Influence of microstructure on the corrosion resistance of Fe–44Ni thin films

An Fe–44Ni nanocrystalline (NC) alloy thin film was prepared through electrodeposition. The relation between the microstructure and corrosion behavior of the NC film was investigated using electrochemical methods and chemical analysis approaches. The results show that the NC film is composed of a face-centered cubic phase (γ-(Fe,Ni)) and a body-centered cubic phase (α-(Fe,Ni)) when it is annealed at temperatures less than 400℃. The corrosion resistance increases with the increase in grain size, and the corresponding corrosion process is controlled by oxygen reduction. The NC films annealed at 500℃ and 600℃ do not exhibit the same pattern, although their grain sizes are considerably large. This result is attributed to the existence of an anodic phase, Fe_0.947Ni_0.054, in these films. Under this condition, the related corrosion process is synthetically controlled by anodic dissolution and depolarization.     

Dependence of Magnetic Properties and Microstructure of Ni81Fe19 Film on Base Vacuum and Sputtering Pressure

The Ni81Fe19 / Ta films with different NiFe thickness were prepared at different base vacuums and sputtering pressures. The results of magnetic measurement and atomic force microscope (AFM) showed that the films prepared at higher base vacuum and lower sputtering pressure had larger R/R. The reason should be that higher base vacuum and lower sputtering pressure introduce larger grain-size and lower surface roughness, which will weaken the scattering of electrons, reduce the resistance R, and increase R/R.     

CeO2 thin films grown on biaxially textured nickel (001)

CeO\-2 films have been grown on biaxially textured Ni substrates at various temperatures. The results show that CeO\-2 films without IBAD are dominated by (111) orientation from room temperature to 800℃ while the preferential orientation of CeO\-2 films with IBAD is (001) at lower deposition temperature and (111) at deposition temperature higher than 450℃. CeO\-2 films with better in_plane texture and out_of_plane orientation can be grown at 360℃ with 240 eV ion energy and 200 μA/cm\+2 ion current density.     

Magnetic properties and structure of very thin permalloy films

In order to study the magnetic properties and structure of very thin permalloy films, Ni₈₁Fe₁₉ films of 12 nm in thickness were prepared by different instruments at an ultrahigh base vacuum and a lower base vacuum. The anisotropic magnetoresistance coefficients (△R/R) of Ni₈₁Fe₁₉ (12 nm) films reached 1.6 % and 0.6 %, and the coercivities were 127 and 334 A/m, respectively. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to study the structure and surface chemical state. The experimental results show that the films prepared at the ultrahigh base vacuum have a smoother surface, a bigger grain size and a denser structure with fewer defects than those prepared at the lower base vacuum.     

Hardness variations during aging process of deformed W-Ni-Fe ternary alloys with high nickel-to-iron ratios

The aging precipitation behavior of β phase in two kinds of alloys with 7/3 and 9/1 nickel-to-iron ratios during aging at 800℃ after deformation was studied. The results show that there are two different kinds of aging hardness variation mechanisms (the softening mechanism and the hardening mechanism) deciding the hardness variations of the alloys. When Ni/Fe is smaller than 8/2, there is only the softening mechanism which results from the decreasing of dislocation density and recovery or re-crystallization.And when Ni/Fe is greater than 8/2 besides the softening mechanism there is still the hardening mechanism that is induced by the precipitation of β phase.     

Structure and ~(57)Fe conversion electron Mssbauer spectroscopy study of Mn-Zn ferrite nanocrystal thin films by electroless plating in aqueous solution

Mn1-xZnxFe2O4 thin films with various Zn contents and of different thickness were synthesized on glass substrates directly by electroless plating in aqueous solution at 90℃ without heat treatment.The Mn-Zn ferrite films have a single spinel phase structure and well-crystallized columnar grains growing perpendicularly to the substrates.The results of conversion electron 57Fe M?ssbauer spectroscopy(CEMS)indicate that the cation distribution of Mn1-xZnxFe2O4 ferrite nanocrystal thin films fabricated by electroless plating is different from the bulk materials' and a great quantity of Fe3 ions are still present on A sites for x>0.5.When the Zn content of the films increases,Fe3 ions in the films transfer from A sites to B sites and the hyperfine magnetic field reduces,suggesting that Zn2 has strong chemical affinity towards the A sites.On the other side,with the increase of the thickness of the films,Fe3 ions,at B sites in the spinel structure,increase and the array of magnetic moments no longer lies in the thin film plane completely.At x = 0.5,Hc and Ms of Mn1-xZnxFe2O4 thin films show a minimum of 3.7 kA/m and a maximum of 419.6 kA/m,respectively.     

