Steel Foam Research Articles

Efficient electrocatalytic nanocomposites of carbon nanotubes decorated with nickel selenides for urea oxidation reaction

In this study, carbon nanotubes (CNTs) coated with various phases of nanostructured nickel selenides were successfully synthesized with a simple and effective technique. These nanocomposites were then used as highly effective electrocatalysts for the urea oxidation reaction (UOR). The strategy involved depositing CNTs onto stainless steel (SS) foam using chemical vapor deposition, followed by pulse-reversal electrodeposition of nickel selenides in a layer-by-layer fabrication process. Different phases of nanostructured nickel selenides, such as NiSe2, NiSe2/Ni0.85Se, and Ni0.85Se, were successfully deposited on the surface of CNTs by controlling the reversal potential. Among all the different nanocomposites, the Ni0.85Se@CNTs-SS electrode exhibited the best electrocatalytic activity towards UOR. It required only a low overpotential, about 158 mV, to reach a benchmarking current density of 10 mA cm−2, and showed a low Tafel slope value of 85 mV dec−1. Additionally, the results of the prolonged stability study for 24 h confirmed the remarkable electrochemical stability of the Ni0.85Se@CNTs-SS electrode. After conducting stability studies, the overpotential shifted from 158 mV to 107 mV. This shift is due to the activation of the electrocatalyst during the stability test. The excellent electrocatalytic activity observed after the stability test is attributed to the presence of hydroxide and oxyhydroxide phases, which are remarkably active phases. This is the first-ever report where the Ni0.85Se@CNTs-SS nanocomposite electrode is shown to hold great potential as an effective electrocatalyst for UOR, which is an important step toward the design of a future electrocatalyst for UOR.

Experimental study on fundamental frequency and human‐induced vibration characteristics of light steel foam concrete composite floor

SummaryIn order to study the dynamic characteristics and human‐induced vibration response of light steel foamed concrete composite floor (LCSF), the vibration characteristics of 4.2 m × 5 m LCSF model were tested under the condition of opposite side support, and the natural vibration frequency of LCSF was obtained. The orthogonal anisotropic elastic plate and the simulated beam element were used, respectively, to compute the natural vibration frequency of the LCSF, and the estimated findings were compared with those obtained from measurements. The discrepancy between the calculated results and the measured results of the approximate beam element using the natural vibration frequency calculation technique is around 13%, but the error for the plate element using the calculated results and the tested results is about 23%. To examine the floor's vibration response under the factors of step frequency, walking path, pedestrian density, and load distribution, the LCSF underwent a human‐induced vibration test. The test results show that the fundamental frequency of the LCSF specimen is about 11 Hz, which can meet the requirements of the specification. However, the vibration response of the LCSF specimen under different conditions of pedestrian load is significantly different. With the acceleration of step frequency and the increase and concentration of load, the floor's vibration response becomes more visible. In the route test, it is established that LCSF has the attribute of a unidirectional plate. The natural vibration frequency of similar floor slab can be calculated by the method of simulating the natural vibration frequency of beam element. The findings can serve as a guide for LCSF research and implementation.

Impact response of lightweight steel foam concrete composite slabs: Experimental, numerical and analytical studies.

This paper presents a study on the low-velocity impact response of lightweight steel foam concrete (LSFC) composite slabs. The LSFC composite slab consisted of a W-shaped steel plate, foam concrete and oriented strand board (OSB). Low-velocity impact tests on the LSFC composite slabs were conducted by employing an ultra-high heavy-duty drop hammer testing machine. The tests revealed the failure mode, impact force and displacement response of LSFC composite slabs. The effects of density and thickness of foam concrete and drop height on the peak impact force and energy absorption ratio were investigated. A finite element (FE) model was set up to predict the impact resistance of the LSFC composite slabs, and a good agreement between simulation and test results was achieved. In addition, an equivalent-single-degree-of-freedom (ESDOF) model was set up to predict the displacement response of the LSFC composite slabs under impact loading.

