Fe Dendrites Research Articles

Investigation on the dual-phase co-deformation behavior and strengthening mechanism in cold-drawn Cu–20Fe alloy

In this work, cold drawing deformation was applied aiming to achieve a good combination of strength and electrical conductivity of Cu–20Fe alloy, and also such underlying mechanisms for microstructure evolution and strengthening, as well as variation in conductivity were clarified. It is also found that both Cu matrix grains and Fe-rich dendrites can be significantly refined and transformed into fibrous structure with increasing of drawing strain. The average size of Cu grains and thickness of Fe fiber are 0.47 ± 0.05 μm and 25 ± 5 nm, respectively for alloy subjected to the drawing strain of η = 5.78. In addition, the Fe dendrites exhibit a strong <110> fiber texture, while the corresponding Cu matrix forms a <111> fiber texture. It is demonstrated that the excellent properties with the yield strength of 1173 MPa and the electrical conductivity of 41 %IACS can be reached for cold-drawn Cu–20Fe alloy. In addition, the quantitative analysis on strengthening contributions shows that the high strength of as-drawn Cu–20Fe alloy is dominantly originated from high-density Fe fibers. Meanwhile, the lower electrical conductivity is ascribed to the high solute Fe content and high-density Cu/Fe heterogeneous phase interface.

Solubility of Cu, Ni, Mn in Boron-Rich Fe-B-C Alloys

In the present study, the microstructure development and mechanical properties of the cast boron-rich Fe–B–C alloys cooled at 10 and 103 K/s were investigated as functions of alloying elements additions. These alloys were prepared in the following compositional ranges: B (10–14 wt.%), C (0.1–1.2 wt.%), M (5 wt.%), where M – Cu, Ni or Mn, balance Fe. Structural properties were characterized by quantitative metallography, X-Ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Mechanical properties of the structural constituents, such as microhardness and fracture toughness, were measured by a Vickers indenter. Copper becomes negligibly incorporated into the phases Fe(B,C) and Fe2(B,C) of the Fe–B–C alloys, but solubility limit forces the remaining solute into the residual liquid. As a result, the globular Cu inclusions are seen in the structure. As compared with copper, nickel has higher solubility in the constituent phases, with preferential solubility observed in the Fe2(B,C) crystals, where Ni occupies Fe positions. Having limited solubility, nickel also forms secondary Ni4B3 phase at the Fe2(B,C) boundaries. Manganese was found to dissolve completely in the Fe–B–C alloys forming substitutional solid solutions preferentially with Fe(B,C) dendrites. By entering into the iron borides structure, Mn and Ni improve their ductility but lower microhardness. The peculiarities in the structure formation and properties of the doped boron-rich Fe–B–C alloys were explained with electronic structure of the alloying elements considered.

Effect of Ti, Al, Si on the Structure and Mechanical Properties of Boron-Rich Fe–B–C Alloys

The effects of substitution of Fe in the boron-rich Fe–B–C alloys, containing 10.0–14.0 % B; 0.1–1.2 % C; Fe – the remainder, 5.0 % Ti, Al, or Si (in wt. %) have been studied with optical microscopy, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy. Mechanical properties, such as microhardness and fracture toughness, have been measured by Vickers indenter. The microstructure of the master Fe–B–C alloys cooled at 10 and 103 K/s consists of primary dendrites of Fe(B,C) solid solution and Fe2(B,C) crystals. It has been found that titanium has the lowest solubility in the constituent phases of the Fe–B–C alloys, with preferential solubility observed in the Fe(B,C) dendrites, where Ti occupies Fe positions. This element has been shown to be mainly present in secondary phases identified as TiC precipitates at the Fe2(B,C) boundaries. Titanium slightly enhances microhardness and lowers fracture toughness of the boron-rich Fe–B–C alloys due to substitutional strengthening of Fe(B,C) dendrites and precipitation of the secondary phases. The level of the content of Al or Si in the Fe(B,C) and Fe2(B,C) solid solutions and quantity of the secondary phases observed in the structure suggest that more Al or Si are left in the constituent phases as compared with Ti. These elements mainly enter the crystal lattice of Fe2(B,C) phase replacing iron atoms and form at their boundaries AlB12C and SiC compounds respectively. The additions of Al and Si to the boron-rich Fe–B–C alloys help to modify their fragility: while they slightly decrease microhardness values, addition of these elements improves the fracture toughness of the constituent phases. Increase in a cooling rate from 10 to 103 K/s does not bring about any noticeable changes in the solubility behavior of the investigated alloying elements. The rapid cooling gives rise to microhardness and fracture toughness of the phase constituents which average sizes significantly decrease. The effects of the alloying elements on the structure and mechanical properties of the investigated boron-rich Fe–B–C alloys have been explained considering differences in the atomic radii and electronic structure of the solute Ti, Al, or Si atoms.