Giant magneto-impedance and low-frequency magneto-resistance effect in NiFeB coated composite wires

Composite wires of 100 μm insulated CuBewire plated with a layer of NiFeB were produced by elec-troless-deposition, and their magnetic properties were stud-led. The results showed that a good magneto-impedance (MI)effect can be obtained at relatively low frequency. The largestMI ratio (△Z/Z)max obtained is 250% at 500 kHz. Mag-neto-resistance effect was also observed at low frequency,with the (△R/R)max observed to be -8.5% at 540 Hz and 38.7% at 10 kHz. Results are discussed, and the equivalent resistance and inductance as the result of the NiFeB layer are taken into account.     

Study on NiO/Fe interface with X-ray photoelectron spectroscopy

Different monolayers (ML) of Fe atoms were deposited on NiO (001) substrates or NiO underlayers using molecular beam epitaxy (MBE), pulse laser deposition (PLD), and magnetron sputtering (MS). The magnetic properties and microstructure of the films were studied. The apparent magnetic dead layer (MDL) is found to exist at the NiO/Fe interfaces of the MBE sample (about 2 ML MDL), the PLD sample (about 3 ML MDL), and the MS sample (about 4 ML MDL). X-ray photoelectron spectroscopy indicates the presence of ionic Fe (Fe2+ or Fe3+) and metallic Ni at the NiO/Fe interfaces, which may be due to the chemical reactions between Fe and NiO layers. This also leads to the formation of MDL. The thickness of the MDL and the reaction products are related with the deposition energy of the atoms on the substrates. The interfacial reactions are effectively suppressed by inserting a thin Pt layer at the NiO/Fe interface.     

Influence of pulsing current on the glass transition and crystallizing kinetics of a Zr base bulk amorphous alloy

Based on the thermal analysis, the influence of pulsing current on the glass transition and crystallizing kinetics of Zr41.3Ti14.2CU12.8Ni10.3Be21.4 bulk amorphous alloy has been studied. The obtained results show that after the Zr41.3Ti14.2CU12.8Ni10.3Be21.4 bulk amorphous alloy was pretreated by high-density pulsing current at low temperature, its glass transition temperature Tg, the initial crystallizing temperature Tx and the corresponding exothermic peak of crystallization Tpi were reduced. But the temperature range of supercooled liquid △T=Tx-Tg is almost the same. The calculated results with Kissinger equation show that the activation energy of glass transition of the alloy pretreated is reduced significantly, while the activation energy of crystallization is basically unchanged. The influence of pulsing current on the glass transition and crystallization of theZr41.3Ti14.2CU12.8Ni10.3Be21.4 bulk amorphous alloy is believed to be related with the structure relaxation of the glass caused by the current.     

Ab initio research on DNA base alkylation by theβ-position me-tabolite of methylethylnitrosamine

Ab initio calculation is carried out to study the different supposed mechanisms of DNA base alkylation by [β-sulphate-nitrosamines at RHF/6-31G(d) and MP2/6-31G(d) levels. Full geometric structure optimization is done for all reactants, intermediates, products and transition states. The activation energy and IRC are obtained. The results show that the anchimeric assistant effect promotes the alkylation of DNA base by β-sulphate-nitrosamines. Solvent calculation is carried out with Onsager model of SCRF method at the same level. The results indicate that the activation energy is decreased obviously in water.     

