Different Concentrations Of Fe2O3 Research Articles

Investigating the Effect of Fe2O3 on Wear Behaviour and Corrosion Resistance of Electroless Ni–P Coating with Different Fe2O3 Concentrations on AISI 4140 Steel

In this study, Ni–P–Fe2O3 composite was deposited on AISI 4140 steel using different concentrations of Fe2O3 ranging from 0.1 to 0.5 gr/lit in an electroless bath. The phase analysis and surface morphology of the samples were characterized using X-ray diffraction and FESEM. The corrosion behavior of the coated samples was investigated in a 3.5 wt. % NaCl solution through potentiodynamic polarization. The results of the potentiodynamic test show that adding Fe2O3 into an electroless bath facilitates the formation of the passive layer. The results show that the coating created at a thickness of (10-16µm) had the highest corrosion resistance compared to other coated and non-coated samples. Furthermore, the results of the friction coefficients of the samples produced by powder metallurgy have decreased because Fe2O3 particles led to a decrease in grain size in the heat treatment of specimens and prevented excessive heat generation during the wear test; thus, the friction coefficient decreased during the test.

Dielectric Relaxation Dynamics and Polaronic Tunneling Conduction Mechanism of Electrical Conductivity of Fe2O3‐Doped PbO–ZrO2–SiO2 Glass Ceramics

This study consists of comprehensive investigations on dielectric permittivity (ε′), electric moduli (M′, M″), impedance (Z), and conductivity (σac) spectra over broad regions of frequency and temperature of lead zirconium silicate glass ceramics mixed with different concentrations of Fe2O3. The observed increase in dielectric permittivity with the content of Fe2O3 is attributed to the increasing presence of iron ions in octahedral positions. Electric moduli plots with frequency (ω) and temperature (T) exhibit dipolar effects. These effects are quantitatively analyzed by Cole–Cole plots; the analysis indicates the distribution of relaxation times. Probable dipoles for these effects are identified and discussed. AC conductivity (σac) shows a rising trend with an increase in Fe2O3 beyond 0.2 mol%, and this increase is attributed to the polaron exchange among Fe2+ and Fe3+ ions. The conduction mechanism is well explained using a polaron tunneling model in the middle‐frequency and high‐temperature regions.

New Materials Synthesized by Sulfuric Acid Attack Over Power Plant Fly Ash

In the current work, the preparation of a complex wastewater coagulant based on polymeric sulfates of aluminum/iron from fly ash is presented. The performance of the coagulation�flocculation process is mostly influenced by the coagulant type, which enhances the aggregation of particles and leads to formation of fast-settling flocs by charge neutralization or chain-bridging mechanisms. Within the preparation process, the reaction temperature was controlled at 80�C and 90�C for 4 h, the synthesized materials being characterized through different techniques (SEM, EDAX, FTIR, and XRD) and further used as coagulants for real wastewater treatment. As a novelty of this study, it can be mentioned that there were analyzed the possibilities of capitalization of Romanian fly ash collected from Iasi area and its transformation into complex based on aluminum - iron sulfates. Fly ash containing different concentrations of Fe2O3 and Al2O3 was successfully used in producing complex coagulants by reacting with 10% technical sulfuric acid solution. The produced complex coagulants contain both polymeric ferric sulfate (PFS) and polymeric aluminum sulfate (PAS) (demonstrated by complex characterization) and proved to be effective in wastewater treatment. These sustainable materials exhibited a good performance in coagulation�flocculation process (e.g. it was obtained a TSS removal efficiency of 84% at the coagulant dosage of 60 mg/L).

Removal of cadmium from aqueous solutions using inorganic porous nanocomposites

The present paper reports a one-pot synthesis of magnetic nanocomposites samples through acid catalyzed sol-gel method. Fe(III) acetylacetonate was used as precursor of the iron oxide phase: tetraethylortosilicate for the silica phase and polyvinyl alcohol (PVA, molecular mass 49000) as pore former. Different concentrations of Fe2O3 in composites matrices were prepared and studied ranging from 0% to 20%. All reactions took place in one pot at room temperature; the materials were subsequently heat treated at 300°C, to ensure the crystallinity for the iron oxide having spinel structure, forming nanoparticles confined in the silica matrix. The materials were characterized using X-ray diffraction, small-angle neutron scattering, FT-IR spectroscopy, nitrogen adsorption, Mossbauer spectroscopy and magnetization measurements. The maximum value of room temperature saturation magnetization of ∼54 emu/g and 0.11 kOe coercive field was achieved for the magnetic nanocomposite sample with 20% Fe2O3. The highest surface area of 680m2/g was obtained for the sample with 10% Fe2O3. The potential applicability of the obtained materials was studied for adsorption performance for cadmium in aqueous solutions. The Langmuir isotherm model described well the adsorption data, indicating monolayer adsorption of Cd(II) on the heterogeneous composite surface.