Experimental and numerical investigation of integrated system between cooled photovoltaic and wall-inserted PCM/FOM thermal energy storage box

Photovoltaic cooling has become important in order to reduce the operating temperature and increase the electrical generation, efficiency, and useable time. The extract heat produced by this cooling process could either be used immediately or stored for later use. In this study, many goals were examined through experimental and numerical investigation. They included the effect of cooling the photovoltaic panels and the potential to use the heat removed by the PV cooling system as well as how to store it in a thermal energy storage box (TESB). This box, made of paraffin wax as a phase change material and supported by stainless steel foam, has been installed into a test wall for heating at later time. The test wall was a component of an insulated test room that was linked to the cooling systems of the photovoltaic panel, to be the integrated system. According to the study, there is plenty of potential for storing the heat energy that the PV cooling system removes and using it later from the thermal energy storage box. After using the integrated system, the mean useful energy increased by 83% from 39.2 W for the uncooled PV panel to 71.7 W for the integrated system. The maximum PV electrical generated outputs for uncooled and water-cooled panels were 40.9 W and 43.3 W, respectively. The efficiency of uncooled and water cooled PV panels was 14.2% and 14.7%, respectively and dramatically increased to 25.9% for the integrated system.

Production and electrochemical properties of the sol–gel α-Al2O3 coated stainless steel foams

Production and electrochemical properties of the sol–gel α-Al2O3 coated stainless steel foams

Synthesis of novel antioxidant carboxymethylcellulose nanocomposites for Cu–Ni–Mo-based steel foams

Synthesis of novel antioxidant carboxymethylcellulose nanocomposites for Cu–Ni–Mo-based steel foams

Dynamics of functionally graded beams carrying a moving load with influence of porosities and partial foundation support

The novelty of the present work is to study the simultaneous influence of porosities and partial Pasternak foundation support on dynamics of functionally graded (FG) beams carrying a moving load. The beams are made from an open-cell steel foam with symmetric and asymmetric porosity distributions in the thickness direction. Based on a refined third-order shear deformation theory, a two-node beam element with ten degrees of freedom is derived and employed to construct the discretized equation of motion for the beams. Dynamic characteristics, including the time histories for mid-span deflection, dynamic magnification factor (DMF) and the stress distribution, are computed with the aid of the Newmark method. The numerical result reveals that the foundation supporting length has an important role on the dynamics of the beams, and the dependence of the DMF upon the porosity coefficient is governed by the foundation supporting length. It is also found that the asymmetric porosity distribution has more impact on the dynamic response of the beams than the symmetric one does, and the difference between the DMFs obtained from the two porosity distributions is more significant for the beam with a higher porosity coefficient. The effects of the porosities, the foundation support and the moving load velocity on the dynamic behavior of the beams are examined in detail and highlighted

Experimental and numerical study on energy harvesting performance thermoelectric generator applied to a screw compressor

Abstract In this paper, an experimental and numerical investigation of thermoelectric generator for energy harvesting performance of screw compressors has been studied. The sources of heat recovery from compressors are recognized and a heat exchanger to mount the Thermoelectric Generator (TEG) module assembly is designed to adapt for implementation in this work. Computational fluid dynamics (CFD) is used to find out the temperature distribution in the heat exchanger and experimental work is carried out to validate CFD results. The heat exchangers, consisting of five TEG modules, temperature profile and voltage value have been studied numerically and experimentally. The parametric study has been studied to understand the influence of various system parameters on energy harvesting performance TEG based heat exchanger. An average of 1.6 V is generated by each TEG module and heat exchanger consists of five TEG and an average of 8 V is generated continuously by the heat exchanger. Also, it is proved that the usages of steel foam with 90 % porosity in heat exchanger improves the heat transfer rate and maximize the output from 8 V to 24 V in heat exchanger.