Hierarchical microstructures and deformation behavior of laser direct-metal-deposited Cu–Fe alloys

Cu25Fe75 and Cu50Fe50 (nominal composition, at. %) alloys were fabricated using laser direct metal deposition (DMD) based additive manufacturing technique. These alloys exhibit hierarchical microstructures with bi-phasic Cu and Fe dendrites that contain nanoscale precipitates of varying sizes and structures. In the Cu25Fe75 alloy, Fe dendrites contained nanoscale, coherent, metastable BCC Cu and semi-coherent FCC Cu precipitates while the Cu matrix had nanoscale, coherent, metastable FCC Fe precipitates. In the Cu50Fe50 alloy, Fe dendrites only contained nanoscale semi-coherent FCC Cu precipitates while the Cu matrix had nanoscale coherent metastable FCC Fe precipitates. Both alloys exhibited enhanced flow strengths in the range of 750–980 MPa and significant plasticity, in compression. The Cu25Fe75 alloy had lower yield strength than Cu50Fe50 alloy but higher maximum compressive strength due to higher strain hardening resulting from slightly coarser dendrites with hierarchy of nanoscale precipitation. • Laser direct-metal-deposition based additive manufacturing is used to make Cu–Fe alloys. • Alloys show formation of hierarchical microstructure in Cu matrix and Fe dendrites. • Metastable BCC and FCC Cu precipitates are present in Fe dendrites. • Only coherent metastable FCC Fe precipitates are visible in Cu matrix. • Alloy with more Cu content shows grain refinement and higher yield strength.

Phase composition and microstructure formation mechanism of in-situ Cu-Fe micro-composites

The phase composition and microstructure formation mechanism of in-situ Cu-Fe micro-composites were investigated. The microstructures of longitudinal and transverse sections were analyzed by light microscopy and scanning electron microscopy. The phase analysis was executed by X-ray diffraction. The common microstructure characteristic of Cu-XFe (X = 11, 14 and 17) alloys was that the second phase α-Fe dendrites were uniformly distributed in the Cu matrix. The disorderly distributed Fe dendrites of Cu-14Fe alloy underwent initial inhomogeneous deformation and then were gradually changed into the directionally arranged Fe fibers of in-situ Cu-14Fe micro-composite in the longitudinal section, and were gradually transformed into the irregular V-shaped Fe fibers in the transverse section. The initial inhomogeneous deformation and the irregular V-shaped Fe fibers in the transverse section are closely related to the formation of <110> texture.

Verification of thermoelectric magnetohydrodynamic flow effects on dendritic tip kinetics by in-situ observations

Magnetohydrodynamic flows can be driven by Lorentz forces acting on thermoelectric currents. Their effects on tip velocities of Pd dendrites solidifying from an undercooled melt under magnetic field intensities of up to 6 T were investigated by in-situ observations using a high-speed camera. At low undercoolings, the tip velocities are depressed by magnetic fields of low and high intensities, but recover under an intermediate magnetic field intensity. At high undercoolings, the tip velocities are also depressed, but their recovery is shifted to a higher magnetic field intensity. These observations on Pd dendrites support and extend the findings obtained in previous studies on Ni and Fe dendrites, and fully verify the convection effects on dendritic growth due to three thermoelectric magnetohydrodynamic flow patterns as predicted in recent numerical simulations.

Influences of Alternating Magnetic Fieldson the Growth Behavior and Distribution of the Primary Fe Phasein Cu-14Fe Alloys during the Solidification Process

An alternating magnetic field (AMF) was applied during the solidification process of the Cu-14Fe alloy and the effect of the electromagnetic parameter, which impact the model and solidification technique of the solidification structure that were analyzed. Results show that an AMF applied during the solidification process significantly reduced macro-segregation and gas hole defects. During the growth process of the primary Fe phase, the AMF impacted the nucleation of detached grains and fusing dendrites. Specifically, the developed Fe dendrites were transformed to rosettes or spherical grains in the presence of an applied AMF while the grain distribution was more disperse and uniform. It was found that the growth behavior of Fe grains under AMF depended upon the combined effects of the electromagnetic force and electromagnetic heat.