Effect of Fe2O3 and WO3 nanoparticle on steam injection recovery

ABSTRACTNanotechnology has the potential to introduce revolutionary changes in several areas of oil and gas industry. In this paper, the effect of different concentrations of Fe2O3 and WO3 nanoparticles at various temperatures was studied on viscosity of heavy oils. The effect of Fe2O3 and WO3 nanoparticles mixture on steam injection process is studied. The experimental tests show that some of these nanoparticles decrease the heavy oil viscosity to less than 40% in certain concentration at different temperatures. Our results of steam injection tests show that the injection of Fe2O3 and WO3 nanoparticles mixture increases the heavy oil recovery.

Assessment of role of iron ions on the physical and spectroscopic properties of multi-component Na2O−PbO−Bi2O3−SiO2 glass ceramics

ABSTRACTMulti-component glass ceramics composition Na2O−PbO−Bi2O3−SiO2 doped with different concentrations of Fe2O3 as nucleating agent were characterised by XRD, SEM (scanning electron microscope) and DTA (differential thermal analysis) techniques. Optical absorption, EPR, FTIR and Raman studies are also carried out on these glass ceramics. Absorption bands observed at about 457, 489, 678 and 820 nm are the characteristics of Fe3+ ions whereas the band observed at about 964 nm is due to Fe2+ ions. EPR studies suggested that Fe3+ ions entered in the lattice as tetragonally distorted octahedral symmetry or rhombic sites at low concentration of Fe2O3, whereas at higher concentration of Fe2O3 (beyond 1 mol%), the super exchange type of interactions between multivalency iron ions begin to dominate. FTIR and Raman spectra have revealed the behaviour of various structural units in the glass ceramic matrix. The analysis of these spectroscopic studies indicates that iron ions do exist in Fe3+ and Fe2+ state.

Development of Novel Drilling-Fluid Nanoparticles for Enhanced Drilling Operations

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 18381, “Development and Testing of Novel Drilling Fluids Using Fe2O3 and SiO2 Nanoparticles for Enhanced-Drilling Operations,” by Zisis Vryzas, Texas A&M University at Qatar; Omar Mahmoud and Hisham A. Nasr-El-Din, Texas A&M University; and Vassilios C. Kelessidis, Texas A&M University at Qatar, prepared for the 2015 International Petroleum Technology Conference, Doha, Qatar, 7–9 December. The paper has not been peer reviewed. Copyright 2015 International Petroleum Technology Conference. Reproduced by permission. This work focuses on the laboratory techniques for developing, assessing, and analyzing innovative water-based drilling fluids containing iron oxide (Fe2O3) and silica (SiO2) nanoparticles. The examined nanoparticles have the potential to significantly improve the characteristics of the filter cakes at both low-pressure/low-temperature (LP/LT) and high-pressure/high-temperature (HP/HT) conditions. They also have the ability to maintain optimal rheological properties so that many drilling problems can be mitigated efficiently. Introduction Drilling-fluid loss is considered the major source of capital expenditure during drilling operations. Nanoparticles have proved to be more effective in reducing the filtrate losses than conventional fluid-loss reducers. Because they exhibit different adsorption and transportation behavior in different porous media, nanoparticles have been used successfully as stabilizers in emulsions and foams, as rheology modifiers, and as fluid-loss additives in surfactant/polymer or water-based drilling fluids. Addition of Fe2O3 and SiO2 nanoparticles can improve or at least maintain fluid properties even at high temperatures. This work aims to find the optimal concentration of such nanoparticles. Experimental Procedure Materials and Sample Preparation. Bentonite was supplied in powder form; the water/bentonite suspension gives a mixture with a pH range of 8 to 10. The Fe2O3 nanoparticles were purchased in powder form with a spherical shape and an average diameter of less than 50 nm with a purity greater than 97%. Nanosilica was purchased in powder form with a spherical shape and an average diameter of 12 nm with a purity greater than 99.5%. Deionized water with pH range 6.8 to 7.2 was used along with the bentonite to prepare the base fluid. All the prepared samples had pH in the range of 7.9 to 8.3. The preparation of the samples was carried out following American Petroleum Institute (API) standards. The base fluid (BF) was formulated with a bentonite concentration of 7.0 wt% in 600 cm3 of deionized water. Different concentrations of Fe2O3 and SiO2 nanoparticles were used (0.5, 1.5, and 2.5 wt%). First, bentonite was added to deionized water and mixed for 20 minutes. The desired concentration of nanoparticles was added slowly to minimize the agglomeration, and mixing continued for 20 more minutes. The samples were then sealed in plastic containers and left for 16 hours at room temperature for the bentonite to hydrate.

