Iron-rich Alloys Research Articles

First-principles simulations of liquid iron-heavy element alloys at high pressure

Iron-rich metallic liquid in the Earth's outer core is thought to contain many elements. While the incorporation of light elements in liquid iron has been widely studied, liquid iron-heavy element mixtures, particularly considering Co, Mo, and W which are relevant in constraining core-forming conditions need more studies. Here we investigate the thermodynamic and structural behavior of these siderophile elements and Ni dissolved in liquid iron in the amount of 2.67 atom% using first-principles molecular dynamics over the pressure range of the entire Earth's interior at temperatures 4000 to 7000 K. The calculated pressure-volume-temperature results of these iron-rich alloys are accurately described by adding the appropriative terms to the equation of state of pure iron liquid to account for the effects of temperature and impurity. The calculated mean iron coordination number of Mo and W is somewhat larger than that of Ni and Co and host iron atoms thus implying substitutional incorporation mechanism. The lack of clustering activity among the impurity atoms means that each of these impurity elements is soluble in liquid iron. Our analysis also shows that Mo and W increase the liquid density much more than Ni and Co mainly for mass reason while the bulk modulus remains essentially unaffected in all cases. The presence of heavy elements widens the apparent density gap between iron-rich liquid and the outer core so additional amounts of lighter impurity elements should be considered when constraining the core composition.

The iron spin transition of deep nitrogen-bearing mineral Fe3N1.2 at high pressure

Abstract Nitrogen is an essential element for life, one of the most abundant volatiles in the atmosphere, and an important component in the Earth’s interior, where iron nitride is an essential host of deep nitrogen. Here, we investigate the pressure-induced electronic spin-pairing transition of iron in siderazot (Fe3N1.2) at pressures up to 45.8 GPa at room temperature, using diamond-anvil cell techniques coupled with synchrotron X-ray emission spectroscopy. The integrated intensity of the satellite emission peak (K′β) decreases upon compression but remains unchanged at pressures greater than 30.5 GPa. In other words, the high-spin to low-spin transition of iron in Fe3N1.2 starts immediately at very low pressures and completes at ~30.5 GPa. The iron spin transition completion pressures increase with the nitrogen concentration of hexagonal close-packed iron nitrides (i.e., Fe3N1.2, Fe7N3, and Fe2N). Moreover, the identity and concentration of light elements in binary iron-rich compounds such as Fe3N, Fe3C, Fe3P, Fe3S, Fe7C3, and Fe7N3, together with their crystal structure, could affect the iron spin transition pressures. The spin transition of iron-rich alloys could alter the bonding nature and the physical properties, including the thermal and electrical conductivity, thereby influencing the thermal state and evolution of planetary interiors.

Re-entrant ferromagnetism at ultrahigh temperatures in epsilon–iron as possible origin of the geomagnetic field

A recent theory of band ferromagnetism in 3d metals predicts ‘re-entrant’ ferromagnetism at temperatures far above the boiling point of these metals in normal conditions (Teodorescu, C.M., 2021. Spin asymmetry originating from densities of states: Criterion for ferromagnetism, structures and magnetic properties of 3d metals from crystal field based DOSs. Results in Physics 25, 104,241). Metals, and in particular iron rich alloys, are still solid at such extremal temperatures in the Earth’s inner solid core. It follows that this piece of the Earth may become ferromagnetic. This hypothesis is investigated in this work in more details, by using densities of states derived by ab initio density functional theory calculations for hexagonal close-packed iron and applying the basic theory of band ferromagnetism derived in the above Reference. The temperature for ‘re-entrant’ ferromagnetism increases with the pressure, ranging between about 6530 and 6640 K for pressures between 330 and 360 GPa; these temperatures are in the range of most estimates for the temperature of the inner solid core of our planet. The dimension of the ferromagnetic “innermost inner core” (IMIC) derived from the estimated Fe magnetic moment are within the dimensions of a IMIC with different anisotropy in the propagation of seismic waves. For body centered cubic Fe no ‘re-entrant’ ferromagnetism is predicted based on the actual model. It follows that the Earth’s inner solid core with hexagonal close-packed structure is the main responsible for the geomagnetic field, and also most probably the reversal of this field proceeds by simple rotation of the magnetization of this core, while keeping a non-vanishing magnetic field during the reversal. This might prevent the Earth’s surface bombardment with energetic charged particles during the reversals, with beneficial effects for complex lifeforms and for mankind civilization.