Influences on Distribution of Solute Atoms in Cu-8Fe Alloy Solidification Process Under Rotating Magnetic Field

A rotating magnetic field (RMF) was applied in the solidification process of Cu-8Fe alloy. Focus on the mechanism of RMF on the solid solution Fe(Cu) atoms in Cu-8Fe alloy, the influences of RMF on solidification structure, solute distribution, and material properties were discussed. Results show that the solidification behavior of Cu–Fe alloy have influenced through the change of temperature and solute fields in the presence of an applied RMF. The Fe dendrites were refined and transformed to rosettes or spherical grains under forced convection. The solute distribution in Cu-rich phase and Fe-rich phase were changed because of the variation of the supercooling degree and the solidification rate. Further, the variation in solute distribution was impacted the strengthening mechanism and conductive mechanism of the material.

Fluid convection and solidification mechanisms of liquid Fe50Cu50 alloy under electromagnetic levitation condition

In the electromagnetic levitation experiment, the liquid flow in the undercooled liquid alloy remarkably affects the relevant thermodynamic property measurement and solidification microstructure. Therefore, it is of great importance to understand the fluid convection inside the undercooled melt. Theoretical calculation and electromagnetic levitation experiment have been used to investigate the internal velocity distribution and rapid solidification mechanism of Fe50Cu50 alloy. Based on axisymmetric electromagnetic levitation model, the distribution patterns of magnetic flux density and inducted current for levitated Fe50Cu50 alloy are calculated together with the mean Lorenz force. The Navier-Stokes equations are further taken into account in order to clarify the internal fluid flow. The results of the theoretical calculation reveal that the fluid velocity within levitated melt is strongly dependent on three factors, i.e., current density, current frequency and melt undercooling. As one of these factors increases, the maximum fluid velocity decreases while the average fluid velocity increases. Meanwhile, the area with fluid velocity larger than 100 mm·-1 is significantly extended. Furthermore, the fluid flow within levitated melt displays an annular tubular distribution characteristic. The Fe50Cu50 alloy melt is undercooled and solidified under electromagnetic levitation condition. In this undercooling regime △ T50Cu50 alloy melt has suppressed phase separation substantially. Once the undercooling attains a value of 150 K, metastable phase separation leads to the formation of layered pattern structure consisting of floating Fe-rich zone and sinking Cu-rich zone. A core-shell macrosegregation morphology with the Cu-rich zone distributed in the center and outside of the sample and Fe-rich zone in the middle occurs if the undercooling increases to 204 K. With the enhancement of undercooling after phase separation, the grain size of α -Fe dendrites in Cu-rich zone presents a decreasing trend. In contrast to the phase separated morphology of Fe50Cu50 alloy under the glass fluxing condition, the phase separated morphologies show obviously different characteristics. In such a case, the forced convection induced by electromagnetic stirring results in the formation of wavy interface between Fe-rich and Cu-rich zones, the distorted morphology of the Cu-rich spheres distributed in the Fe-rich zone, and the increased appearance probabilities of Cu-rich spheres at the upper part of electromagnetically levitated sample. Experimental observations demonstrate that the distribution pattern of Cu-rich spheres in Fe-rich zone is influenced by the tubular fluid flow inside the melt.

Microstructural Evolution and Compressive Properties of Two-Phase Nb-Fe Alloys Containing the C14 Laves Phase NbFe2 Intermetallic Compound

AbstractMicrostructural evolution and compressive properties of two-phase Nb-Fe binary alloys based on the C14 Laves phase NbFe2 were characterized at both the hypo- and hypereutectic compositions. The experimental results indicated that the microstructures of the two alloys consisted of fully eutectics containing Fe and NbFe2 phases at the bottom of the ingots corresponding to the largest solidification rates. With the decrease of solidification rate, the microstructures developed into primary Fe (NbFe2) dendrites plus eutectics in the middle and top parts of the ingots. The microstructural evolutions along the axis of the ingots were analyzed by considering the competitive growth between the primary phase and eutectic as well as using microstructure selection models based on the maximum interface temperature criterion. Furthermore, the compressive properties of the two alloys were measured and the enhancements were explained in terms of the second Fe phase and halo toughening mechanisms.