Structure and 57Fe conversion electron Mössbauer spectroscopy study of Mn-Zn ferrite nanocrystal thin films by electroless plating in aqueous solution

Mn1-xZnxFe2O4thin films with various Zn contents and of different thickness were synthesized on glass substrates directly by electroless plating in aqueous solution at 90℃ without heat treatment. The Mn-Zn ferrite films have a single spinel phase structure and well-crystallized columnar grains growing per- pendicularly to the substrates. The results of conversion electron ^57Fe Mossbauer spectroscopy （CEMS） Indicate that the cation distribution of Mn1-xZnxFe204 ferrite nanocrystal thin films fabricated by electroless plating is different from the bulk materials＇ and a great quantity of Fe^3＋ ions are still present on A sites for x〉0.5. When the Zn content of the films increases, Fe^3＋ ions in the films transfer from A sites to B sites and the hyperfine magnetic field reduces, suggesting that Zn2. has strong chemical affinity towards the A sites. On the other side, with the increase of the thickness of the films, Fe3＋ ions, at B sites in the spinel structure, increase and the array of magnetic moments no longer lies in the thin film plane completely. At x = 0.5, Hc and Ms of Mn1-xZnxFe204thin films show a minimum of 3.7 kA/m and a maximum of 419.6 kA/m, respectively.     

The Influence of Transmutation Conditions on the Adulteration Performance of Nano—scale Nickel Hydroxide

Spherical Nano-scale nickel hydroxide was prepared through precipitaition transmutation method by controlling the transmutation conditions in this paper.The measurement results of XRD and TEM indicate that the crystallization of the nano-Scale nickel hydroxide is β-style and its shape is spherical with a diameter of 40-70 nanometer.The adulteration experiment shows that the adulteration ratio of nono-scale Ni(OH)2 in common spherical micrometer-scale Ni(OH)2 exists a optimal value(1:9) And at this point,the utilization ratio of Ni(OH)2 in electrodes can be raised by 10%,and the nono-Scale nickel hydroxide with sphericity shape shows a better adulteration performance than that with needle shapge.     

Theoretical study on Fe-Al clusters: geometric structure, bonding law and electronic structures

Structures of the small Fe-Al clusters with different atom proportion are calculated using the B3LYP method in density functional theory (DFT). Calculated results show that the Al atoms lose electrons easily while the Fe atoms capture electrons easily. The most stable geometry is the bonding between Fe and Fe atoms and between Fe and Al atoms with the largest possibility, and the cluster stability law with the same atom proportion accords with the change of the highest occupied molecular orbital (HOMO) energy and the entropy of cluster system. Moreover, the electronic structure study of the ground-state Fe3Al and Fe2CrAl clusters shows that the substitution of Cr atom for the Fe atom located at the next neighboring site of Al atom reduces localized electrons not only between Al atom and the next neighboring Cr atom, but also between Al atom and the nearest neighboring Fe atom. Although the substitution increases the plasticity and the magnetism of intermetallic compound, the stability of the system slightly decreases. Our theoretical results agree well with the experimental results.     

Effect of pickling processes on the microstructure and properties of electroless Ni–P coating on Mg–7.5Li–2Zn–1Y alloy

The electroless plating Ni–P is prepared on the surface of Mg–7.5Li–2Zn–1Y alloys with different pickling processes.The microstructure and properties of Ni–P coating are investigated.The results show that the Ni–P coatings deposited using the different pickling processes have a different high phosphorus content amorphous Ni–P solid solution structure,and the Ni–P coatings exhibit higher hardness.There is higher phosphorus content of Ni–P amorphous coating using 125 g/L Cr O3and 110 ml/L HNO3(w68%)than using 180 g/L Cr O3and 1 g/L KF during pre-treatment,and the coating structure is more compact,and the Ni–P coatings exhibit more excellent adhesion with substrate(Fcup to22 N).The corrosion potential of Ni–P coating is improved and exhibits good corrosion resistance.As a result,Mg-7.5Li-2Zn-1Y alloy is remarkably protected by the Ni–P coating.     