A speciation model linking the fate of carbon and hydrogen during core – magma ocean equilibration

The core – mantle differentiation in the magma ocean constitutes a major planetary event that involved two elements that are essential to life: carbon (C) and hydrogen (H). These two elements are conventionally classified as volatiles (i.e. atmophile), but they can also evolve into being siderophile and lithophile at the extreme conditions found in planetary magma oceans. We report here a model for H and C species dissolved in silicate melts in equilibrium with iron-rich alloys under variable pressure, temperature and redox conditions. This speciation model is able to reconcile and reproduce a large body of experimental data on metal–silicate partitioning for H and C at carbon-saturation and in C-undersaturated systems. At low pressure, we conclude that the prevailing species in a silicate magma ocean are CO2, CO, H2O, H2, whereas CH4 appears to dominate at high pressure. These speciation changes explain recent experimental observations that (i) C evolves from being strongly siderophile at low pressure to moderately siderophile at high pressure, and (ii) H is not siderophile at low pressure but becomes increasingly so as pressure rises. Moreover, it shows that H becomes increasingly siderophile as the total H content of the silicate melt and C-activity are lowered. Despite it offers a promising reconciliation of a large set of experimental and molecular dynamics observations, this model still suffers from large uncertainties when extrapolated to high pressure. In particular, endmember and mixing properties in both the silicate melt and the molten metal must be independently deciphered.The enhanced CH4 stability in the silicate melt at high pressure couples the fate of C and H in deep magma oceans. In such cases, the solubility of C in the basal ocean depends on the H-content and is higher than C-solubility at low pressure. This implies an increase in C activity as the ascending convective cells of the magma ocean, which may cause C saturation as graphite or diamond unless Fe-metal droplets, having a great C-solubility, are present in the shallow magma ocean. Under certain conditions, enhanced siderophile behaviour for H can lead via a runaway process to the desiccation of the magma ocean.

The Effect of the In-Situ Heat Treatment on the Martensitic Transformation and Specific Properties of the Fe-Mn-Si-Cr Shape Memory Alloys Processed by HSHPT Severe Plastic Deformation.

This work focuses on the temperature evolution of the martensitic phase ε (hexagonal close packed) induced by the severe plastic deformation via High Speed High Pressure Torsion method in Fe57Mn27Si11Cr5 (at %) alloy. The iron rich alloy crystalline structure, magnetic and transport properties were investigated on samples subjected to room temperature High Speed High Pressure Torsion incorporating 1.86 degree of deformation and also hot-compression. Thermo-resistivity as well as thermomagnetic measurements indicate an antiferromagnetic behavior with the Néel temperature (TN) around 244 K, directly related to the austenitic γ-phase. The sudden increase of the resistivity on cooling below the Néel temperature can be explained by an increased phonon-electron interaction. In-situ magnetic and electric transport measurements up to 900 K are equivalent to thermal treatments and lead to the appearance of the bcc-ferrite-like type phase, to the detriment of the ε(hcp) martensite and the γ (fcc) austenite phases.

Magnetic carbon nanotubes: Carbide nucleated electrochemical growth of ferromagnetic CNTs from CO2

This study demonstrates that CO2 can be split by molten carbonate electrolysis (1) to grow magnetic carbon nanotubes (CNTs) and (2) that the process can be initiated by carbide nucleation points acting as growth catalysts. This opens the path to other similar electrochemically prepared magnetic carbon nanomaterials. Magnetic carbon nanomaterials have a variety of applications, such as in directing medical therapy to localized regions and recoverable catalysts. In the presence of an iron or nickel containing case to house the molten carbonate electrolysis, or the presence of Fe or Ni in the electrochemical components, ferromagnetic CNTs can grow at the cathode. For example, EDS elemental analysis confirms the presence of iron in the CNTs, and XRD confirms the presence of iron carbide at the CNT nucleation site. The observed interlattice spacing of 0.20 nm of the iron carbide is distinct from the observed 0.36 nm graphene lattice spacing of the CNT walls. An excess iron release can be facilitated into the electrolyte using an iron rich alloy anode, such as Incoloy. The excess iron results in graphene layer coated iron carbide nodules on the exterior of the carbon nanotube product formed at the cathode, as well as iron carbide within these CNTs as observed by SEM and TEM.