Rapid solidification mechanism and magnetic property of ternary equiatomic Fe33.3Cu33.3Sn33.3 alloy

Rapid solidification is a typical non-equilibrium phase transition process, and the crystallization rate of liquid metal is larger than 1 cms-1. If the alloy is solidified in this case, the solute segregation is reduced or even eliminated and the solid solubility can be improved significantly. Rapid solidification technique can be used to refine the microstructures of alloys, which provides an effective method to prepare the novel metastable materials and improve their strengths, plasticities magnetic properties, etc. In this work, the rapid solidification mechanism and magnetic property of ternary equiatomic Fe33.3Cu33.3Sn33.3 alloy are investigated by drop tube and melt spinning techniques. It is known that Fe-Cu-Sn ternary alloy forms a typical immiscible system. However, the experimental results reveal that the liquid phase separation does not take place during the rapid solidification of ternary equiatomic Fe33.3Cu33.3Sn33.3 alloy. The solidification microstructures are all composed of primary Fe dendrites together with Cu3Sn and Cu6Sn5 phases. Under the free fall condition, as the drop tube technique provides microgravity and containerless states, the maximum surface cooling rate and maximum undercooling of alloy droplets are 1.3105 Ks-1and 283 K (0.19 TL), respectively. When the surface cooling rate reaches 1.9103 Ks-1, the primary Fe phase appears as coarse dendrites, and its maximum dendrite length is 41 m. Meanwhile, the Cu3Sn and Cu6Sn5 phases are distributed in the Fe interdendritic spacings. Once the surface cooling rate increases up to 3.3103 Ks-1, the morphology of the primary Fe phase transforms from coarse dendrites into broken dendrites. It is found that the cooling rate and undercooling greatly affect the solidification microstructure of alloy droplets. During the melt spinning experiments, since the large temperature gradient exists between the wheel surface and free surface, the solidification microstructure is subdivided into two crystal zones according to the different microstructure morphologies of Fe phase: fine grain (zone I) and coarse grain (zone II), where zone I is characterized by granular grains while zone II has some dendrites with secondary branch. Under the rapid cooling condition, the microstructures of ternary equiatomic Fe33.3Cu33.3Sn33.3 alloy ribbons are refined significantly and show soft magnetic characteristics. As the surface cooling rate increases from 8.9106 to 2.7107 Ks-1, the lattice constant of Fe solid solution rises rapidly and the coercivity increases from 93.7 to 255.6 Oe. Furthermore, the results indicate that the grain size of Fe phase is the main factor influencing the coercivity of alloy ribbons.

Migration and alignment of Fe-rich particles in Cu melt under high magnetic field

The interaction among particles in front of solid-liquid interface during solidification plays a role in determining the trajectories, distribution and sizes of particles, which eventually determines the properties of material. By using the interaction to control the migration of particles, impurity particles can be removed from the melt. A method of using an external high magnetic field to simulate the migration of Fe in Cu melt is proposed. Static high magnetic field (0.1 Tesla and 12 Tesla) and gradient high magnetic field (-92.1 T2/m) are subjected to the solid-liquid mushy zone of Cu-30 wt%Fe alloy. The case without high magnetic field is also investigated for comparison. Both macro- and microstructure of the samples are observed by optical microscope. The results indicate that primary Fe dendrites in Cu-Fe alloy are transformed into spherical Fe-rich particles after solidification in mushy zone, and high magnetic field is capable of changing the migration, distribution and arrangement of Fe-rich particles. In the absence of a static high magnetic field, Fe particles are distributed in Cu melt homogeneously. With increasing the magnetic flux density of imposed static high magnetic field, Fe-rich particles gradually migrate upwards. The migration direction is opposite to the direction of the gravity, and there are no Fe-rich particles kept on the bottom of the samples imposed by magnetic field. In the presence of negative high gradient magnetic field, however, the Fe-rich particles migrate downward and the direction is along the direction of the gravity. A model is built up to clarify the body force of Fe-rich particles and to analyze their movement while they are affected by high magnetic field. The results show that the migration behaviors of Fe-rich particles are related to the viscous dragging force, the interaction force between magnetic dipoles, and the magnetization force induced by gradient high magnetic field. The displacement of Fe particles is closely dependent on the body force. Through the analysis the experimental results are well explained. The diameters of Fe-rich particles are statically summarized under different high magnetic field conditions and in different zones. With increasing magnetic flux density of static high magnetic field, the aggregation of particles is increased. The magnetic field gradient, however, reduces the aggregation of particles. This might be as a result of the competitive coagulation between Stokes sedimentation and Marangoni migration in Cu melt. Microstructure of the samples indicates that Fe-rich particles tend to align along the direction of high magnetic field and the degree of alignment is likely to be related to external magnetic field strength, resistance force, effective time, and initial condition of particles, etc. As they are parallel to the direction of high magnetic field, the energy of the system is minimum, suggesting that the system is stable. The present study shed light on how to remove strong magnetic impurity from Cu melt.

