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In this study, micron-sized flake shaped carbonyl iron (CI) water-based MR fluids were prepared with adding laponite and oleic acid as an additive and surfactant, respectively. The MR suspensions are comprised of the fixed CI particles and water weight %, while weight % of laponite and oleic acid changes from 1 to 3 wt% and 0.5 to 1.5 wt%, respectively. The remarkable enhancement in magnetorheological properties was obtained with improved sedimentation stability for CI/water MR suspensions with the addition of laponite and oleic acid. It was found that at the lowest magnetic field strength, the higher laponite concentration is effective, while at the highest magnetic field strength, the smaller concentration was effective. It was because of the combined effect of the field-induced CI chains and the laponite clay gel network. Its storage moduli showed a stable plateau area for whole angular frequencies, suggesting distinguished solid-like behavior of the MR fluid. Finally, a novel correlation was obtained between the initial settling rate of the CI particles and magnetorheological behavior of CI/laponite/OA MR suspensions with 1 wt% laponite and 0.5 wt% oleic acid, which has less zero-field, high on-state shear stress with enhanced sedimentation stability. The prepared MR fluids are a reliable industrial application vibration-isolation, clutch, and brake.

This work examines magneto-rheological elastomers (MREs) based on isotropic and anisotropic distribution of carbonyl iron particles (CIP) in natural rubber (NR) and acrylonitrile butadiene rubber (NBR). Measurements of the compressive mechanical properties were done to determine the isotropic and anisotropic properties of the MREs. Scanning electron microscopy (SEM) and optical microscopy were employed to study the CIP filler mixing behavior in the rubber matrix and orientation of particles in an anisotropic state. CIP-NBR composites show higher ultimate compressive stress in both isotropic and anisotropic states than NR-based composites. NBR-based composites show positive increases in both the elastic modulus and compressive stress at higher deformation when changing from isotropic to anisotropic, whereas NR-based composites show a positive increase in the elastic modulus and a decrease in the compressive stress. Elastic modulus measurements of anisotropic composites under a magnetic field suggest that NBR composites have much better field-dependent magnetic properties than NR composites. Anti-stress-relaxation measurements indicate that NBR composites have better magnetic effect than NR composites. The better performance of NBR-based anisotropic composites in field-dependent and independent behaviors might be due to better filler distribution, a greater number of chain-like filler structures, and less aggregation of the chain-like filler strands. The MREs based on NBR could be more useful than NR for wide range of magneto rheological applications.

This work describes the influence of VK carbonyl iron powder on the properties of 60Kh2N steel powder. It has been demonstrated that addition of the VK powder to sprayed powder of grade PZhRV 2.200.26 in an amount up to 15% makes it possible to increase the tensile strength from 417 to 482 MPa because carbonyl iron in combination with carbonyl nickel powder in coarse pores between the particles of sprayed iron forms a sintered frame, which positively influences the strength of the obtained material. The mechanical properties of this steel have been improved by hot rolling with subsequent annealing in a protective environment. As a consequence of this additional treatment, the ultimate tensile strength reached 595 MPa.

Magneto rheological fluids, often called smart fluids, play a significant role in effective mechanical braking systems, haptic devices, mechanical dampers and other mechanical devices. Presently, the properties of Magneto rheological fluids added with additives or nanoparticles were discussed. The introduction of an additive/nanoparticle in MR fluid alters the mechanical, thermal, structural and other properties of the fluid. The characteristic feature of this fluid is that they become solidified under the effect of an applied magnetic field. This is mainly due to the chain development of suspended molecules in the fluid medium. When these fluids are mixed with nanoparticle additives, these chain forms become stronger, as the nanoparticles occupy the spaces among the molecules of MR fluid. This in turn increases the dispersion stability, yielding strength of the fluid under action. Due to higher solubility of suspended iron particles, the Carbonyl Iron based MR fluid is the most commonly used MR fluid.

