Oxygen In Metal Research Articles

Thermodynamic laws of the oxygen solubility in liquid metals (Ni, Co, Fe, Mn, Cr) and the formation of oxygen-containing solutions in the alloys based on them

The solubility of oxygen in liquid Ni, Co, Fe, Mn, and Cr metals (Group IV in the periodic table) has been found for the first time. Linear dependences of the oxygen solubility on the standard Gibbs energy for the oxidation reaction of a liquid metal with gaseous oxygen are found. The revealed function of oxygen solubility is of scientific importance and allows one to develop a theory of oxygen solutions in liquid metals and liquid multicomponent metallic compositions and to calculate the energies of mixing of liquid metals with oxygen from ΔGMO° for metal oxidation reactions with allowance for pseudoregular-solution model equations. Using the energies of mixing and metal compositions, we calculated the equilibrium oxygen concentrations in a metal molten pool at the end of oxidation stage of melting 08Kh18N10T steel in an arc furnace. This fact indicates practical importance of the found function of the oxygen solubility in metals.

THERMODYNAMICAL ANALYSIS OF OXYGEN BEHAVIOR DURING LADLE TREATMENT OF HIGH ALLOYED CORROSION RESISTANT STEEL 08Х18Н10Т

The actual activities of oxygen in liquid metal during ladle treatment high alloyed steel have been determined with using oxygen sensors. Activities of components of liquid steel and slag with using pseudosubregular solution for liquid metal and psevdoregular ion solution for liquid slag have been calculated. An equation has been obtained and used to calculate the oxygen activity in equilibrium with components of liquid steel Fe–Cr–Ni–Mn–Si–C–Al–Ti, slag FeO–MnO–CaO–MgO–SiO2–CrO1.5–AlO1.5–TiO2 and gas phases. The study showed that the system “metal–slag–gas phase” at the end of the process of deoxidation of the metal is much closer to equilibrium than at the end of the oxidation process.

Термодинамический анализ условий раскисления и внепечной обработки низкокремнистых марок стали

This article is concerned with analysis and production testing of technological solutions aimed at reducing the consumption of aluminium for steel deoxidation and reducing level of metal contamination by oxide non-metal inclusions, as well as preventing silicon reduction during out-of-furnace treatment. The conditions of low-silicon steel deoxidation and out-of-furnace treatment have been analysed. It has been found that the scope of oxygen activity variation in the converter before tapping increases while the mass fraction of carbon in the metal decreases. For the converter meltings with a mass fraction of carbon over the range 0,05-0,07 % [C] before tapping the real range of variation was 150-300 ppm. The effect of meltings carburizing on aluminium consumption and the degree of aluminium assimilation have been analysed. It has been shown that in fact the same specific consumption of ferromanganese and comparable changes within the metal oxidation change range before tapping (400-1100 ppm) the addition of the carburizer decreases the consumption of aluminium by 0,15 kg/t (in amounts of pure aluminium). The variation interval of assimilation degree of aluminium, consumed for binding the dissolved oxygen in metal and for dissolution in metal has been found. It has been shown that in the melting of low-silicon steel with out- of-furnace treatment but without the use of furnace-ladle unit the rational limit of variation of mass fraction of magnesium oxide variation in the ladle slag is equal to- 6-8 % by weight

Host–guest adsorption behavior of deuterated methane and molecular oxygen in a porous rare-earth metal–organic framework

The yttrium-based metal–organic framework, Y(btc) (btc = 1,3,5-benzenetricarboxylate), shows moderate uptake of methane (0.623 mmol g−1) and molecular oxygen (0.183 mmol g−1) at 1 bar and 308 K. Neutron powder-diffraction data for the guest-free, CD4-, and O2-loaded framework reveal multiple adsorption sites for each gas. Both molecular guests exhibit interactions with the host framework characterised by distances between the framework and guest atoms that range from 2.83 to 4.81 Å, with these distances identifying interaction most commonly between the guest molecule and the carboxylate functional groups of the benzenetricarboxylate bridging ligand of the host.