Comparative study of the influence of Ag on the microstructure and mechanical properties of Cu-10Fe in situ composites

Cu-10Fe and Cu-10Fe-3Ag in situ composites were prepared by casting and drawing. The microstructure and properties of the composites were investigated in detail. Results show that the presence of Ag can refine the primary Fe dendrites, which leads to a significantly higher strength of Cu-Fe-Ag composites. For each deformation strain, the tensile strength of the cold-worked Cu-10Fe-3Ag in situ composite was 66 MPa–230 MPa higher than that of the Cu-10Fe in situ composite, and the conductivity of the cold-worked Cu-10Fe-3Ag in situ composite was 1%–4% IACS higher than that of the Cu-10Fe in situ composite. The Cu-10Fe-3Ag in situ composites had a combination of properties with intermediate heat treatment. After 1 h of heat treatment at 450 °C, the tensile strength increased to 968 MPa, and the conductivity increased to 62.6% IACS.

Effect of Alternating Magnetic Field on the Microstructure and Solute Distribution of Cu&amp;ndash;14Fe Composites

The influence of a low frequency alternating magnetic field (LFAMF) during solidification was investigated for Cu-14Fe composites. The microstructure was investigated by optical microscope; the solute distribution in different phases was analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy; the oxygen content was tested by oxygen & nitrogen analyzer; the conductivity was measured by eddy current conductivity meter; and the micro-hardness was measured by Vickers hardness tester. AMF treatment reduced rod shape and large size Fe dendrites, changed some Fe dendrites into club shape and equiaxed grains, and promoted the homogenization of Fe phase distribution. In addition, AMF treatment increased the Cu content in Fe phase and decreased the Fe content in Cu matrix. The effect of AMF during solidification was discussed from the view of thermodynamics and kinetics. This was attributed to the refinement of primary Fe dendrites and the precipitation of Fe atoms from Cu matrix.

Microstructure refinement in Cu-Fe alloy using high pressure torsion

The effect of high pressure torsion (HPT) on the microstructure evolution of Cu-Fe 36% wt alloy has been studied. The initial Cu-Fe alloy has a dendritic structure, the length of dendrites is up to 100 gm. As a result of HPT (20 anvil rotations at 400 °C) the refinement of a- Fe dendrites occurs, and a microstructure with Fe inclusions with a size from 0.1 to 5 gm uniformly distributed in the copper matrix forms. Subsequent annealing at 700 °C for 1 hour results in some coarsening of a-Fe particles, as compared to the state after HPT. However, the dendritic structure typical of the cast alloy does not recover; it remains dispersed with a size of a-Fe particles less than 20 gm. As a result of HPT the alloy microhardness increased from 1800 to 4000 MPa. The subsequent annealing at T = 700 °C decreased the microhardness to 2700 MPa, but this value is 1.5 times higher than that in the initial as-cast state.

Nucleation and Growth of Primary Silicon Crystals in AlSi Alloy after Modification with CuP and Overheating to a Temperature of 920°C

The article describes the process of crystallization of an AlSi17Cu5 (the A3XX.X series according to ASTM standard) alloy which has been modified with 0.05 wt. % P (CuP10 master alloy) and overheated to a temperature of 920°C. It has been shown that, so-called, "time-temperature treatment" (TTT) of alloy in the liquid state, which consists in overheating the alloy to a temperature above Tliq (about 250-300°C), holding at this temperature and rapid cooling, alters the morphology of primary silicon crystals. By the ATD method of thermal analysis, the characteristic temperature of crystallization (Tliq., TEmin., TEmax., TE(Cu), TE(Fe), Tsol.) were determined, and exothermic effects of the modifier and high-degree overheating on the crystallization course of the investigated alloy were examined. A new mechanism of proeutectic crystallization of the a(Al, Me=Cu, Fe) dendrites was proposed. The course of this process is dynamic enough to promote, due to local undercooling, the evolution of heat, which in the ATD curve appears as a well visible additional exothermic effect designated as TX. It is due to the presence in the liquid alloy of microregions with varied content of dissolved silicon.