Integrating Flotation and Pyrometallurgy for Recovering Graphite and Valuable Metals from Battery Scrap

Since the current volumes of collected end-of-life lithium ion batteries (LIBs) are low, one option to increase the feasibility of their recycling is to feed them to existing metals production processes. This work presents a novel approach to integrate froth flotation as a mechanical treatment to optimize the recovery of valuable metals from LIB scrap and minimize their loss in the nickel slag cleaning process. Additionally, the conventional reducing agent in slag cleaning, namely coke, is replaced with graphite contained in the LIB waste flotation products. Using proper conditioning procedures, froth flotation was able to recover up to 81.3% Co in active materials from a Cu-Al rich feed stream. A selected froth product was used as feed for nickel slag cleaning process, and the recovery of metals from a slag (80%)–froth fraction (20%) mixture was investigated in an inert atmosphere at 1350 °C and 1400 °C at varying reduction times. The experimental conditions in combination with the graphite allowed for a very rapid reduction. After 5 min reduction time, the valuable metals Co, Ni, and Cu were found to be distributed to the iron rich metal alloy, while the remaining fraction of Mn and Al present in the froth fraction was deported in the slag.

Correlation between microstructure and magnetic properties during phase separation in concentrated Fe-Cr alloys

We report a theoretical study of microstructure, magnetic properties, and their relationship in relatively concentrated Fe-Cr alloys in both Fe- and Cr-rich regions. Annealing of initially random systems at 500 °C for times of the order of 106 s substantially changes their microstructure. In both systems, solute atoms form clusters with their sizes increasing with time according to power law, with exponent being close to 0.2. For the Fe-32 at. % Cr alloy, magnetization and the Curie temperature increase with increasing annealing time and cluster size. At large simulation times, the Curie temperature approaches its value for Fe-15 at. % Cr, the concentration of completely phase-separated iron-rich alloy. For the Cr-25 at. % Fe alloy, precipitation also results in an increase of magnetization and the Curie temperature, although characteristic times are about one order of magnitude greater.

Magnetic, Magnetoelastic and Corrosion Resistant Properties of (Fe-Ni)-Based Metallic Glasses for Structural Health Monitoring Applications.

We have performed a study of the magnetic, magnetoelastic, and corrosion resistance properties of seven different composition magnetoelastic-resonant platforms. For some applications, such as structural health monitoring, these materials must have not only good magnetomechanical properties, but also a high corrosion resistance. In the fabricated metallic glasses of composition , the Fe/Ni ratio was varied (Fe + Ni = 73% at.) thus changing the magnetic and magnetoelastic properties. A small amount of chromium was added in order to achieve the desired good corrosion resistance. As expected, all the studied properties change with the composition of the samples. Alloys containing a higher amount of than do not show magnetic behavior at room temperature, while iron-rich alloys have demonstrated not only good magnetic properties, but also good magnetoelastic ones, with magnetoelastic coupling coefficient as high as for in the (the sample containing only but not ). Concerning corrosion resistance, we have found a continuous degradation of these properties as the content increases in the composition. Thus, the corrosion potential decreases monotonously from 46.74 mV for the , composition to −239.47 mV for the , composition .

Mineralogy, Structure, and Habitability of Carbon-Enriched Rocky Exoplanets: A Laboratory Approach.

Carbon-enriched rocky exoplanets have been proposed to occur around dwarf stars as well as binary stars, white dwarfs, and pulsars. However, the mineralogical make up of such planets is poorly constrained. We performed high-pressure high-temperature laboratory experiments (P = 1-2 GPa, T = 1523-1823 K) on chemical mixtures representative of C-enriched rocky exoplanets based on calculations of protoplanetary disk compositions. These P-T conditions correspond to the deep interiors of Pluto- to Mars-sized planets and the upper mantles of larger planets. Our results show that these exoplanets, when fully differentiated, comprise a metallic core, a silicate mantle, and a graphite layer on top of the silicate mantle. Graphite is the dominant carbon-bearing phase at the conditions of our experiments with no traces of silicon carbide or carbonates. The silicate mineralogy comprises olivine, orthopyroxene, clinopyroxene, and spinel, which is similar to the mineralogy of the mantles of carbon-poor planets such as the Earth and largely unaffected by the amount of carbon. Metals are either two immiscible iron-rich alloys (S-rich and S-poor) or a single iron-rich alloy in the Fe-C-S system with immiscibility depending on the S/Fe ratio and core pressure. We show that, for our C-enriched compositions, the minimum carbon abundance needed for C-saturation is 0.05-0.7 wt% (molar C/O ∼0.002-0.03). Fully differentiated rocky exoplanets with C/O ratios more than that needed for C-saturation would contain graphite as an additional layer on top of the silicate mantle. For a thick enough graphite layer, diamonds would form at the bottom of this layer due to high pressures. We model the interior structure of Kepler-37b and show that a mere 10 wt% graphite layer would decrease its derived mass by 7%, which suggests that future space missions that determine both radius and mass of rocky exoplanets with insignificant gaseous envelopes could provide quantitative limits on their carbon content. Future observations of rocky exoplanets with graphite-rich surfaces would show low albedos due to the low reflectance of graphite. The absence of life-bearing elements other than carbon on the surface likely makes them uninhabitable.