High strength and toughness in chromatic polymer-infiltrated zirconia ceramics

ObjectiveTo evaluate the microstructure and mechanical behavior of polymer-infiltrated zirconia ceramics as a function of Fe2O3 concentration (0–0.3mol%). MethodsPolymer-infiltrated zirconia ceramics with different concentrations of Fe2O3 were prepared by infiltration and polymerization. XRD was employed to determine phase structure. The microstructure and fracture mechanism was observed by SEM. Flexural strength and fracture toughness were measured by three-point bending method and single-edge-notched beam method, respectively. Data were analyzed by Weibull distribution. A nanoindentation system was employed to determine elastic modulus and hardness. ResultsWith increasing content of Fe2O3, the flexural strength, fracture toughness, elastic modulus and hardness are all greatly enhanced and the chromatic behavior also improves significantly. As a tradeoff made between strength and elastic modulus, specimen containing 0.2mol% Fe2O3 is found to be the better one, with flexural strength and fracture toughness values being 336.8MPa and 3.91MPam1/2, respectively. Moreover, it maintains a relatively low elastic modulus of 88.2GPa and a moderate hardness of 4.8GPa, close to those of natural enamel. SignificanceThis polymer-infiltrated zirconia ceramic material is a dental material of biomimetic chromatic and mechanical properties.

Structure and chemical durability of ZnO–B2O3–P2O5–R n O m glass system with Fe2O3 additive

ZnO–B2O3–P2O5–RnOm glasses containing different concentrations of Fe2O3 (ranging from 0 to 5 mol %) were prepared. A number of studies viz., glass transition temperature (Tg), density (α), thermal expansion coefficient (a), chemical durability, infrared spectroscopic and X-ray diffraction (XRD) patterns of these glasses had been carried out. The results of these studies have been analyzed in the light of different oxidation states of iron ions. The physical properties coupled with infrared spectroscopic and XRD indicates that the iron ions (when present in the concentration range, 0–2 mol %) exist mostly in trivalent state and occupy both tetrahedral and octahedral substitutional positions and are found to increase the rigidity of the glass network. However, in the concentration range of 2–5 mol %, the iron ions in the glass network seem to be existing by and large in Fe2+ state, occupying predominantly octahedral positions and are acting as modifiers.

Effect of coloration with various metal oxides on zirconia

The aim of this study was to evaluate the coloration of zirconia ceramic by adding three kinds of metal oxide. This was done with different concentrations of Fe2O3, CeO2, and Bi2O3 in tetragonal zirconia polycrystals stabilised with 3Y‐TZP powder compacted at 200 MPa using cold isostatic pressure and full sintering. X‐ray diffraction analysis was used to examine the structure of the shaded 3Y‐TZP. The chromaticity of sintered bodies was measured on a spectrophotometer. The coloration of zirconia by the three kinds of metal oxide was determined. With the addition of CeO2, the lightness of the zirconia was about 84–87, a* decreased slightly, and the colour shifted to a more yellow‐green hue. With an increasing content of Fe2O3, the chroma of the ceramic became more intense, the lightness decreased, and the colour changed to a red‐yellow hue. With an increasing concentration of Bi2O3, the colour of the materials shifted to a light saffron yellow. X‐ray diffraction spectra revealed only tetragonal phase. Results show that zirconia ceramic can be colourised using Fe2O3, CeO2, and Bi2O3.

Induced crystallization and structural aspects of PbO-As2O3 glass system doped with Fe2O3

PbO-As2O3 glasses mixed with different concentrations of Fe2O3 (ranging from 0 to 0.5mol%) were crystallized. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) techniques. Studies were extended to optical absorption, . The X-ray diffraction and scanning electron microscopic studies reveal the presence of PbFe4(As5O11)2, Fe2PbAs2O6 crystal phases. The optical absorption studies together with ESR measurements indicated the dominant presence of iron ions in the trivalent state when the concentration of nucleating agent Fe2O3 is less than 0.3mol%.

