elongation (2.44%) were 2-2.7 times higher than spray-coated electrodes (172.9 MPa,0.9%). The difference in mechanical properties originated from the electrodes’ surface and internal structures. Blade-coated electrodes were composed of smaller pores and volume than the spray coating using FIB-SEM. The modulus ratio according to the internal structure through finite element analysis (using ABAQUS software) was consistent with the actual experimental value. In addition, blade-coated electrodes have high elongation and strength because they enable uniform stress transmission with a smooth surface and uniform ionomer binder distribution (analyzed by HAADF-STEM and EDS). This study contributes to a better understanding of the mechanical properties of electrodes according to the fabrication methods and provides guidelines for mechanical improvement. Figure 1

The effect of fabrication method on thermoelectric properties of Bi2Te2.7Se0.3 thin films

The effect of fabrication method on thermoelectric properties of Bi2Te2.7Se0.3 thin films

The effect of fabrication method on physical properties of different Y211 and 20% Ag2O added YBCO sample

The effect of fabrication method on physical properties of different Y211 and 20% Ag2O added YBCO sample

Directly Coated Iridium Nickel Oxide on Porous‐Transport Layer as Anode for High‐Performance Proton‐Exchange Membrane Water Electrolyzers

AbstractDeveloping a high‐performance anode design is important for a low‐cost proton‐exchange membrane water electrolyzer (PEMWE). In this study, an iridium nickel oxide directly coated anode (IrNiOx electrode) for high‐efficient PEMWE is reported. Five IrNiOx electrodes with different Ir‐to‐Ni ratios are developed using co‐electrodeposition. The resulting electrodes contain a thin IrNiOx layer on the carbon substrate. To develop the PEMWE incorporating IrNiOx electrode, the effect of fabrication methods, catalyst compositions, and porous transport layer are investigated. Consequently, the IrNiOx electrode prepared with 7:3 precursor solution (Ir0.5Ni0.5Ox) exhibits higher oxygen evolution reaction activity with a smaller overpotential than the electrode prepared with 10:0 precursor solution (IrOx) and the commercial IrO2. Furthermore, the performance of the PEMWE is higher with the Ir0.5Ni0.5Ox electrode than that with the sprayed electrode with commercial IrO2 nanoparticles. This enhancement is attributed to the high electrochemical surface area caused by introducing Ni in IrOx. Additionally, the performance of the directly coated Ir0.5Ni0.5Ox PEMWE is the highest reported in the literature.

Effect of fabrication method on the physical properties of carbon-nanotube/silicone-rubber nanocomposite in high-voltage insulators

Effects of fog condensation and fine dust on the high-voltage insulator surface are harmful. The insulator housing material (silicone rubber) must be changed in order to allow a controlled leakage current to flow on the surface and causes Joule heating effect. Accordingly, surface temperature of the insulator is increased and fog condensation on the insulator surface is prevented. For this purpose, silicone rubber - multiwalled carbon nanotubes (MWCNT) nanocomposites (SRCNT) were prepared using two different processes: a solution-blending (SB) method and a dry-state of melt-blending (MB) method. Field Emission Scanning Electron Microscopy (FESEM) images indicated that the MWCNT dispersion in silicone rubber matrix of SRCNT samples produced by SB method is much better than that of MB method. Fourier Transform Infrared (FTIR) spectroscopy determined the possibility of a greater reduction in hydrophobicity properties in the sample prepared by the SB method compared to the sample made by the MB method, and the contact angle measurements confirmed this expectation. Furthermore, in a same MWCNT concentration, the electrical conductivity of SRCNT samples prepared by SB method are greater than those produced by MB method. Results showed that MB is a high efficient method for producing the SRCNT in a large amount.