MR fluids face a major problem of sedimentation rate due to the high- density difference between the magnetic particles and the carrier medium that affects the performance of the magnetorheological devices. In this work, two MRF samples are prepared, where MRF-1 and MRF-2 are pure and coated carbonyl iron particles (CIPs) based MR fluids. The surface modification of the CIPs is performed using the solvent dispersion method to improve the sedimentation rate. The spherical shape and particle size analysis of the pure CIPs and coated CIPs’ morphology is investigated using the Scanning Electron Microscope (SEM). The Thermal Gravimetric Analysis (TGA) shows that the coated CIPs have high thermal stability and confirm that 6% by wt. coating is present in the coated sample. The chemical bonding of the coated CIPs is detected using the Fourier Transform Infrared Spectroscopy (FT-IR). The saturation magnetization (Ms) of pure and coated CIPs is 245 emu/g and 120 emu/g, respectively, at 15 kOe, which is obtained by using a superconducting quantum interface device (SQUID). The rheology flow curve properties show that MRF-1 and MRF-2 exhibit yield stress of about 10 kpa and 9 kpa, respectively, for varying magnetic fields ranging from 0 to 343 kA/m. The Herschel-Bulkley model is fitted with the experimental data and the shear thinning behaviour is observed for both MR fluids. The sedimentation study shows that MRF-2 has better settling rate than MRF-1, which is observed by using the visual observation method up to 600 h.

Although smart materials, specifically magnetorheological (MR) fluids, have shown remarkable practical importance, their drawbacks such as an aggregation of magnetic fillers, insufficient compatibility with the carrier liquid, low resistance to corrosion and poor sedimentation stability still cause severe limitations for their broader utilization. To address this challenge, our study presents a facile concept for the coating of magnetic particles, leading to their enhanced utility properties and sufficient MR performance. This concentrates on the coating of magnetic carbonyl iron (CI) particles with a thin modifying layer as a surface shell utilizing four organosilanes; tetraethoxysilane, (3-aminopropyl)triethoxysilane, bis[3(trimethoxysilyl)propyl]amine and vinyltrimethoxysilane. Characterization of the modified particles and their suspensions was examined using various methods. XPS analysis confirmed the successful particle modification, while the surface free energy was evaluated by tensiometric measurements reflecting the better compatibility of particles with the dispersing medium. The lowest surface free energy possessed particles modified with (3-aminopropyl)triethoxysilane. The magnetization of the modified core-shell particles was not negatively affected by the organosilanes layer present on the particles resulting in comparable MR performance of the systems based on pure CI particles and their modified analogues as was proved by the fitting of the corresponding flow curves by the Robertson-Stiff model. Moreover, the modification of the particles improved their thermo-oxidation stability and chemical stability investigated via thermogravimetric analysis and acidic tests, respectively. Finally, the sedimentation stability of the modified particle-based systems expressed as a weight gain measured using a tensiometer device was enhanced in comparison with the pure CI particle-based system, which can be very positive in the intended applications.

With the development of mould manufacturing industry, the high precision polishing technologies of Ni–P-coated SKD11 steel are in high demand. In this work, the factors influencing the magnetic material polishing process were determined by investigating the force distribution of carbonyl iron (CIPs) and abrasive particles (APs) in the working surface of magnetorheological fluid (MRF). The influence of certain factors, such as the diameters of the CIPs and the APs and the current and working distance (K), on the polishing surface quality, was assessed by fuzzy grey and Taguchi analysis. Results showed that the values of the fuzzy grey relationships with the surface quality of the factors were 0.4914, 0.7797, 0.6686 and 0.7461. Result showed that the fuzzy grey relationship point of factors known as diameters of the AGs had the most remarkable influence on the polishing effect, and the effect of CIP diameter was insignificant. The MRF contained commercially available CIPs that had been successfully applied for polishing the surface of magnetic materials with extremely high accuracy (surface roughness Ra = 0.561 nm) without leaving scratches on the surface after polishing.

Rod-like magnetite/sepiolite nanocomposite particles were fabricated using a chemical co-precipitation process and introduced as an added ingredient in a carbonyl iron (CI)-based magnetorhological fluid (MRF). The morphologies of the composite particles and CI-magnetite/sepiolite mixture were observed by scanning electron microscopy. Two types of MRFs with and without magnetite/sepiolite additive were fabricated, and their MR behaviors and sedimentation stability were investigated using a rotation rheometer and an optical analyzer system of Turbiscan, respectively. The results showed that the addition of rod-like magnetite/sepiolite additives enhanced both the dispersion and MR properties of CI-based MRF, making its potential application more promising.