4D full-vector radio frequency complex magnetic susceptibility mapping. Near-field imaging of RFID tags

Radio frequency identification (RFID) is a technology permeating both everyday life and scientific applications alike. The most prolific passive tag-based system uses inductively-powered tags with no internal power source [V. Chawla and D. S. Ha, “An overview of passive RFID,” IEEE Commun. Mag. 45(9), 11–17 (2007)]. Here we demonstrate an inductive magnetic field mapping platform on the example of passive near-field RFID tags (ID-1), operating at 13.56 MHz (HF) [Identification cards - Contactless integrated circuit(s) cards - Proximity cards - Part 1: Physical characteristics, ISO/IEC 14443-1, 2000; Part 2: Radio frequency power and signal interface, ISO/IEC 14443-2, 2010; Part 3: Initialization and anticollision, ISO/IEC 14443-3, 2011; Part 4: Transmission protocol, ISO/IEC 14443-4, 2008]. With smaller modules currently being integrated in wrist-bands, watches and items of jewelry, a possible counter-measure to the reduced size is the use of flux-concentrating magnetic material - low-permeability insulating ferrites or high-permeability metallic μ-particle systems such as sendust. Sendust is a magnetically soft iron-rich alloy of Fe, Al and Si - a higher permeability cheaper alternative to permalloy. The integration of sendust components in RFID tags creates a non-trivial multiple-parameter optimization problem, which requires a quantitative RF field imaging system to be used. The RF susceptibility mapping system is comprised of a stepper-motor-driven 4-axial table, which holds the device under test (DUT) or the RFID tag assembly, a source coil (2 turns of 0.5 mm diameter wire, of overall diameter of 21 cm), a 4-micro-coil assembly, allowing for the measurement of Hx, Hy, Hz and dHz/dz, and a 4-channel Vector Network Analyzer (VNA). Four complex transmission spectra are obtained for each spatial point of a rectangular (x, y) grid, and then repeated for a different z-cut. 4D Complex Vector field maps are thus obtained. Simultaneous fitting of the real and imaginary parts of the frequency spectra is possible, at essentially any point of space, to a model comprised of two damped harmonic oscillators. This type of 3D-spatial, full-vector, complex magnetic susceptibility imaging opens ways to the integration of magnetic materials in near-field systems, and is not limited to RFID.

Alloy disorder and fluctuating magnetic moments in the Earth’s core

Abstract The electronic and thermal transport properties of the Earth’s core are crucial for many geophysical models such as the geodynamo model of the Earth’s magnetic field. We show by first-principles modeling and methods of statistical physics that the spin disorder, not considered in previous studies, gives an essential contribution to the electrical resistivity at the Earth’s core conditions. The origin of this spin-disorder resistivity (SDR) consists in the existence of fluctuating local moments that are stabilized at high temperatures by the magnetic entropy even at pressures at which the ground state of iron is non-magnetic. It turns out that the contributions of various scattering mechanisms (alloy disorder, phonon scattering, spin disorder, and electron-electron correlations) are comparable, but not additive. Here we report results for iron and iron-rich alloys (Fe-O, Fe-Si, Fe-S) that can be present in the Earth’s core. Special attention is paid to alloys with two magnetic elements (Fe-Ni).