The abundance of potassium in the Earth’s core

We studied partitioning of potassium (K) between aluminosilicate (adularia, KAlSi3O8) and metals with and without light elements, oxygen and silicon (Fe–O, Fe–Si, and pure Fe metals). We conducted experiments at pressures up to 50GPa, temperatures up to 3500K, and oxygen fugacities (log fO2) between 2.5 and 4.0 log units below the iron-wüstite (IW) buffer using a double-sided laser-heated diamond anvil cell. Our results on pressure, temperature, and compositional effects on partition coefficient of potassium, DK (i.e., the content of potassium in metal [wt%] divided by the content of potassium in silicate [wt%]), revealed that the temperature effect is slightly positive but weaker than that reported previously, whereas the pressure effect is negative. Oxygen in metal increases the potassium content in metal, whereas silicon in metal has the opposite effect. According to the present study on potassium partitioning, we estimated that the amount of potassium in the core is less than 40ppm and that it generates less than 0.17TW heat in the core. The amount of heat generated in the core is very small compared with the heat escaping from the core at the core–mantle boundary (5–15TW).

Behavior of oxygen in the ladle treatment of 08X18H10T high-alloy steel

The actual activity of oxygen in liquid metal is determined by means of sensors during the ladle treatment of 08X18H10T high-alloy steel. The activity of the components of the metallic and oxide solutions is calculated by means of models of a pseudosubregular solution for the liquid metal and a pseudoregular solution for the oxide slag. The corresponding energy parameters were determined in previous research. A formula is derived for the activity of oxygen in equilibrium with the components of Fe-Cr-Ni-Mn-Si-C-Al-Ti liquid steel, eight-component FeO-MnO-CaO-MgO-SiO2-CrO1.5-AlO1.5-TiO2 slag, and the gas phase. It is found that the metal-slag-gas system at the end of reduction is considerably closer to equilibrium than at the end of oxidation. The development of the reduction process is studied in terms of the difference in chemical potentials of the actual and equilibrium oxygen.

Simultaneous Determination of Oxygen, Nitrogen, Hydrogen and Argon in Metals by Pulse Heating and Time of Flight-Mass Spectrometric Method

Simultaneous Determination of Oxygen, Nitrogen, Hydrogen and Argon in Metals by Pulse Heating and Time of Flight-Mass Spectrometric Method

Simulation of Metal/Oxide Interface Mobility: Effects of Mechanical Stresses on Geometrical Singularities

During the last decade, an increasing importance has been given to the feedback of mechanical stresses on the chemical diffusion and, further, on corrosion. Many works point the active role of stresses on the material ageing especially on their negative consequences leading to the damaging of structures. Based on a theoretical study and using numerical tools and experimental results our previous works [1, on stress/diffusion coupling, highlight the strong influence of stress field on the diffusion process. The aim of the present paper is to describe the influence of some particular morphologies of the metal/oxide interface on both diffusion and oxidation process. The oxidation is assumed to be driven by a mass conservation law (Stefan's law) while the diffusion coefficient of oxygen in metal is locally influenced by the stress field. The stability of a waved-shape interface is studied in both cases: simple diffusion and coupled stress/diffusion process. In this purpose we have developed an original numerical model using a virtual metal/oxide interface of a mono-material with oxygen concentration-dependent parameters, which allows to operate easily with any shape of interface and to use simple finite element meshes. Furthermore, in order to underline in a more obvious way the consequences of mechanical stress on the diffusion process, a particular geometry is studied.

Simultaneous determination of oxygen, nitrogen and hydrogen in metals by pulse heating and time of flight mass spectrometric method

The inert gas fusion and infrared absorption and thermal conductivity methods are widely used for quantitative determination of oxygen(O), nitrogen(N) and hydrogen(H) in metals. However, O, N and H cannot be determined simultaneously with this method in most cases and the sensitivity cannot meet the requirement of some new metal materials. Furthermore, there is no equipment or method reported for determination of Argon(Ar) or Helium(He) in metals till now. In this paper, a new method for simultaneous quantitative determination of O, N, H and Ar(or He) in metals has been described in detail, which combined the pulse heating inert gas fusion with time of flight mass spectrometric detection. The whole analyzing process was introduced, including sample retreatment, inert gas fusion, mass spectral line selection, signal acquisition, data processing and calibration. The detection limit, lower quantitative limit and linear range of each element were determined. The accuracy and precision of the new method have also been verified by measurements of several kinds of samples. The results were consistent with that obtained by the traditional method. It has shown that the new method is more sensitive and efficient than the existing method.