This study deals with the development of a printable composite material based on a polyphenylene sulfide (PPS) matrix and carbonyl iron (Fe) particles, with controlled electromagnetic performance. More specifically, materials were simultaneous melt mixed and shaped under the form of filament with a diameter suitable for Fused Deposition Modeling. After reminding the potentialities of the printable PPS matrix, especially in terms of temperature resistance, microwave characterizations were performed on toroidal samples. The measured electromagnetic properties were compatible with absorption applications and compared to those of a commercial iron-filled PolyLactic Acid (PLA). Rectangular waveguide microwave loads were designed and fabricated by Fused Deposition Modeling with both materials. The PPS-Fe load has a volume that is 7 times lower than the PLA-Fe load due to a higher permittivity-permeability product and losses. Heat treatments demonstrated that no degradation is observed for the PPS-Fe load up to 180 ℃ while the PLA-Fe load is totally melted at 150 ℃. In the same time, it was observed that the maximum power supported by the PPS-Fe load is three times higher than the one supported by the PLA-Fe load. Finally, the temperature stability of the electromagnetic response of the PPS-Fe composite was demonstrated by measurements in the −70 ℃ to 140 ℃ temperature range. This new high temperature printable composite paves the way to the development of efficient, low-cost, low-weight, power and temperature stable absorbers for microwave applications.

In this study, magnetizable polyurethane sponges (MSs) were obtained from commercial absorbent polyurethane sponges (PSs) doped with carbonyl iron microparticles (CIPs). Based on MSs, we manufactured cylindrical capacitors (CCs). The CCs were subjected to both a magnetic field and an alternating electric field, with a frequency of f=1 kHz. Using an RLC bridge, we measured the series electric capacitance, Cs, and the tangent of the loss angle, Ds. From the functions Cs=Cs(δ)CCs and Ds=Ds(δ)CCs, we extracted the components of the complex dielectric permittivity. It was found that the CIPs embedded in the MS matrix aggregated, leading to magneto-dielectric effects such as the enhancement of the complex dielectric permittivity components when applying the magnetic field as a principal effect and the enhancement of the electric capacitance and time constant of the capacitors as a secondary effect. The obtained results represent landmarks in the realization of low-cost magnetic field sensors, deformation and mechanical stress transducers in the robotics industry, etc.

To investigate Haematinic definitions accessible in India arcade for their assortments of measurements structures, hard salts utilized, the substance of essential iron, recurrence of organization compulsory, the occurrence of extra supplements, levelheadedness and price. Haematinic details recorded in IDR 2018, were investigated for salts of Iron present. Arrangements of ferrous fumarate were additionally investigated for Iron substance, presence of folic corrosive and other included extra parts. A sum of 522 plans, 291 (55.74%) was oral strong measurement structure, 206 (39.46%) were oral fluids and 25 (4.7%) were parenteral. Iron salts in these details were in a type of ferrous fumarate, carbonyl iron, iron ascorbate, iron ammonium citrate, ferric hydroxide polymaltose perplexing, ferrous sulfate, sodium hydrate. Carbonyl iron was available in 92 arrangements and was most ordinarily utilized readiness in oral strong plans. A few details moreover contained Vitamin B12, zinc sulfate, histidine, lysine different multivitamins and calcium arrangements in factor extent. Out of 291 oral strong, 45 (15.46 %) arrangements required organization > three times each day to accomplish the remedial fixation. The normal expense of the sound planning was more than the normal expense of silly arrangement. Investigation of different haematinics shows there is no consistency in details. Iron and folic corrosive are included wide factor range in addition, different substances were additionally included with no very much demonstrated proof. Steps ought to be taken to normalize these details.

To analyze the effect of magnetite Fe3O4 disk-shaped nanoparticles with flake-shaped microparticles in water-based magneto rheological (MR) suspension, the rheological properties were studied using a parallel plate rheometer. The morphology, crystallinity, and magnetic property of the prepared MR suspensions were examined by field emission scanning electron microscopy (FESEM), X-ray diffraction, and vibrating sample magnetometer, respectively. In the presence of a magnetic field, micron-sized carbonyl iron (CI) particles lead to form a robust columnar structure with Fe3O4 nanoparticles and enhanced the magnetorheological performances. The magnetorheological performances of MR suspensions were examined in shear rate, shear strain, and shear stress testing sweep modes with and without a magnetic field. It was observed that adding the 1 wt% of Fe3O4, the magnetorheological performance of MR suspension enhanced. The MR fluid with CI/Fe3O4 nanoparticle mixture showed significantly higher shear viscosity and shear stress and yielded stresses than pure CI-based MR fluid. The yield stresses were higher in the shear rate sweep mode than strain and stress sweep testing modes.