Electrical and spectroscopic properties of Fe2O3 doped Na2SO4–BaO–P2O5 glass system

Na2SO4–BaO–P2O5 glasses doped with different concentrations of Fe2O3 were prepared. The valence states of iron ions and their coordination in the glass network have been investigated using optical absorption, ESR, IR and Raman spectroscopy. Electrical and dielectric spectral features have been studied over a wide frequency range (10−2–106Hz) and within the temperature range from 303 to 523K. The ac and dc conductivities have exhibited maximal effect, whereas the activation energy for the conductivity demonstrated minimum at 1.5mol% of Fe2O3. The ac conductivity in the low temperature region is explained based on quantum mechanical tunneling (QMT) model. The analysis of the dc conductivity indicated that at T>θD/2, the small polaron hopping model is appropriate. The dispersion of real part of dielectric constant ε′(ω), and loss, tan δ, with temperature have been analyzed quantitatively on the basis of space charge and orientation polarization models.

Low temperature dielectric dispersion and electrical conductivity studies on Fe2O3 mixed lithium yttrium silicate glasses

Lithium yttrium silicate glasses mixed with different concentrations of Fe2O3 of the composition (40−x) Li2O–10Y2O3–50SiO2: x Fe2O3, with x=0.3, 0.5, 0.8, 1.0, 1.2 and 1.5 (all in mol%) were synthesized. Electrical and dielectric properties including dielectric constant, ε′(ω), loss, tan δ, ac conductivity, σac, impedance spectra as well as electric moduli, M(ω), over a wide continuous frequency range of 40Hz to 106Hz and in the low temperature range 100 to 360K were measured as a function of the concentration of Fe2O3. The dc conductivity is also evaluated in the temperature range 100 … 360K. The temperature and frequency dispersions of dielectric constant as well as dielectric loss have been analyzed using space charge polarization model. The ac and dc conductivities have exhibited increasing trend with increasing Fe2O3 content beyond 0.5mol%, whereas the activation energy for the conductivity demonstrated decreasing tendency in this dopant concentration range. Both quantum mechanical tunneling (QMT) and correlated barrier hopping models (CBH) were used for clarification of ac conductivity origin and the corresponding analysis has indicated that CBH model is more appropriate for this glass system. For the better understanding of relaxation dynamics of the electrical properties we have drawn the scaling plots for ac conductivity and also electric moduli. The plots indicated that the relaxation dynamics is independent on temperature but depends on concentration of Fe2O3. The dc conductivity is analyzed using small polaron hoping model. The increase of conductivity with the concentration of Fe2O3 beyond 0.5mol% is explained in terms of variations in the redox ratio of iron ions in the glass network. The results were further analyzed quantitatively with the support of experimental data from IR, optical absorption and ESR spectral studies. The overall analysis has indicated that Li2O–Y2O3–SiO2 glasses containing more than 0.5mol% of Fe2O3 are more suitable for achieving good electrical conductivity in these glasses.

The preparation and EPR study of nanocrystalline ZnFe2O4

Nanocrystalline zinc oxide doped with different concentrations of Fe2O3(from 5 to 50 wt.%) has been prepared by means of coprecipitation and calcination processes. Depending on the chemical composition, phases of hexagonal ZnO, and/or cubic ZnFe2O4 were identified. The mean crystallite size of the latter phase, determined using the Scherrer's formula, varied from 8 to 12 nm. The EPR spectra for six different concentrations of Fe2O3 were recorded. A symmetrical, very intense and broad EPR resonance line has been obtained for the all the samples where the intensity strongly depended on the ratio of ZnO/Fe2O3 in the samples. The resonance field slightly shifted in the direction of lower magnetic field and the integrated intensities increased with increasing concentration of magnetic nanoparticles of ZnFe2O4, where the linewidth showed an extraordinary behaviour. The dipole-dipole interaction depended essentially on the concentration of magnetic nanoparticles.

Magnetic properties of PbO–Sb2O3–As2O3 glasses containing iron ions

PbO–Sb2O3–As2O3 glasses containing different concentrations of Fe2O3 (ranging from 0 to 1mol% in steps of 0.1%) were prepared. Optical absorption, magnetic susceptibility and ESR spectral studies on these glasses have been carried out as a function of Fe2O3 concentration. The interesting changes observed in these properties are discussed in the light of various oxidation states of iron ions.