Properties of Y<sub>2</sub>O<sub>3</sub> Dispersion Strengthened W Fabricated by Ultrasonic Spray Pyrolysis and Pressure Sintering

The effects of fabrication method on the microstructure and sinterability of W-1 wt% Y<sub>2</sub>O<sub>3</sub> were analyzed. W composite powders dispersed with Y<sub>2</sub>O<sub>3</sub> particles were synthesized by the ultrasonic spray pyrolysis process or the ultrasonic spray pyrolysis/polymer solution process. A dense composite was fabricated by a combination of spark plasma sintering and final hot isostatic pressing. The powder synthesized by the ultrasonic spray pyrolysis had fine dispersed particles on the surface of the cubic powder and was composed of W, Y<sub>2</sub>O<sub>3</sub> and W-oxides. On the other hand, in the case of the ultrasonic spray pyrolysis/polymer solution process, the nano-sized particles formed agglomerates and existed only as pure W and Y<sub>2</sub>O<sub>3</sub> phases. All the sintered compacts treated with HIP showed an increase in relative density, and the sintered compacts of the powder synthesized by the ultrasonic spray pyrolysis/polymer solution process showed a maximum relative density of 97~99% and a fine grain size. The change in microstructure with different powder processing was explained by the presence of W-oxide and the size and distribution of Y<sub>2</sub>O<sub>3</sub> particles. The Vickers hardness of the sintered compact reached the largest value of about 5 GPa in the powder synthesized by the ultrasonic spray pyrolysis/polymer solution process, which was interpreted to be a result of the relatively high density and decreased grain size.

The effect of fabrication methods (conventional, computer-aided design/computer-aided manufacturing milling, three-dimensional printing) and material type on the fracture strength of provisional restorations

The effect of fabrication methods (conventional, computer-aided design/computer-aided manufacturing milling, three-dimensional printing) and material type on the fracture strength of provisional restorations

Effect of fabrication methods on the microstructure and properties of a Cu–Cr–Nb alloy

In comparison to other Cu-based alloys, the high-temperature strength of the studied Cu-4.06Cr-1.25Nb alloy fabricated by the atmospheric melting method was improved significantly. After homogenization at 950 °C for 4 h, hot rolling by 80%, solid solution treatment at 940 °C for 4 h, cold rolling by 50%, and aging at 400 °C for 2 h, the tensile strengths of the Cu-4.06Cr-1.25Nb alloy fabricated by spark plasma sintering (SPS) at 20 °C, 400 °C, 450 °C, and 500 °C were 535 MPa, 256 MPa, 212 MPa, and 165 MPa, respectively. While they were lower than the alloys fabricated by atmospheric melting at high temperatures, such as at 400 °C (285 MPa), 450 °C (266 MPa), and 500 °C (230 MPa), which could be explained by the grain boundaries strengthening of refined grains. At room temperature, the studied alloy fabricated by SPS had many refined grains, resulting in high tensile strength. However, the grain-refined/coarsened boundaries became the crack sources and the crack propagation paths, which were not conducive to the high-temperature strength. These findings are helpful in developing high heat-resistant Cu–Cr–Nb alloys.

Effect of Fabrication Method on the Thermo Mechanical and Electrical Properties of Graphene Doped PVDF Nanocomposites.

Nanocomposites of poly (vinylidene fluoride) PVDF with graphene nanoflakes (GNF) were prepared using two different routes. Initially, a mix-melting method was used to prepare composites, and their thermal and mechanical properties were evaluated to choose the better method for future experiment and properties investigation. Then, nanocomposite films were prepared by a simple solution-casting technique using a PVDF/graphene solution. In both cases, the amount of graphene was varied to observe and to compare their thermal and mechanical properties. The addition of graphene to the PVDF matrix resulted in changes in the crystallization and melting behaviors as confirmed by DSC analyses. Increasing the graphene content led to improved thermal stability of the PVDF nanocomposites prepared using both methods. Improvements in mechanical properties by the addition of graphene were also observed. Better performance was observed by the nanocomposites prepared by a mix-melting technique suggesting better dispersion and strong interface bonding between PVDF and graphene particles. Thermal and electrical conductivity were measured and compared. Microstructure and morphology were characterized using FTIR, XRD, and SEM analyses.