Strain-induced interaction of interstitials in IVA group hcp metals

Strain-induced (elastic) interactions of oxygen, nitrogen and carbon atoms in IVA group metals, α-Ti, Zr, and -Hf, are calculated in the framework of the microscopic Krivoglaz–Kanzaki–Khachaturyan theory. The experimental elastic constants, lattice spacing of the host metal, and concentration expansion coefficients are used as the input numerical parameters. The resulting interactions are stronger in α-Ti than in α-Zr and α-Hf. A comparative analysis of interactions in the hcp IVA group metals with those in bcc and fcc solid solutions reveals the crystal structure effect. In general, the strain-induced interactions of O, N, and C in hcp IVA group metals are weaker than in bcc solid solutions and are stronger than in fcc solid solutions.

Examination of the chemical composition of irradiated zirconium based fuel claddings at the metal/oxide interface by TEM

Detailed post-irradiation examinations have been performed at PSI on three fuel rods with differing cladding materials revealing different corrosion behaviour. The rods had been irradiated for 3–5 cycles at Gösgen nuclear power plant (pressurised water reactor), Switzerland. As zirconium corrosion is proceeding at the metal/oxide interface, extended micro-structural analyses were performed by transmission electron microscopy (TEM), expecting to possibly reveal phenomena explaining the varying corrosion resistance. This paper reports on the distribution of oxygen at the metal/oxide interface examined by energy dispersive X-ray spectroscopy (EDS) in TEM, while other micro-structural investigations have been published earlier [1]. In order to get some statistical confidence in the analyses, three neighbouring TEM samples of each cladding variant were studied. The oxygen concentration profiles of the three alloys (i.e. low-tin Zircaloy-4, Zr2.5%Nb and extra low-tin (Sn 0.56%)) both in the oxide and metal close to the metal/oxide interface are compared. The results of the examinations show the composition of the oxide in the vicinity of the interface to be sub-stoichiometric for all three materials, indicating an oxide layer adjacent to the interface, with diffusion-controlled access of oxygen to the metal/oxide interface. The metallic parts show highest oxygen concentrations at the metal/oxide interface which are reduced towards the bulk metal, pointing towards the expected second diffusion-controlled process leading to α-Zr (O). Based on the experimental results values for the diffusion coefficients in the range of 0.8–6.0 × 10 −20 m 2 s −1 are estimated for the oxygen dissolution process, the diffusion coefficient in Zircaloy-4 being six times higher than for the other two less corroding alloys. This finding is in contradiction with the present assumptions about the corrosion mechanism, and confirms the expected but not so far reported diffusion controlled oxidation of different zirconium alloys. It also points towards a corrosion rate that is at least partly governed by the diffusion coefficient of oxygen in metal that is different for different alloys, unlike what has been assumed till present.

Neural network analysis of oxygen in weld metals

The fine acicular ferrite microstructure in the weld metal that results in both good strength and toughness is the result of various oxides that form during solidification. The intent of this paper is to develop a neural networks for the Vickers hardness number as a function of composition and cooling time from 800 to 500°C. The predictive capability of the neural network will then be used to examine the effect of oxygen and its oxides and nitrogen and its nitrides on the Vickers hardness number.

Slip-bearing operation in dense liquid-metal coolants at nuclear power plants

It is presented the results of experimental and numerical investigations in respect to wearing processes occurring in different steel and iron sliding bearing supports of vertical shafts (of pumps and engagements) operating in lead medium, and in the mediums of lead-bismuth and lead-lithium eutectic alloys, if the temperature is less than 510°C, the admixture of thermodynamically active oxygen in molten metal is from 10 up to 10, and there is the solid phase of coolant oxides.