A high-performance soft-magnetic composite (SMC) has been successfully fabricated in a toroidal mold without the application of compaction pressure by mixing three different alumina-coated Fe-based metal powders, namely carbonyl iron (FM), Fe-Si-Cr alloy (FSC), and Fe-Si-Al alloy (sendust), with epoxy resin in a centrifugal paste mixer. Surface coating with an alumina layer was performed via a sol–gel process, and its thickness was controlled by varying the coating time. Without the alumina coating, the SMC toroidal core with a FM:FSC:sendust mixing ratio of 8:22:70 by mass exhibited optimal magnetic properties including an effective permeability (μeff) of 33.9 and total core loss (Pt) of 252 mW/cm3 at 100 kHz with an amplitude (B) of 50 mT. With the alumina coating, however, the SMC toroidal core with the same mixing ratio exhibited a significantly reduced Pt value of 213 mW/cm3 while its μeff value was slightly decreased to 32.4, primarily due to the suppression of the macroscopic eddy-current loss from 115 mW/cm3 to 85 mW/cm3. These results indicate that an optimal mixture of the three different alumina-coated Fe-based metal powders is very effective for fabricating high-performance SMC cores without external pressure for molding, being applicable for miniature electronic components.

Oriented flaky carbonyl iron and MoS2/polyurethane (FCI & MoS2/PU) composite with wide absorption bandwidth at thin thickness was successfully prepared by shear force. The morphology, electromagnetic, and microwave absorption properties in the frequency of 2.6–18 GHz of the composites were investigated. It was observed that the flaky FCI and MoS2 particles became orienting along the tape-casting direction under shear force and parallel to each other. Compared with the un-oriented FCI & MoS2/PU composite, the higher complex permittivity and permeability were obtained after oriented, which was superior in achieving improved microwave absorption performance at thin thickness. Wider absorption bandwidths of reflection loss (RL) values below − 5 dB were obtained at the thin thicknesses of 0.5–1.2 mm for the oriented FCI & MoS2/PU composite. It suggests that the orientation by shear force is a promising approach for the preparation of materials with good microwave absorption property at thin thickness.

Existing methods for electromagnetic interference suppression typically employ attaching absorbers to the external surface of a structure at a fixed distance. In this work, we present a dynamically...

Efficacy and outcome of all magnetorheological finishing (MRF) processes depend on rheological properties of the magnetorheological (MR) fluid which consists of carbonyl iron particles (CIPs), abra...

Spherical carbonyl iron (Fe) powders were coated with magnesioferrite (MgFe2O4) insulating coating layer and then mixed with epoxy-modified silicone resin (ESR). Soft magnetic composites (SMCs) were fabricated by compaction of the coated powders and annealing treatment. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS) revealed that the MgFe2O4 layer was coated on the surface of the iron powders. The magnetic properties of SMCs were determined using a vibrating sample magnetometer and an auto testing system for magnetic materials. The results showed that the SMCs prepared at 800 MPa and 550 °C exhibited a significant core loss of 167.5 W/kg at 100 kHz and 50 mT.

Impedance matching and enhanced microwave attenuation have been proven to be effective strategies for improving reflection loss (RL) and widening of the effective absorption (RL

In the present study, development of a novel oriented polymeric composite comprising of Polycaprolactone (PCL) polymer and carbonyl iron filler particles (CIP) is presented. Incorporation of permanent magnets into solvent based extrusion 3 D printing set up produced the oriented polymeric composites. The microwave absorption properties of the oriented composite were investigated and compared with non-oriented composite and pristine PCL by utilizing vector network analyzer (VNA) and Nicolson-Ross-Weir (NRW) methodology. Higher values of permeability, permittivity, dielectric loss and magnetic loss of the oriented composite indicated the micro capacitor behaviour and domain wall motion of the parallel aligned CIP chains in the PCL matrix. The reflection and transmission loss values for the oriented composite were found to be -34 dB and -26 dB respectively. The microwave absorption of the oriented PCL/CIP composite was found to be approximately 93% suggesting the efficacy of the 3 D printed oriented composite as an excellent microwave absorber.