Oxidation Resistance in 1200\xb0C Steam of a FeCrAl Alloy Fabricated by Three Metallurgical Processes

FeCrAl alloys are a leading candidate material for accident tolerant fuel cladding due to their good performance in both normal light-water reactor operating conditions as well as their resilience to high-temperature accident scenarios. For commercial-scale production, new fabrication techniques need to be investigated. In this study, the effects of fabrication methods on the high-temperature steam oxidation performance of C26M (Fe12Cr6Al2Mo in wt.%) were investigated. Three variants of C26M were manufactured: wrought (cast and forged) (WC26M), powder metallurgy hot isostatic pressing (PMC26M), and laser powder bed fusion additive manufacturing (AMC26M). All three variants were exposed to steam at 1200°C for 2 h. Results showed no significant variation in mass change between the variants after steam exposure. All three variants effectively formed stable protective alumina films with ~0.6–1.3 µm thickness. This study suggests FeCrAl alloys have excellent resilience to high-temperature steam in nuclear reactor accident scenarios regardless of the fabrication method.

Effect of fabrication methods on microstructures, mechanical properties and strengthening mechanisms of Fe0.25CrNiAl medium-entropy alloy

The effect of fabrication methods on microstructures, mechanical properties, and strengthening mechanisms of high-entropy alloys has been systematically studied. In this work, a non-equiatomic Fe0.25CrNiAl medium-entropy alloy (MEA) was selected and fabricated by arc-melting, spark plasma sintering (SPS), and hot-press sintering (HPS). The results indicate that the fabrication method has little effect on the main phase compositions of Fe0.25CrNiAl MEA while marked impacts on microstructures, mechanical properties, and strengthening mechanisms. All alloys mainly consist of a disordered body-centered cubic (BCC) phase and an ordered body-centered cubic (B2) phase. However, the arc-melted alloy possesses a typical dendritic structure, while a speckle-like microstructure for the SPS-ed and HPS-ed alloys. Particularly the grain is refined dramatically by powder metallurgical methods of SPS and HPS. The yield strength of powder metallurgical alloys is over 400 MPa higher than that of arc-melted alloy, and without sacrificing the ductility (~30%). The strengthening mechanism analysis demonstrates that precipitate strengthening plays a significant role for arc-melted alloy while grain boundary strengthening is the dominant strengthening mechanism for powder metallurgical alloys. The Fe0.25CrNiAl MEAs by powder metallurgy achieve a trade-off between high strength and strain-to-failure, which suggests that the method is available for improving the mechanical properties of high-entropy alloys.

A systematic study on the effects of synthesis conditions of polyamide selective layer on the CO2/N2 separation of thin film composite polyamide membranes

AbstractDifferent top layer fabrication methods (amine‐first, acid‐first, spin coating), organic phase solvents (hexane, heptane, mixed hexane/heptane), acid acceptors (triethylamine, sodium carbonate, sodium hydroxide), and surfactant sodium dodecyl sulfate concentrations (0, 0.05, and 0.1 wt%) were utilized to fabricate thin film composite polyamide membranes for CO2/N2 separation. The results, according to an L9 orthogonal array of Taguchi approach, showed that employing acid‐first method increases both CO2 permeance and CO2/N2 selectivity of the membranes at a feed gas pressure of 3 bars. On the other hand, sodium hydroxide, and triethylamine should be used, as acid acceptors, to maximize CO2 permeance and CO2/N2 selectivity, respectively. Moreover, the use of hexane solvent and 0 wt% surfactant led to maximum permeance, while, hexane solvent and 0.1 wt% surfactant were needed to reach the highest selectivity. The above level setting of synthesis parameters also resulted in the minimum sensitivity of the fabrication process to the noise factors effects. As shown by the analysis of variance, acid acceptor, and organic solvent types were the most influential parameters on CO2 permeance and CO2/N2 selectivity, respectively. The effects of fabrication method and surfactant concentration, as single factors, on permeation/selectivity responses were also investigated.