Study of Mechanical and Wear Behaviour of Hyper-Eutectic Al-Si Automotive Alloy Through Fe, Ni and Cr Addition

Effect of Fe, Ni and Cr addition on the wear behavior of hyper-eutectic Al-Si automotive alloy has been studied. Dry sliding wear tests have been conducted using pin-on-disc wear testing machine under normal loads of 20N and constant sliding speed of 0.64 ms-1. Influence of Fe addition to the base alloy increases the wear rate due to the formation of needle beta intermetallics. Ni addition to the alloy does not impede formation of needle-like intermetallic compounds and has no positive effect on the modification of microstructure. Introducing of Cr to the iron-rich alloy changes the beta intermetallics into the modified alpha phases and therefore reduced the detrimental effect of iron. As a result it recovers the strength and wear properties of the experimental alloy. Wear test surfaces were examined by SEM and have shown that Cr added alloy improves wear resistance through mild and smooth abrasive grooves filled with oxides.

Recovery of metal values from copper slag and reuse of residual secondary slag

Resource and environmental factors have become major forces in mining and metallurgy sectors driving research for sustainability purposes. The concept of zero-waste processing has been gaining ground readily. The scant availability of high quality raw materials has forced the researchers to shift their focus to recycling while the exceedingly stringent environmental regulations have forced researchers to explore new frontiers of minimizing/eliminating waste generation. The present work is aimed at addressing both aspects by employing recycling to generate wealth from copper slag and producing utilizable materials at the same time thus restoring the ecosystem. Copper slag was characterized and processed. The pyro-metallurgical processing prospects to generate utilizable materials were arrived at through rigorous thermodynamic analysis. Carbothermal reduction at elevated temperature (near 1440°C) helped recover a majority of the metal values (e.g., Fe, Cu and Mo) into the iron-rich alloy product which can be a feed material for steel making. On the other hand, the non-metallic residue, the secondary slag, can be used in the glass and ceramic industries. Reduction time and temperature and carbon content were shown to be the most important process variables for the reaction which were optimized to identify the most favored operating regime that maximizes the metal recovery and simultaneously maximizes the hardness of the secondary slag and minimizes its density, the two major criteria for the secondary slag product to be utilizable. The flux addition level was shown to have relatively less impact on the process performance if these are maintained at an adequate level. The work established that the copper slag, a waste material, can be successfully processed to generate reusable products through pyrometallurgical processing.

Iron isotopic fractionation between silicate mantle and metallic core at high pressure

The +0.1‰ elevated 56Fe/54Fe ratio of terrestrial basalts relative to chondrites was proposed to be a fingerprint of core-mantle segregation. However, the extent of iron isotopic fractionation between molten metal and silicate under high pressure–temperature conditions is poorly known. Here we show that iron forms chemical bonds of similar strengths in basaltic glasses and iron-rich alloys, even at high pressure. From the measured mean force constants of iron bonds, we calculate an equilibrium iron isotope fractionation between silicate and iron under core formation conditions in Earth of ∼0–0.02‰, which is small relative to the +0.1‰ shift of terrestrial basalts. This result is unaffected by small amounts of nickel and candidate core-forming light elements, as the isotopic shifts associated with such alloying are small. This study suggests that the variability in iron isotopic composition in planetary objects cannot be due to core formation.

Effect of Mn addition on Fe-rich intermetallics morphology and dry sliding wear investigation of hypereutectic Al-17.5%Si alloys

The effect of Manganese addition on the iron-rich intermetallics and wear behavior of Al-17.5%Si hypereutectic alloys has been studied. Dry sliding wear tests have been conducted using a pin-on-disk machine under different normal loads of 18, 51, 74 and 100N and at a constant sliding speed of 0.3m/s. The addition of 1.2wt.% Fe to the base alloy increased the wear rate due to the formation of needle beta intermetallics. Introducing 0.6wt.% Mn to the iron-rich alloy changed the beta intermetallics into the modified alpha phases, and therefore reduced the detrimental effect of iron. Mn addition up to 0.9wt.% to the 1.8Fe alloy did not impede formation of needle-like intermetallic compounds and had no positive effect on the modification of microstructure.