High-energy ball milling is a very common method to produce materials with high magnetic permeability due to its ability to produce flaky shape particles on the nano-scale. It is an efficient technique to improve microwave absorbing properties. Therefore, this study aims to achieve an ideal microstructure and improve microwave absorption properties of flake carbonyl iron powder fabricated by high-energy ball milling. The influence of pre-heating at different times/temperatures on magnetic absorbing properties is also investigated. Further, the relationship between heat treatment temperature, permeability is analyzed. Microstructural analyses reveal that the phase of the material does not change with the change of pre-heating temperature. However, the material made by ball-milling has a finer grain size and a higher flattening ratio. The results show that the length to diameter ratio of the flake material can be increased by pre-heating, and thus improve the magnetic permeability and absorbing performance of the material. The optimal parameters of pre-heating are obtained at the temperature and time of 200 °C and 2 h, respectively, wherein the real part of the permeability reaches up to 3.20 at 2 GHz, the imaginary part reaches 1.61 at 6.2 GHz.

For the aspheric optical surface finished with a doughnut-shaped MCF (magnetic compound fluid) polishing tool, the performance of the polishing tool depends mainly on the properties of the MCF slurry. Therefore, understanding the effect of each MCF slurry component on the polishing characteristics is crucial to developing novel polishing techniques. In this paper, the polishing principle was depicted and the corresponding polishing jig was constructed with a six-degree-of-freedom manipulator. The conical surfaces, which were considered as special aspheric surfaces, were experimentally polished under proper polishing conditions to examine the effects of the carbonyl iron particles (CIPs) concentration and the sizes of the abrasive particles (APs) on the polishing ability to remove material/tool marks and improve work surface qualities. Theoretical analyses were also performed to gain a more comprehensive understanding of the behaviors of CIPs and APs in the magnetic field. The results were shown as follows: (1) The CIPs concentration affected positively the magnetization of the MCF slurry, leading to better performance in the removal rate of material/tool marks when a higher CIPs concentration of was applied. The best surface quality was attained with a CIPs concentration of 45 wt%. (2) Larger APs were beneficial for obtaining higher removal rates of material/tool marks. The APs with 1 μm in diameter were preferred for achieving a better surface quality. (3) Ferric clusters were formed along the magnetic line of force and their orientations changed periodically to stir the APs with the magnet revolution. (4) The Aps, at a given working gap, can squeeze the work-surface. The squeezing action was much more intense when larger APs and the MCF slurry with a higher magnetization were employed. (5) The material removal model suggested that the material was removed due to the APs and the relative motion between the work-surface and APs.

The use of magnetic abrasive machining in the production of components for gas-turbine airplane engines is considered. The abrasive machining of a titanium alloy, high-speed steel, and a hard WC–Co alloy by means of a suspension of diamond powder and carbonyl iron particles in a hydrocarbon liquid is analyzed.

Gelatin-based systems have great potential in bio-medical applications. Here, we report the solvent uptake and DC conductivity of glutaraldehyde-crosslinked gelatin hydrogels and ferrogels. Both the parameters are found to depend on cross-linker (glutaraldehyde) and dopant (carbonyl iron) concentrations. Higher cross-linker proportions cause decrease in solvent uptake, equilibrium swelling ratio and DC conductivity. Solvent uptake is seen to increase while equilibrium swelling ratio and DC conductivity decrease with dopant concentration in the ferrogels. The solvent uptake and DC conductivity behaviour of the studied systems are explained on the basis of variations in pore size and polymer segmental mobility which, themselves, are functions of cross-linker and dopant concentrations. The diffusion process in the hydrogels and ferrogels obeys the second-order kinetic model.

Iron coated carbon nanotube (CNT) nanocomposite absorbents were prepared by a metal organic chemical vapor deposition method using carbonyl iron as the Fe precursor. The microstructures and electromagnetic properties of the composites were characterized by XRD, FESEM, TEM, and a vector network analyzer. Results show that the morphology and microwave absorption properties of these core-shell composites are controlled by changing the deposition temperature. The number of iron nanoparticles deposited on the surface of the CNTs gradually increases with increasing deposition temperature in the range 210–240 oC. Too high a temperature (270 oC) causes agglomeration of the Fe nanoparticles on the surface of the CNTs. When the thickness of the electromagnetic coating is 2.9 mm, the composite prepared at 240 oC has the best microwave absorption, with a maximum absorption bandwidth of 6.1 GHz (10.2-16.3 GHz), a minimum reflectivity of −28.3 dB and an absorption intensity less than −10 dB at 6.1 GHz.

