Iron Powder Content Research Articles

Experimental Study on Proportion Optimization of Rock-like Materials Based on Genetic Algorithm Inversion.

It is very important to clarify the optimization method of the rock-like material ratio for accurately characterizing mechanical properties similar to the original rock. In order to explore the optimal ratio of rock-like materials in gneissic granite, the water-paste ratio, iron powder content and coarse sand content were selected as the influencing factors of the ratio. An orthogonal test design and sensitivity analysis of variance were used to obtain the significant influencing factors of the ratio factors on seven macroscopic mechanical parameters, including compressive strength σc, tensile strength σt, shear strength τf, elastic modulus E, Poisson's ratio ν, internal friction angle φ and cohesion c. A multivariate linear regression equation was constructed to obtain the quantitative relationship between the significant ratio factors and the macroscopic mechanical parameters. Finally, a rock-like material ratio optimization program based on genetic algorithm inversion was written. The results show that the water-paste ratio had extremely significant effects on σc, σt, τf, E, ν and c. The iron powder content had a highly significant effect on σc, σt, τf and c, and it had a significant effect on ν and φ. Coarse sand content had a significant effect on σc, E and c. The multiple linear regression model has good reliability after testing, which can provide theoretical support for predicting the macroscopic mechanical parameters of rock-like materials to a certain extent. After testing, the ratio optimization program works well. When the water-paste ratio is 0.5325, the iron powder content is 3.975% and the coarse sand content is 15.967%, it is the optimal ratio of rock-like materials.

EFFECT OF FILLER CONTENT AND SIZE ON THE FLEXURAL STRENGTH AND HARDNESS OF PURE IRON POWDER FILLED LAMINATED FIBERGLASS EPOXY COMPOSITES

The aim of this work is to evaluate the effect of the amount of pure iron powder (99.9987%), introduced as a filler in a glass-epoxy composite laminate, as well as the variation of its grain dimensions, on its flexure strength and hardness. Contact molding was used to produce laminate plates of 15, 20, and 25% of weight content with three different dimensions 92, 64, and 32 μm, and the fiberglass content was set at 30%. For the bending test, the specimens were prepared according to ISO 14125 standard specification, the test was carried out with three different speeds, and the required number of specimens were manufactured according to Taguchi's orthogonal array L9 (3 × 3) by varying three parameters (iron powder content, grain size, and test speed). The results were studied with the Taguchi method; however, the hardness was measured on plates with the same iron powder content while varying the dimensions of its grains (92, 64, and 32 μm). The results show that the pure iron powder content and dimension variations have a direct and clear influence on the composite material's mechanical characteristics, in such a way that: a specific percentage of filler and grains size reduction could widely increase the hardness as well as the material flexure strength. The results of the elaborated composite material's bending test were compared to a 45% glass-epoxy laminate. Whereas the hardness of the elaborated laminate was compared to a resin plate and the 45% glass-epoxy laminate.

Influence of iron powder content on the electromagnetic and mechanical performance of soft magnetic geopolymer composite

In the induction heating of airport pavement to remove snow and ice, soft magnetic geopolymer composite (SMGC) can be used to gather the dissipated electromagnetic energy, thus enhancing the energy utilization efficiency. The aim of this work is to analyze the influence mechanism of iron powder content on the electromagnetic and mechanical performance of SMGC, so as to provide theoretical guidance for the design of soft magnetic layer within airport pavement structure. The results show that the increase of iron powder content reduces the resistance and magnetoresistance of SMGC by decreasing the content of non-magnetic phases between iron powder. However, the reduction of iron powder spacing also provides a shorter transmission path for the inter-particle eddy currents in the SMGC specimen, which enhances the exchange coupling between iron powder, thus increasing the electromagnetic loss. Therefore, the compatibility between magnetic permeability and electromagnetic loss should be considered comprehensively in the mix design of SMGC. In addition, although iron powder can enhance the mechanical properties of SMGC by improving the density of geopolymer matrix, the excessive amount of iron powder can lead to a weak interfacial transition zone between geopolymer matrix and iron powder. According to the induction heating results, optimized SMGC can improve the energy transfer efficiency of induction heating by 24.03%.