Influence of a high magnetic field on the microstructure and properties of a Cu–Fe–Ag in situ composite

The influence of a magnetic field during heat treatments was studied for a deformation-processed Cu−14Fe−0.1Ag in situ composite produced by thermo-mechanical processing. A high magnetic field during initial heat treatment promoted the spheroidization and refinement of Fe dendrites, and decreased the diffusion activation energy of Fe atoms in the Cu matrix, which promoted Fe atom precipitation. The resultant in situ composite had thinner Fe fibers, higher tensile strength and better conductivity. A high magnetic field during intermediate heat treatment increased the conductivity and tensile strength. The strength, conductivity and elongation to fracture of a Cu−14Fe−0.1Ag in situ composite could be improved simultaneously using a high magnetic field during the initial, intermediate and final heat treatment. The following combination of properties could be produced by the Cu−14Fe−0.1Ag in situ composite at η=7.8 after isochronic aging for 1h using 10T magnetic induction intensity: (i) 1149MPa tensile strength, 60.3% IACS conductivity and 3.3% elongation; or (ii) 1093MPa, 61.9% IACS and 3.5%; or (iii) 1006MPa, 63.7% IACS and 3.7%.

Enhanced Strength and Electrical Conductivity of Cu&amp;ndash;8Fe Composite by Adding Trace Ag and P

Cu­8Fe­0.5Ag­0.02P (mass%) in situ composites were fabricated by inductive melting and then the as-casted sample drew heavily at room temperature to refine the microstructure and optimize the mechanical and electrical properties. The microstructure evolution of the composite during drawing was investigated, while the tensile strengths and electrical conductivity of the as-drawn samples were measured. Comparing to Cu­8Fe composite, the tensile strength and electrical conductivity were enhanced largely by adding trace Ag and P. The results show that trace Ag refines the primary Fe dendrites and promotes the precipitation of secondary phase Fe particles. Trace P reacts with the solid solution Fe atoms and then facilitates ellipsoid Fe3P particles precipitation. The mechanical strength and electrical conductivity of Cu­8Fe­ 0.5Ag­0.02P were improved obviously, which is attributed to the combined effects of trace Ag and P. [doi:10.2320/matertrans.M2013260]

Effect of composition on the reactivity of Al-rich alloys with water

Fe-bearing Al–Ga–In–Sn alloys were prepared by using arc melting under high purity argon atmosphere. Their microstructures were investigated by means of XRD, SEM/EDX, and the eutectic reaction of Al with grain boundary phase Ga–In–Sn (GIS) was measured using DSC. Fe dendrites were found to present on columnar Al grain surfaces. As the amount of low melting point metals (Ga, In and Sn) is 6 wt.% with a ratio of In:Sn of 15:7, these alloys just consist of Al(Ga) and In3Sn two phases. InSn4 was found in an alloy as its weight ratio of In:Sn approaches 1:1 with an extra addition of Sn (1 wt.%). The reactions of Al alloys with water were performed at different water temperatures ranging from 0.5 to 50 °C. Al reacted with water at a lower water temperature of 0.5 °C, but the reaction suspended within tens of minutes. Once water was heated to a higher temperature of about 15 °C, Al reacted with water again. The H2 generation rates measured at a water temperature of 50 °C depend on the compositions of alloys. Reasons concerning the reactivity of Al–water at different temperatures are discussed.

Morphology evolution of dendritic Fe wire array by electrodeposition, and photoelectrochemical properties of α-Fe2O3 dendritic wire array

In this paper, dendritic iron wire array films with different morphologies were prepared on Cu/ITO and slide ITO glass substrates by electrodeposition. The morphologies of Fe films obtained at different conditions were characterized by scanning electron microscopy. The growth mechanism of the dendritic Fe array is described by changing the ratio of deposition rate to mass transport rate (R) according to the experimental results. The variable R affects the final structure of the products. Especially, Fe dendrites can grow vertically layer by layer. The photoelectrochemical properties indicate that dendritic hematite (α-Fe2O3) arrays have a poor electron-hole (e–h) recombination effect.