Distribution of phosphorus and oxygen between liquid steel and basic oxygen steelmaking slag

The efficiency of dephosphorisation is governed by the thermodynamic behaviour of phosphorus and oxygen in molten metal, and P2O5 and FeO in slag. The equilibrium distribution of phosphorus and oxygen, for a wide range of chemical compositions simulating the evolution of slag composition during a typical BOF blow, has been experimentally determined. A mathematical model for estimation of the activity coefficients, as a function of the chemical composition, was also attempted.

Determination of oxygen and sulfur thermodynamic activity in molten metals

The paper describes computer analysis of concentration dependence of oxygen activity coefficients fo in binary liquid titanium-base alloys containing ions of copper, nickel, molybdenum, vanadium, zirconium and aluminum. The study covers calculations of oxygen activity coefficient fo and sulphur activity coefficient fs in binary melts of the systems Cu - Fe, Cu - Ni, Cu - Co, Ni - Co, Fe - Ni, Fe - Co as a function of the concentration of metal components.

Computer simulation of internal oxidation and its application to heating‐up experiments for determination of oxygen diffusivities metals—palladium as an example

AbstractInternal oxidation of metal alloys is of great applicational significance as an effective dispersion‐hardening technique, e.g., for Ag, Cu, or Ni alloys, as well as having undesirable side effects to many heat treatment technologies of steels. Wagner's kinetics theory comprises three practically important restrictions: (1) homogeneous initial concentration distribution of the alloying metal M, (2) isobaric, and (3) isothermal processes. The presented new computer model, which is based on an iterative solution of Fick's 2nd law for the inward diffusion of oxygen with internal reaction, overcomes these limitations. Illustrative processes are simulated. Considering the restrictions of Wagner's theory, incomplete isothermal isobaric internal oxidation of dilute homogeneous binary alloys represents an established experimental method for determining the diffusion coefficient of oxygen in the matrix metal: the sought Arrhenius equation is derived by carrying out annealing series at several constant temperatures. The modified simulation‐aided measuring technique of incomplete nonisothermal isobaric internal oxidation, introduced in the present work, reduces the necessary experimental time considerably. Also, as a test of the new computer model, the mathematical evaluation of the data obtained by microscopic analysis of polished cross‐sections is performed by means of this tool. To demonstrate the applicability of the novel experimental technique of temperature‐programmed internal oxidation, the diffusivity of oxygen in palladium is exemplarily measured this way in a Pd‐9.19 at.% Fe alloy and, expressed in cm2/s, found to be DO = 5.32·10−1 · exp(‐18728.27/T). Here, the temperature T ranges from 1073 to 1473 K. This result is compared with literature sources and agrees well with previously published reliable data.

A case study on trace metals in surface sediments and dissolved inorganic nutrients in surface water of Ölüdeniz Lagoon-Mediterranean, Turkey

Hydro-chemical parameters (salinity, temperature, pH, dissolved oxygen, nitrate, silicate and phosphate) in seawater and major trace metals (Al, Fe, Mn, Cr, V, Zn, Pb, Cu) in sediments were evaluated for the assessment of quality of seawater and sediments in very small lagoon in Mediterranean, Ölüdeniz. Enrichment factors for metals in sediment were in the range of 1.62–8.09, comparable to crustal rock composition. For metals, comparison with literature data revealed relatively low metal concentrations for Ölüdeniz sediments. Correlation analyses on the sediment metal data showed strong correlation in between Cr, Fe and Zn. Surface water salinity slightly decreases within the lagoon, indicating that limited fresh waters inflow to the lagoon. In October, the lagoon waters contained very low phosphate concentrations but measurable values of nitrate and silicate, yielding high NO 3 −/PO 4 3− ratios (90). Very low Chlorophyll- a (biomass indicator) concentrations measured in the lagoon suggest the phosphorus limitation of primary productivity.