The available magnetic field assisted finishing process is considered as the critical stage for improvement of workpiece surface quality. This paper aims to investigate the key quality performance of an enhanced magnetic abrasive finishing in achieving nanolevel finish on Ti–6Al–4V workpieces with initial micrometer surface roughness values. The finishing media, combining the intelligent shear thickening fluids (STFs), carbonyl iron particles and SiC particles, is developed. Finishing experiments for Ti–6Al–4V workpieces are conducted using an established platform, aiming to investigate the effects of varying STFs concentration, working gap, feed rate and spindle rotational speed. It is observed from the experimental results that the developed finishing media is effective for surface finishing comparing to the finishing media without STFs. The surface roughness of 54 nm was achieved from the initial value of 1.17 μm, which improved by over 95%, under the experimental conditions of 0.8 mm working gap, 15000 mm/min feed rate, 900 rpm spindle rotational speed and 15 wt% STFs. Surface observations showed that a smooth surface without obvious scratches was obtained.

The vulcanization time of the natural rubber–based magnetorheological elastomers and natural rubber was tested by the rotor-less vulcanizer. Result shows that the magnetorheological properties were best after adding 190 copies of carbonyl iron powder. From the test of rotor-less vulcanizer and equilibrium swelling method, it could be found that, after adding 190 copies of carbonyl iron powder, the crosslink density was increased by 11% and the vulcanization time was shortened by 20%. The catalytic activity of accelerator mainly originated from its ability of forming active vulcanizing agent with sulfur atom, and the possible mechanisms had been given. The carbonyl iron powder in magnetorheological elastomers improved the magnetorheological properties and the efficiency of vulcanization.

We present a simulation of the effective electromagnetic (EM) parameters of a carbonyl iron (CI) powder - polyurethane (PU) composite based on a realistic micrometer-level 3-dimensional model by fractions. CI particles, 10 × 10 × 10, were randomly modeled in a PU matrix, and the optimized meshing condition was adapted to simulation. The calculated effective complex permittivity and permeability were compared with the classical mixing formulas and measurements of prepared CI-PU samples to verify the simulation results. Studies of the local EM field distribution and a parametric analysis of the composite revealed how the randomly distributed particles behaved differently than periodic particles. This study shows the possibility of designing a composite material based on a full-wave simulation.

We report the microscopic, magnetic and rheological properties of magnetorheological elastomers (MRE) with carbonyl iron magnetic particles (CIP) dispersed into silicone in the concentration range 5–30% volume content. The samples have been fabricated under the action of a magnetic field (anisotropic A-MRE) or without it (isotropic I-MRE). For the A-MRE samples and at low particle concentration, the anisotropy is evident in the microstructure and the magnetic properties. However and at high particle concentration, the microstructural and magnetic anisotropy is much less noticeable and makes difficult to distinguish between isotropic and anisotropic state. The rheological characterization shows changes in the storage modulus G′ when CIP content is from 5 to 30% volume and I-MRE (72% change) and A-MRE (70% change) character of the samples. However, this influence is remarkable in the loss modulus G″ with big changes when considering CIP content from 5 to 30% volume and I-MRE (114% change) and A-MRE (142% change). We have also determined that the anisotropic samples with high particle content present the maximum magnetorheological effect of about 31% at low frequency (1–2 Hz).

In the present work, a solvent-based extrusion 3D printing technique has been utilized to fabricate polymer composites comprising of polycaprolactone (PCL) polymer and carbonyl iron particles. A homogenous composite ink containing PCL and carbonyl iron filler particles with suitable solvent was synthesized with required viscosity for the 3D printing operation. Rectangular samples were successfully fabricated using the extrusion 3D printing technology. A response surface methodology was utilized for planning the set of fabrication experiments so as to estimate the effect of process parameters, namely infill density, printing speed and filler concentration on the printed composite density, percentage of shrinkage and compressive strength. Shrinkage was found to reduce with an increase in infill density and filler concentration. However, density was found to shoot up with an increase in infill density and filler concentration. Similarly, compressive yield strength was improved with an increase in infill density and filler concentration. Increase in shrinkage and density values and decrease in compressive yield strength value were noticed with an increase in the printing speed. Furthermore, a genetic algorithm multiobjective optimization tool was utilized to obtain optimum process parameters to minimize shrinkage, minimize density and maximize compressive yield strength for the electronics and microwave applications of the fabricated composite. A microwave shielding performance test of the developed composite was also carried out as a case study. The shielding performance test indicated the efficacy of the polymer composite fabricated using solvent-based extrusion 3D printing technique.

In order to prepare magnetorheological fluid with excellent sedimentation stability, various surfactants are applied to coat carbonyl iron powder. The prepared magnetorheological fluid shows excell...