Effects of Fe content on the microstructure and properties of CuNi10FeMn1 alloy tubes fabricated by HCCM horizontal continuous casting

Heating-cooling combined mold (HCCM) horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuNi10FeMn1 alloy tubes with different Fe contents. The effects of Fe content (1.08wt%–2.01wt%) on the microstructure, segregation, and flushing corrosion resistance in simulated flowing seawater as well as the mechanical properties of the alloy tubes were investigated. The results show that when the Fe content is increased from 1.08wt% to 2.01wt%, the segregation degree of Ni and Fe elements increases, and the segregation coefficient of Ni and Fe elements falls from 0.92 to 0.70 and from 0.92 to 0.63, respectively. With increasing Fe content, the corrosion rate of the alloy decreases initially and then increases. When the Fe content is 1.83wt%, the corrosion rate approaches the minimum and dense, less-defect corrosion films, which contain rich Ni and Fe elements, form on the surface of the alloy; these films effectively protect the α-matrix and reduce the corrosion rate. When the Fe content is increased from 1.08wt% to 2.01wt%, the tensile strength of the alloy tube increases from 204 MPa to 236 MPa, while the elongation to failure changes slightly about 46%, indicating the excellent workability of the CuNi10FeMn1 alloy tubes.     

Tin recovery from a low-grade tin middling with high Si content and low Fe content by reduction–sulfurization roasting with anthracite coal

A new method for separating and recovering tin from a low-grade tin middling with high Si content and low Fe content by roasting with anthracite coal was researched by studying the reaction mechanism and performing an industrial test, in which the Sn was sulfurized into Sn S(g) and then collected using a dust collector. The Fe–Sn alloy may be formed at roasting temperatures above 950°C, and like the roasting temperature increases, the Sn content and Sn activity in this Fe–Sn alloy decrease. Also, more FeS can be formed at higher temperatures and then the formation of FeO–FeS with a low melting point is promoted, which results in more serious sintering of this low-grade tin middling.And from the thermodynamics and kinetics points of view, the volatilization of the Sn decreases at extremely high roasting temperatures. The results of the industrial test carried out in a coal-fired rotary kiln show that the Sn volatilization rate reaches 89.7% and the Sn is concentrated in the collected dust at a high level, indicating that the Sn can be effectively extracted and recovered from the low-grade tin middling with a high Si content and low Fe content through a reduction–sulfurization roasting process.     

Effect of different additives on the properties of lithium alanate

LiAIH₄ doped with Ni and Ce(SO₄)₂ additives and the effect of doping on temperature and hydrogen release were studied by pressure-content-temperature (PCT) experiment and X-ray diffraction (XRD) analysis. It is indicated that doping with Ni induces a significant decrease in temperature in the first step and LiAlH₄ doped with 1mol% Ni presents the most absorption of hydrogen. Doping with Ce(SO₄)₂ also causes a marked decrease, while the amount of hydrogen release changes only slightly. The results from X-ray diffraction analysis show that doping does not cause any structural change; Ni and Ce-containing phases are not observed at room temoerature or even at 250℃.     

Structure,magnetic properties and giant magneto-striction studies in [Tb/Fe/Dy]_n nano-multilayer film

[Tb/Fe/Dy]n nano-multilayer films, with precise composition of Tb0.27Dy0.73Fe2, were prepared by the multi-targets magnetron sputtering technique at room temperature (sample A) and 300℃ substrate temperature (sample B). Both of the nano-multilayer films show columnar structures perpendicular to the film plane according to the scanning electron microscopy results. The magnetic hysteresis loops and the giant magnetostriction (GMS) property of the two samples indicate the perpendicular anisotropy in them. In s...     

Colossal magnetoresistive p-n junctions of perovskite oxide La0.9Sr0.1MnO3／SrNb0.01Ti0.99O3

We have successfully fabricated the colossal magnetoresistive (CMR) p-n junctions of perovskite oxide La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 (LSMO/SNTO) with laser molecular beam epitaxy. The I-V characteristics of the LSMO/SNTO p-n junctions as a function of applied magnetic field (0—5 T) were studied between 100 and 300 K. We found that the p-n junction exhibited the CMR behavior. The CMR ratio △R/R0 (△R = RH - R0) is positive in magnetic fields below 0.13 T and at high temperature, while it displays a negative CMR near 100 K and in magnetic fields over 0.13 T. The CMR ratio values are 8% at 0.1 T and 13% at 5 T and 300 K, 40% at 0.1 T and 150 K, 10% at 0.13 T and -60% at 5 T and 100 K. The CMR behavior of the p-n junction is different from those of the LaMnO3 compound family.