Improvement of thermoelectric power of n-type earth-abundant iron rich alloy by microstructure engineering

Due to the exhaustion of rare metal resources and the hazard of toxic material to the environment, development of cost-effective, nontoxic, and earth-abundant thermoelectric materials has become more urgent. This study introduces a nontoxic, earth abundant n-type iron-based cost-effective Fe–2.3C–Si–5Mn–7V–8Cr thermoelectric material that is prepared by a simple melting method. Significant increase in both electrical conductivity and Seebeck coefficient are achieved by several heat treatment processes to optimize the distribution and grain size of VC, Cr23-xFexC6 typed chromium carbide as well as base matrix. As a result, the power factor of the sample that is normalized at 1150 °C is about 0.75 mWm−1K −2 in maximum value, which is 2.6 times larger than that (0.29 mWm−1K−2) of as-cast sample. The highest ZT value of the sample that is normalized at 1150 °C is 0.028 at 868 K, which is 4.3 times larger than that of as-cast sample (0.0065 at 964 K) in present study, indicating that a proper heat treatment process would remarkably enhance ZT value. This research provides extremely valuable data for the future researches on thermoelectric alloys.

Solidification paths in the iron-rich part of the Fe–Ti–B ternary system

Iron-rich alloys in the Fe–Ti–B system are being studied for their potential as a new generation of lightened steel-matrix composites reinforced by titanium diborides. In this work, the iron-rich corner of the Fe–Ti–B ternary system was investigated at temperatures between 1150 °C and 1400 °C. For this purpose, fourteen key alloys containing up to 5 mass % Ti and B were selected on the basis of preliminary thermodynamic calculations and processed in an induction furnace by melting the starting materials at 1630 °C for 1 h. Two types of experiments were performed: (i) long-duration annealing experiments, involving a liquid phase, performed by the electromagnetic phase separation technique at temperatures between 1175 °C and 1250 °C and (ii) differential thermal analysis of samples during heating up to 1400 °C and cooling with different cooling and heating rates (2, 5 and 10 °C min−1).Samples were characterized by X-ray diffraction, scanning electron microscopy, field electron gun scanning electron microscopy and complementary chemical analysis, combining electron microprobe analysis, inductively coupled plasma and secondary ion mass spectrometry, were performed. On the basis of an analysis of the solidification paths of the fourteen alloys as well as solid/liquid equilibria investigations, a partial liquidus projection in the investigated region was proposed. Moreover, the composition and melting temperature of the γFe–TiB2–Fe2B ternary eutectic alloy are determined with good accuracy. This study is a first step towards an extended experimental work on the iron-rich corner of the Fe–Ti–B ternary system.

Phase Relations, Precious Elements Distribution, and Activities in the Cu-Fe-Pb-As System Saturated with Carbon at 1473 K (1200 °C)

In order to develop a new pyrometallurgical process for the elimination of detrimental arsenic and the recovery of precious elements, such as, silver, gold, and platinum from arsenic-rich copper-lead scraps, the phase relations in the Cu-Fe-Pb-As system saturated with carbon and the distribution of precious elements between the condensed phases generated during the equilibrium at high temperature were investigated. The investigation was carried out by performing a series of laboratory scale experiments using an electrical furnace at 1473 K (1200 °C), followed by the quenching of molten samples taken on the final stage. The samples obtained from the experiments were analyzed using electron probe X-ray micro analysis, inductively couple plasma, and carbon infrared spectrometry techniques. The results were discussed on the basis of the activity coefficient of arsenic, interaction parameters of minor components, and distribution parameters for precious metals in the three equilibrated alloy phases of lead-rich, copper-rich, and iron-rich that coexists in the corresponding miscibility gap. The present results suggest that the recovery of valuable silver and gold into the copper-rich alloy and lead-rich alloy phases and the elimination of arsenic and iron into the iron-rich alloy phase might be feasible.

Optimization of Mechanical and Magnetic Properties in High, Electroplated Co–Fe-Flux Guides

Soft magnetic materials are widely used as flux guides in sensor and actuator applications. Iron-rich binary Co-Fe alloys offer high saturation flux densities Bs up to 2.4 T, which make them suitable as a flux guide material for high field applications. Their fabrication by electrodeposition has been examined to a large extent these last few years. It is well known that the high values of Bs are paid for with high film stress and vulnerability to corrosion. Extensive studies of electroplated films with thicknesses up to 3 μm yielded a better understanding of the influence of deposition techniques and parameters not only on the magnetic properties, but also on the film stress in the deposited layer. For the design of an ultrathin, three-dimensional magnetic field sensor intended for high field applications in very small spaces, flux guides with a thickness of 20 μm are needed. This paper aims at the optimization of the deposition process of these flux guide structures relating to residual film stress, corrosion and investigates the influence on coercivity and saturation flux density.