Linking Mesoscopic and Macroscopic Aspects of Inclined Self-Weight Sandwich Beams with Functionally Graded Porous Cores Under Moving Loads

The surging interest in porous lightweight structures has been witnessed in recent years to pursue material innovations in broad engineering disciplines for sustainable developments and multifunctional proposes. Functionally graded (FG) porous composites represent a novel way to adjust mechanical characteristics by controlling the porosity distributions. However, the further advance in this field is challenged by the scale gap between mesoscopic and macroscopic aspects of porous structural analysis, i.e. how the local cellular morphologies impact the overall behaviors. The purpose of this paper is to bridge this gap by conducting a theoretical investigation on the performance of inclined self-weight sandwich beams with FG porous cores, where Young’s modulus is obtained with representative volume elements (RVEs) in a multiscale modeling study and depends on the cellular morphologies: average cell size and cell wall thickness. The material properties of closed-cell steel foams are adopted in a two-step assessment on target beams, including a static calculation to examine their bending deformations under gravitational loading which are then imported into a forced vibration analysis considering constant and harmonic moving forces. Timoshenko beam theory is used to establish the displacement field, while Ritz and Newmark methods are employed to solve the governing equations in terms of bending, free vibration, and forced vibration. The inclined beams are assumed to rest on a Pasternak foundation, and the corresponding structural responses can be determined based on the specific cell size and cell wall thickness, of which the effects are quantitatively revealed: the stiffness degradation induced from cellular morphologies increases the dynamic deflections, while the corresponding self-weight static deformations are reduced and the fundamental natural frequencies are raised. The influence from geometrical, boundary, and foundation conditions is also discussed to provide a comprehensive overview. This will be valuable for engineers to develop devisable foam-based load-carrying components with enhanced properties.

Mechanical performance of reverse-engineered resin foam structures developed by image processing on the computed tomography data: A revisit

Using digital design methods, additive manufacturing processes enable us to create novel complex structures. In the current study, 3 and 10 ppi, density-graded, and merged foams (digitally joined 3 and 10 ppi) were reproduced from computed tomography data of the commercially available steel foams using MSLA (masked stereolithography). The mechanical performance of the foams has been characterized by quasi-static compression testing. Density grading increases the slope of the plateau regime and reduces the densification strain. Merged foams at high relative densities (ρrel∼35 %) showed the highest energy absorption capacity, specific strength, and densification strain. 3,10 and density-graded foams deform by bending of struts. In the case of merged foams, the bending-dominated structure has been transformed into a stretch-dominated structure. The power exponent (n = 0.72) delivers the deformation mode of the strut, revealing stretch-dominated behavior. Moreover, additively manufactured resin foams have a lower scattering in mechanical properties than conventionally manufactured metal foams because structures can be remanufactured with the same cell/strut dimensions and imperfections.

Assessing the Surface Properties of Plant Extract-Based Silver Nanoparticle Coatings on 17–4 PH Stainless Steel Foams Using Artificial Intelligence-Supported RGB Analysis: A Comparative Study

Assessing the Surface Properties of Plant Extract-Based Silver Nanoparticle Coatings on 17–4 PH Stainless Steel Foams Using Artificial Intelligence-Supported RGB Analysis: A Comparative Study

Silver flowers decorated open cell stainless steel foam for bone scaffold application

Silver flowers decorated open cell stainless steel foam for bone scaffold application

Compressive Properties and Energy Absorption Behavior of 316L Steel Foam Prepared by Space Holder Technique

The effect of porosity and pore size on the quasi-static compression properties and energy absorption characteristics of the steel foam was investigated in this paper. The 316L steel foams were prepared through powder metallurgy using urea as the space holder. The macrostructure of steel foam and microstructure of the pore walls were characterized, and the quasi-static compression experiments were conducted on the specimens in the axial direction at a strain rate of 10-3 s-1. The results show that the increase in porosity decreases the yield strength and plastic modulus of the steel foam but increases the densification strain of the steel foam. The yield strength of the steel foam decreases significantly when the pore size is 2.37 mm. However, the pore size has little effect on the plastic modulus. Moreover, the energy absorption per volume of the steel foam decreases with increasing porosity at the same strain. The effect of porosity on energy absorption efficiency is greater than that of pore size.