Process optimization and mechanism of high-efficiency germanium extracting from zinc oxide dust containing germanium enhanced by ultrasound

Aiming at the problem of low extraction efficiency of germanium in zinc oxide dust, a process of strengthening germanium leaching by ultrasonic wave in sulfuric acid leaching process was proposed. The effects of acidity, temperature, time, liquid-solid ratio, ultrasonic power and amount of iron powder on germanium leaching were investigated by response surface method, and the ultrasonic enhanced leaching process was optimized. Based on process mineralogy analysis, and germanium phase distribution analysis, which is obtained by self-establishment step-by-step extract method, the studied zinc oxide dust contains 94.1% germanium oxide and germanate, 5.13% germanium sulfide and 0.77% insoluble germanium. The results showed sulfuric acid concentration 131 g/L(1.34 mol/L), temperature 78 °C, time 22 min, liquid-solid ratio 7.6:1, ultrasonic power 270 W, iron powder content 0.71%. The leaching efficiency of germanium is 95.19%, which is 5.79% higher than that of conventional leaching method. It was found that ultrasound can destroy the particle size, reduce the cluster structure of leached products by 13.5%, inhibit the agglomeration of particles, and promote the leaching of germanate and germanium sulphide. This study is of great significance for the production of germanium.

Effect of iron powder content on microstructure and mechanical properties of Al2O3p/high manganese steel composites prepared by casting infiltration

Al2O3p/high-manganese steel-matrix composites were successfully fabricated by gravity casting infiltration, with iron powder added in the preforms to adjust the Al2O3p fraction. The effects of the iron powder content (38, 48, and 55 wt%) on the microstructures and mechanical properties of the composites were investigated. With the increase in the iron powder content in the preform, the Al2O3p fraction decreased (57–38 vol%), while the hardness and compressive strength of the composite gradually increased. The highest compressive strength was 1000.3 MPa (55-wt% iron powder). The highest work hardening rate (55-wt% iron powder) well reflected the synergistic effect between the matrix and reinforcement to prevent dislocation movement. The water glass binder formed thick interface layers between Al2O3p and matrix, which transformed the Al2O3/metal interface bonding from mechanical bonding to metallurgical bonding. A too thick interface layer deteriorated the mechanical properties of the composites.

Microwave absorption properties of cementitious composites containing carbonyl iron powder (CIP) and fly ash: Formation and effect of CIP core–shell structure

The superior microwave absorption of cementitious composites is beneficial for reducing buildings’ microwave pollution. This study prepared cementitious composites and characterized their microwave absorption, electromagnetic properties, hydration products, and microstructures. The results confirmed that carbonyl iron powder (CIP)–calcium particles with a core–shell structure formed during the hydration of the composites without fly ash. The core–shell structure could suppress the skin effect and the dielectric loss of the cementitious composites, enhancing their impedance matching and microwave absorption. The formation of the calcium compound shell resulted in the relative lack of calcium during the hydration and enhanced the polymerization of C(-A)-S-H gels in the samples without fly ash. Increasing the carbonyl iron powder content of the composites containing high-volume fly ash improved the Debye relaxation processes and the conductivity due to a lack of a shell structure around the CIP, which enhanced their dielectric loss and magnetic loss.

Effect of type and content of iron powder on the formation of oxidized film and tribological properties of Cu-matrix composites

This paper studied the effects of iron powder types and contents on the friction and wear properties of copper matrix composites for breaking of high-speed trains. The mechanical properties, microstructure, interface, tribofilm, elements and microhardness of samples were analyzed by hardness tester, SEM, EDS and nanoindentation tests. The braking performances were measured by a tribometer mimicking the braking conditions. The results show that the wettability and combination between ferrophosphorus and matrix is poor and carbonyl iron is more suitable for strengthening matrix. The friction coefficient is most stable and the wear rate is also relatively low with 10% carbonyl iron. The increase of carbonyl iron content will promote oxidation and be conducive to the formation of friction film. The oxide degree of friction film increases in the direction from the matrix to the surface. However, too much iron powder produces excessive iron oxide which makes the friction film be easy to peel off especially under high speeds.