Materials Interaction at the Nanoscale in High-k Metal Gate Stacks: The Role of Oxygen

We have studied tungsten gated hafnium oxide silicon MOSFETs and show that dissolved oxygen in the tungsten metal can diffuse to the hafnium oxide silicon interface, resulting in interfacial oxide growth and higher mobilities. These results indicate that even small amounts of dissolved oxygen in metal gates is a key issue that can impact device microstructure. We also examine the formation of this oxide and show that there is critical oxygen vacancy concentration in the hafnium oxide, below which interfacial silicon oxide formation will be favorable and above which the interfacial oxide will be unstable.

Solubility and Activity of Oxygen in Pb–Bi Melts

In order to obtain the solubility and activity of oxygen in Pb-Bi melts, the research for oxygen analysis and oxygen partial pressure measurement in a lead-bismuth eutectic alloy (LBE) was performed. The analytical condition of oxygen in low melting metals by an inert gas fusion-infrared absorption method was established using Pb or Bi equilibrated with its corresponding oxide at 973 K as a standard sample for the oxygen analysis. After establishing the analytical condition, oxygen analysis in liquid LBE in equilibrium with solid PbO at various temperatures was done. The temperature dependence of oxygen solubility in liquid LBE was expressed by the following equation, log(C 0 /massppm) = -4.74 x 10 3 /T + 7.06(±0.03) (878 ? T/K ? 1073) Oxygen partial pressure in LBE-(PbO and/or PbO + Bi 2 O 3 ) equilibrium was measured using an oxygen sensor of a zirconia solid electrolyte (ZrO 2 - Y 2 O 3 ), and obtained as a function of temperature as log(p O2 /P°) = 10.96 - 2.259 x 10 4 /T (720? T/K? 1098) log(p O2 /P°) = 2.49 - 1.330 x 10 4 /T (1098? T/K? 1252) From the results, the oxygen potential in LBE at the oxygen unsaturated region was estimated as, RT ln(p O2 /P°)/(J/mol) = -58.59T - 2.510 x 10 5 + 38.29Tlog(Co/massppm) The activity coefficient of oxygen in liquid LBE obtained using Blander's oxygen dissolution model was compared with these experimental data and those of other investigators.

Activation energy of hydrogen, oxygen, and nitrogen diffusion in metals

Significant progress has recently been made in experimental studies of the diffusion of atoms of light elements in metals. In particular, for a number of metals, the diffusion coefficients of tracer atoms of hydrogen (tritium), oxygen, nitrogen, and boron were measured. Previously, such data were available only for carbon. New experimental data enabled us in this work to formulate the problem of developing a theoretical criterion for the reliability of experimental results on the activation energy Q for the interstitial diffusion mechanism. The necessity of formulating such a problem is primarily caused by the fact that the scatter of experimental data on the diffusion of interstitial impurities in metals is often very wide. For example, experimental values of the activation energy Q of hydrogen diffusion in α -Ti are within the range 24‐62 kJ/mol [1]. In this context, in this work, we analyzed experimental data on the diffusion of interstitial atoms in metals that were obtained by reliable methods. It was found that all such data on the activation energy of hydrogen, oxygen, and nitrogen diffusion are consistent with a calculation model [2, 3] based on the theory of elasticity. The calculation accuracy corresponds to the level of a modern precision experiment (on the order of 1%). The corresponding data for carbon and boron were excluded from the analysis. This is because the adequacy of the elastic model of the potential barrier for carbon was not confirmed by the results of measuring the anisotropy of the diffusion coefficients in α -Ti [4, 5]. Data on the diffusion of tracer boron atoms in metals are extremely meager and did not allow us to analyze relationships for boron. Elastic model of the potential barrier. The currently dominant concept of the nature of Q and procedures for calculating Q was formulated in the midtwentieth century [2, 3]. Within this concept, the activation energy Q for the interstitial diffusion mechanism is determined by the elastic energy of crystal strain when an impurity atom is placed at a saddle point; i.e., the larger the diffusant atom, the higher the activation energy Q . The expression for Q has the form [2]