Characterization of Cr-Mo Alloyed Steel Foams Produced by Evaporative and Leachable Space Holder Techniques

Steel foams have attracted a lot of attention in both academia and industry with unique properties such as low density, high strength-to-weight ratio, operating temperature, good energy absorption, electrical conductivity, and large specific surface. The development of production methods will increase the use of steel foam. In this paper, Cr-Mo alloyed steel foams having porosities in the range of 46.8-71.3% were produced by evaporative and leachable space holder techniques in powder metallurgy. The effect on the properties of removing the carbamide used as a space holder material from the porous structure by different methods was compared. Microstructural evaluations of the pore wall, pore size, pore wall thickness, and the compressive deformation behavior of steel foam were evaluated. Steel foams produced by both routes have a rather similar macropore structure but differences in pore wall structure such as micropore ratio and pore wall thickness. The differences increase with increasing porosity content. The mechanical properties are higher in foams produced by the evaporative route as compared to the leachable route at similar porosity due to its stronger cell wall. The compressive stress and energy absorption of the leachable and evaporative process are in the range of 15-84 and 102 MPa and 1.91-6.03 and 2.98-7.83 J/mm2, respectively.

Micro and nano damage observations of martensitic and austenitic open cell cast foams

In current study a detailed investigation of the 304 austenitic and 420 martensitic foams damage has been carried out at all hierarchical levels. In-situ compression testing of foams and microtensile testing of single struts have been conducted in scanning electron microscope (SEM). Strain field analysis has been carried out by Digital image correlation (DIC) method. Nano damage has been applied by Nanoindentation on the unloaded and compressed foams. 304 foams depicted a ductile failure at each scale, while 420 foams failed with a tremendous brittleness, such that no real plateau regime has been observed. At microscale 420 struts ruptured with an intergranular cracking, while 304 struts underwent transformation induced plasticity (TRIP) effect with significant ductility. Although 304 steel struts have higher strength, 420 steel foams exhibited a higher strength due to their high hardness. Since there is not a plastic bending of the 420 struts, load is distributed homogenously to all struts. For this reason, it was concluded that the hardness and ductility of struts are the dominating factors in the foam deformation.

Effectiveness of heat sink fin position on photovoltaic thermal collector cooling supported by paraffin and steel foam: An experimental study

Forced convective cooling effectiveness on photovoltaic thermal collector electrical and thermal performance was experimentally studied with phase change material (paraffin) + steel foam mixture and two different angular positioned finned heat sink attachments. Fins are positioned flat and inclined, and air was forced with fan to flow between them. Solar radiation, temperature, electrical and thermal power, energy, and exergy efficiencies were determined and compared with reference photovoltaic module data. The first photovoltaic thermal collector was constructed with phase change material (paraffin) + steel foam mixture application to the back surface and covering with an incline finned heat sink. The second one was assembled with phase change material (paraffin) + steel foam filling to back surface and covering with a flat finned heat sink. Incline and flat finned heat sink attached collectors were cooled 12.23% and 21.67% relatively more than photovoltaic module. Electrical efficiency improvement with incline finned and flat finned heat sink application acquired approximately 5.09% and 6.18% relative to the photovoltaic module, which has 4.38% electrical efficiency, thanks to the cooling provided. The overall efficiencies were 41.4% and 59.53%. Photovoltaic module exergy efficiency is 4.67%, it is increased to 5.59% and 6.87% by cooling with incline finned heat sink and flat finned heat sink applications. Utilizable energy enhancement is identified approximately 140.32 kWh/year and 207.42 kWh/year by assuming 2738 h annual sunshine time in Turkey. These potentials rely on increase in electrical efficiency and heat recovery during cooling of PV/T collectors with incline and flat finned heat sinks. The predicted energy profit can be estimated at $7.01/year and $10.37/year, and its equivalent in emission reduction can be 115.76 kg·CO2/year and 171.12 kg·CO2/year.