Optimal Proportion of Similar Materials and Rockburst Tendency of White Sandstone

To explore the tendency of rockburst, a similar material ratio was optimised based on white sandstone. Quartz sand, iron powder, gypsum, cement, retarder, and a water‐reducing agent were used as the main materials. The orthogonal test design principle was used to determine the four‐factor and four‐level orthogonal test design with the quartz sand content, iron powder content, gypsum‐cement ratio, and sand particle size as the influencing factors. Uniaxial compression tests and tensile tests were conducted on similar material models. The tensile strength and elastic modulus were analysed, the significance of each influencing factor was investigated, and the test results of the similar materials were fitted. The optimal ratios of the similar materials of white sandstone were found to be quartz sand content of 36%, iron powder content of 1.9%, gypsum‐cement ratio of 1.8 : 1, and sand particle size of 2–4 mm. The physical and mechanical properties of the similar materials were consistent with those of white sandstone. The mechanical properties of the similar materials were compared with those of the original rock. By judging the rockburst propensity and verifying the index, it is concluded that the similar materials can effectively simulate the characteristics of white sandstone, which is an ideal similar material of rockburst, and they all show strong rockburst propensity. The rock specimens with optimal proportions were produced, and the internal energy changes and rockburst mechanisms of the model at different temperatures were discussed. The results show that the rockburst process is closely related to energy, such as thermal energy and elastic strain energy, and the rock failure process can be divided into three main stages: energy accumulation, microcrack formation and propagation, and crack penetration and bursting. It provides an experimental basis for the preparation of rockburst similar materials that are more in line with the actual situation of the project and provides a basis for discussing the energy criterion of rockburst.

Effects of iron powder on properties of geopolymers subjected to different curing regimes

Silica fume, slag and iron powder are by-products from various industries. In parallel with development of industrial technology, it is also known that these by-products which cause rapid pollution of the environment are also harmful to human health because they are easily respirable. For this reason, a series of experiments were carried out to determine physical and mechanical properties on samples prepared using different blend designs to examine the effect of factors such as curing conditions, binder type and waste iron powder content. Percentages of iron powder added to replace the aggregate are 10%, 20%, 30% and 40% by volume of slag aggregate. It was observed that the substitution of 30% by volume iron powder instead of slag in geopolymer mortars is the most effective in increasing splitting tensile strength. For 40% partial replacement of fine aggregates with iron powder, increases in compressive strength and flexural strength of slag-based mortars were 7.2% and 43.4%, respectively, compared to mortar without iron powder at 60°C curing conditions.

Dynamic compressive behavior of metallic particulate-reinforced cementitious composites: SHPB experiments and numerical simulations

An experimental and numerical evaluation on the dynamic compressive response of mortars containing up to 20% waste iron powder as sand replacement is presented in this paper. The dynamic response is evaluated using split Hopkinson pressure bar (SHPB) apparatus under high strain rates (up to 250/s). The elongated iron particulates present in the iron powder-incorporated mortars warrant significantly improved compressive strength and energy absorption capacity at high strain rates. Multiscale numerical simulations are performed with a view to develop a tool that facilitates microstructure-guided design of these particulate-reinforced mortars for efficient dynamic performance. The dynamic compressive response of particulate-reinforced mortars is simulated adopting a numerical approach that incorporates strain rate-dependent damage in a continuum micromechanics framework. The simulated dynamic compressive strengths and energy absorption capacities for mortars with various iron powder content exhibit good correlation with the experimental observations thereby validating the efficacy of the simulation approach.