Effect of Fabrication Method on Tensile Behaviour of Polysiloxane (POS) Filled Rice Husk Silica (RHA SiO<sub>2</sub>) Composites

The effect of fabrication methods on polysiloxane (POS) composites were studied by analysing both method of casting (CA) and compression (CO). The POS composites were reinforced with 2-12 wt% of natural derived silica from rice husk (RHA SiO2) as a filler which incinerated at 700°C. The composites behaviour were analysed through tensile testing (ASTM D412). Through comparison study on both CA and CO composites’s tensile behaviour it shows that both composites strength keep increasing with 2wt% - 10wt% RHA SiO2 addition but strength decreased at 12wt% due to agglomeration of RHA SiO2. Moreover, it was found that the tensile strength of CO composites had offer 23.56% higher compared to CA composites. The difference were influenced by the distribution of RHA SiO2 as filler. The surface morphology of CO composites had showed that the most of RHA SiO2 were embedded and less agglomeration, compared to CA composites that had lots of agglomeration which lead to higher tendency of crack propagation. The arrangement of filler due to the CO method that helps RHA SiO2 to distributed homogenously and embedded in a matrix of POS to avoid agglomeration and lead better adhesion respectively. Thus, CO method had potential to offer in enhancing tensile behaviour compared to CA method by influencing filler distribution arrangement for vibration absorber application.

Effects of Fabrication Methods on the Performance of Luminescent Solar Concentrators Based on Doped Polymer Optical Fibers.

In this work, we detail two types of fabrication processes of four polymer optical fibers doped with lumogen dyes. The fiber preforms have been manufactured with two different methods: extrusion and casting. We have compared the performance of the two types of fibers as luminescent solar concentrators by calculating their optical efficiencies and concentration factors. The obtained results show better performance for those fibers manufactured by the casting process. We have also studied the photostability of the two types of fibers doped with the dye lumogen red under solar light radiation. A high thermal stability of the doped fibers has been observed.

리튬 디실리케이트 크라운의 제작방법이 적합도에 미치는 영향

리튬 디실리케이트 크라운의 제작방법이 적합도에 미치는 영향

An Experimental Study on Force Acting and Effects of Fabrication methods on The Scaffold of Fibula Bone

An Experimental Study on Force Acting and Effects of Fabrication methods on The Scaffold of Fibula Bone

Effect of fabrication method on the structure and properties of a nanostructured nickel-free stainless steel

An ASTM F2581 nanostructured stainless steel was fabricated by two different powder metallurgy routes; Hot Powder Forging (HPF) and Binder Assisted Extrusion (BAE) methods. Their structure and mechanical properties were investigated and compared. In both fabrication methods, the alloy powder was made by using main alloying elements through mechanical alloying, along with the addition of a sintering aid. In the BAE method, a paste was prepared by mixing alloy powders with polymer followed by cold extrusion, polymer removal, and sintering. In the HPF method, the alloy powders were hot forged under high pressure. The structure and the size of the austenite crystallite of the samples were investigated by scanning electron microscopy (SEM), FE-SEM, x-ray diffraction (XRD) and transmission electron microscopy (TEM). It was determined that the samples prepared by the HPF method are generally denser than those made via BAE. The porosities are smaller and almost uniform in size and morphology in the HPF method. Furthermore, microhardness and tensile tests were performed on the samples. The results show that the ductility of BAE samples is higher than the HPF samples. The fracture surface of the BAE sample has deeper dimples, indicating higher ductility for BAE samples. On the other hand, both the hardness and strength of HPF samples are higher than those of the BAE samples. The results show that both methods produced specimens with considerably higher strength and hardness than conventional 316L stainless steel.