The Microstructure and the Properties of 304 and 430 Steel Foams Prepared by Powder Metallurgy Using CaCl2 as a Space Holder

In order to prepare stainless steel foams (SSFs) with high specific strength, cost-effective performance, and multiple relative density ranges, this work used CaCl2 as a space holder to prepare 304 and 430 SSF samples with different relative densities using the powder metallurgy method. The microstructure and the properties were compared and analyzed by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and a universal testing machine. The results show that the matrix of 304 SSFs is austenite and 430 is ferrite. In the quasi-static compression test, when the relative density was in the range of 0.33~0.12, their compressive strength increased with the relative density increasing; the maximum compressive strength of 304 SSFs reached 40.29 MPa and that of 430 SSFs was 49.79 MPa. While the compressive strength of 430 SSFs is significantly higher than 304 SSFs at a similar relative density, 304 SSFs show better stability in the plastic deformation stage. When the deformation reached densification, the maximum energy absorption value of 304 SSFs reached 15.94 MJ/m3, while 430 SSFs was 22.70 MJ/m3. The energy absorption value increased with the relative density increasing, and 430 SSFs exhibited a higher energy absorption capacity than 304 SSFs.

In situ Growth of Ni(OH)2 Nanoparticles on 316L Stainless Steel Foam: An Efficient Three‐dimensional Non‐enzymatic Glucose Electrochemical Sensor in Real Human Blood Serum Samples

AbstractFor the first time, nickel hydroxide nanoparticles (Ni(OH)2 NPs) grown on 316L stainless steel foam were used as a non‐enzymatic electrochemical glucose sensor. The Ni(OH)2/SSF‐316L was elaborated by applying a simple ultrafast CV method without nickel salts addition. Ni(OH)2/SSF‐316L was characterized by SEM and XRD. The electrochemical behavior was investigated by CV, EIS, and amperometric measurements. The fabricated sensor revealed higher sensitivity 1062 μA mM−1cm−2, wide linear range from 1.0 μM to 4.0 mM with a low detection limit of 2.0 μM and good selectivity. In addition, real sample analysis was performed for controlled glucose in real blood serum.

Tensile Behavior and Performance of Syntactic Steel Foams Prepared by Infiltration Casting

Syntactic steel foams (SSFs) were prepared by low-pressure infiltration of molten ASTM CF-8 cast austenitic stainless steel into randomly and densely packed Al2O3 hollow spheres. The microstructure of the SSFs was characterized by scanning electron microscopy and energy dispersive spectrometry. Using dumbbell-shaped specimens, the density of the as-cast SSFs is measured in the range from 3.33 to 3.64 g/cm3 and their ultimate tensile strength from 83.1 to 97.6 MPa. No significant chemical reaction was detected between the fillers and matrix. The quasi-static uniaxial tensile deformation of the syntactic foams underwent elastic deformation, plastic deformation, and then a failure stage, showing similar tensile behavior to plastic bulk metals but different behavior to common metal foams. From the good ductility of the metal matrix, a clear macroscopic plastic deformation was observed before the ductile fracture of the syntactic foams. A constitutive relationship of the SSFs under uniaxial tensile loads has been proposed.

Air permeability and tensile properties of novel micron-scale gradient porous plates fabricated by rolling and vacuum sintering

A new type of gradient porous plate (GPP) was successfully fabricated by rolling and vacuum sintering using powders and wire mesh porous plates (WMPPs). The air permeability and tensile strength tests were carried out and the fracture morphology was observed. The results showed that the GPPs with low porosity not only had micron-pore structure with the pore size below 10 μm, and air permeability reached 1.27 × 10−13 m2, but also hold tensile strength with 257.8 MPa. Particularly, its air permeability and tensile strength were significantly superior to nuclear graphite, stainless steel foam, and porous alumina ceramics, equivalent to porous titanium. This study provides an effective method for the fabrication of micron-scale metal GPPs, and is of great significance for expanding the application range (especially in the fields of micron-scale precision filtration and the porous throttles of the aerostatic bearing) of porous materials.