The response force and rate of magneto-rheological elastomers with different fillers and magnetic fields

This study looks at the response rate and magnitude of magneto-rheological elastomers (MREs) upon applying magnetic field depending on the type and content of iron powder. Specimens were prepared under different magnitudes of an applied magnetic field during vulcanization. S1640 (carbonyl) iron powder has a round shape and small size (3–5 µm), and Fe#400 (electrolytic) has irregular shape and large size (6–11 µm). Both of these were used at up to 80 phr. In general, the specimen with S1640 has a better response force and more rapid response to an external magnetic field than the specimen with Fe#400. However, the compressive characteristics of the Fe#400 specimen with low iron powder content (40 phr) and isotropic conditions are better than those of the S1640 specimen. The experimental results show better mechanical properties and rapid response with an applied magnetic field of 1.5 T compared to 2.0 T during the specimen vulcanization. This means that the smaller iron powder can move faster when applying the magnetic field than the bigger iron powder, and the iron powder distribution influences the compressive modulus and response behaviors. Therefore, the response and force to an applied magnetic field and the durability of the MRE are better with the S1640 iron powder, and the pattern is similar to the compressive modulus.

Study on Preparation and Properties of Al<sub>2</sub>O<sub>3</sub>-Fe Based Metal Ceramics

Al2O3-Fe based metal ceramic is a functional ceramic material prepared by high temperature sintering with Al2O3 as the main component, plus iron powder (binder phase) and other additives. In this paper, the composition design of Al2O3-Fe based metal ceramic was made, and the performance of the material was tested and studied. The change of the content of iron powder also has a great influence on the compressive strength and bending strength of the Al2O3 metal ceramic. Experiments also show that the Al2O3-Fe-based cermet has good corrosion resistance. Finally, the following conclusions were obtained through the comprehensive analysis: the best test formula is No.4 sample, and its compressive strength is 79.79MPa, bending strength is 15.90 MPa, corrosion resistance rate is 0.028 g/dm2·h.

Application of Molten Salt Method in Hercynite Composite Powder Synthesis at Elevated Temperature

With molten salt method, a series of the hercynite powders were prepared using FeCl2·4H2O, active alumina and iron powder as raw material and KCl molten salt as reaction medium. The phase composition and micro-morphology were studied by techniques of XRD and SEM. The results showed that a high purity hercynite-alumina powder can be synthesized by molten salt synthesis method after heat treatment at 1000 °C in reducing atmosphere, the main phases were hercynite and α-Al2O3, and the increasing iron powder content can raise hercynite production quantity with developed crystal grain, the grain size was increased from 6μm to 10μm.

Electron Beam Coatings with SHS Composite Powders “TiC - Cast Iron Binder" Synthesized in Air

The paper presents the result of studies of composite powders produced by self-propagating high temperature synthesis (SHS) in the reaction mixtures of titanium, carbon and high chrome cast iron, and electron-beam coatings based on them. It was found that the morphology and dispersion of titanium carbide particles in the SHS-product were determined by cast iron powder content in the reaction mixtures. The effect of content of the SHS powders on the characteristics of electron-beam coatings, including abrasive wear resistance of facing coatings was shown.

Crack propagation and strain localization in metallic particulate-reinforced cementitious mortars

Abstract The influence of replacing up to 30% of ordinary Portland cement (OPC) by volume with waste iron powder (containing a significant fraction of elongated particles) on the fracture response of composite mortars is reported. The increase in the overall strain energy release rate at higher particulate contents is dominated by its elastic component, which correlates well with the increase in length of the fracture process zone (FPZ), determined using digital image correlation. The tensile properties of the composites, determined from an analytical tension model, are also found to increase with iron powder content. The impact of metallic particulate incorporation was the most prominent in enhancing the tensile toughness of the composite rather than the strength or stiffness. It is shown that cementitious systems with enhanced toughness typically attained through the use of fiber reinforcement can be designed using metallic particulate reinforcement, at a much lower OPC content, which thus provides the composite with sustainability benefits also.

O Papel do Pó de Ferro no Mecanismo de Deposição de Eletrodos Revestidos

A principal motivação deste trabalho foi a procura da resposta para o dilema entre que as maiores taxas de produção de eletrodos revestidos com pó de ferro se devem às suas capacidade de trabalhar com maior corrente ou à uma maior eficiência de fusão metálica do ferro adicionado na forma de pó. Um estudo neste sentido foi feito utilizando-se três eletrodos comerciais, cuja principal distinção referia-se ao teor de pó de ferro no revestimento. Os eletrodos foram caracterizados em relação às suas dimensões, densidade e composição (via MEV-EDS) do revestimento. Utilizando-se dois níveis de corrente, foram avaliadas as taxas de fusão e deposição e a geometria do cordão na confecção de filetes na posição plana (junta em ângulo). Pelos resultados, verificou-se que, independentemente da intensidade da corrente, as taxas de fusão e deposição são maiores no sentido crescente da maior concentração de pó de ferro no revestimento. Ficou demonstrado que o mecanismo gerador de maiores taxas de deposição e fusão se deve à menor energia requerida para fundir o ferro do revestimento em forma de pó que o contido na alma metálica. A maior capacidade nominal de condução corrente proporcionada pelo eletrodo com pó de ferro é uma razão secundária.

Electromagnetic interference shielding nature of PVDF-carbonyl iron composites

Polyvinylidene fluoride-carbonyl iron powder (PVDF-CIP) composites with different carbonyl iron powder loading were developed for electromagnetic interference shielding applications in the X band. Shielding properties improved with increase in carbonyl iron powder content and uniform electromagnetic shielding effectiveness of about 20dB is obtained for PVDF-50 vol% carbonyl iron powder composite over the entire X band. The magnetic and dielectric loss tangent of the composite increased with increase in carbonyl iron content. It is found that the PVDF-CIP composites shield by absorption.

XμCT analysis of magnetic field-induced phase transitions in magnetorheological elastomers

The phase behavior of polymer solutions and composites is a complex issue and is of both technological and fundamental interest. For a better understanding of the microstructure formation in magnetorheological (MR) elastomers, x-ray micro-computed tomography (XμCT) investigations were carried out. Magnetorheological elastomers with 5% mass content of iron powder were prepared under different magnetic field strengths between 1 and 220 kA m−1. Through quantitative analysis, valuable information was obtained regarding the number, size and frequency distribution of column structures in MR elastomers, as well as the magnetic field required to force structure formation.

The Improving of the Process of the Iron, the Cast Iron and the Copper Powder Mixing

This paper presents the experimental results concerning the compacting process of some iron, cast iron and copper mixtures. In these mixtures the participation of the cast iron powder to the chemical composition of the mixtures was 5%, 10% and 15% and the participation of the copper powder was 2% and 5%. The paper emphasizes the influence of the carbon content, the cast iron hardness and the cast iron powder content on the mixtures compaction ability at different compacting pressures.

Column Experiment on Nitrate Purification with Polylactic Acid and Iron Powder

Groundwater contamination by nitrates is a worldwide problem, but to date there have been no effective measures to purify contaminated groundwater. If a denitrifying system can be constructed in aquifers, it will be able to purify groundwater in situ. This purifying system should also be maintenance free. The purpose of our work is to construct a maintenance-free denitrification system for in situ groundwater purification. This paper presents the result of a basic study on a maintenance-free denitrification system using biodegradable plastic and iron powder. A biodegradable plastic (polylactic acid, PLA) and iron powder were used as detergents, and the nitrate-contaminated groundwater was injected from the bottom of a packed silica sand column filled with a mixture of the detergents. Laboratory experiments were carried out, varying factors such as molecular weight of the biodegradable plastic and mixing ratio of the detergents. Water that permeated through the purification column was sampled to determine the decrease in nitrate concentration. The experimental results suggest that a combination of PLA and iron powder seems effective for denitrification, and that the rate of the PLA degradation is closely related to the molecular weight of the PLA and iron powder content. In this case iron powder acts as accelerator in denitrification. It is concluded that a maintenance-free denitrification system can be built, using PLA and iron powder as detergents. The proposed system may also be used in a wide range of nitrate contamination conditions, adjusting the molecular weight of the PLA and the mixing ratio of the detergents.