Metal Saturation Research Articles

Bose Metals, from Prediction to Realization.

Bose metals are metals made of Cooper pairs, which form at very low temperatures in superconducting films and Josephson junction arrays as an intermediate phase between superconductivity and superinsulation. We predicted the existence of this 2D metallic phase of bosons in the mid 1990s, showing that they arise due to topological quantum effects. The observation of Bose metals in perfectly regular Josephson junction arrays fully confirms our prediction and rules out alternative models based on disorder. Here, we review the basic mechanism leading to Bose metals. The key points are that the relevant vortices in granular superconductors are core-less, mobile XY vortices which can tunnel through the system due to quantum phase slips, that there is no charge-phase commutation relation preventing such vortices from being simultaneously out of condensate with charges, and that out-of-condensate charges and vortices are subject to topological mutual statistics interactions, a quantum effect that dominates at low temperatures. These repulsive mutual statistics interactions are sufficient to increase the energy of the Cooper pairs and lift them out of condensate. The result is a topological ground state in which charge conduction along edges and vortex movement across them organize themselves so as to generate the observed metallic saturation at low temperatures. This state is known today as a bosonic topological insulator.

The REE-Zr-U-Th Minerals of the Maronia Monzodiorite, N. Greece: Implications on the Saturation and Segregation Mechanisms of Critical Metals in Intermediate–Mafic Compositions

This work delves into the presence of REE-Ti-Zr-U-Th minerals, in the mafic–intermediate rocks of the Maronia pluton, Greece, an Oligocene intrusion formed through arc-magmatism during subduction. In Maronia monzodiorite, critical metals are contained in three principal mineral groups, namely, the REE-Ti-Zr, REE-Ca-P, and U-Th assemblages. The REE-Ti-Zr group includes REE-ilmenite, chevkinite-like phases, zirconolite, and baddeleyite. The REE-Ca-P assemblage is represented by allanite-(Ce), monazite-(Ce), and huttonitic monazite-(Ce). The U-Th assemblage comprises thorite–coffinite and uraninite–thorianite solid solutions. The paragenetic sequencing of these minerals offers insights into their formation conditions and correlation with the pluton’s magmatic evolution. In the REE-Ti-Zr group, mineral formation progresses from REE-ilmenite to baddeleyite through chevkinite-like phases and zirconolite under oxidizing conditions. The REE-Ca-P sequence involves allanite-(Ce), followed by monazite-(Ce), late allanite-(Ce), and huttonitic monazite-(Ce). In the U-Th group, earlier thorite–coffinite phases are succeeded by uraninite–thorianite solid solutions, indicating Si-undersaturation at late magmatic stages. Fluctuations in Ca-activity induce alternating formations of allanite-(Ce) and monazite-(Ce). These mineral variations are attributed to early-stage interactions between high-K calc-alkaline and shoshonitic gabbroic melts, influencing critical metal enrichment and mineral speciation. The study’s insights into paragenesis and geological processes offer implications for mineral exploration in analogous geological settings.

The application of cumulating lattice to accelerate diffusion during thermal diffusion chromiing

The creation of coatings on parts with improved corrosion resistance, throughput at low and high temperatures, wear resistance makes it possible to expand the possibilities of using low and medium alloy steels. Traditional methods for creating protective coatings are various types of chemical-thermal treatment and thermal diffusion chromium plating, in particular. In recent decades, attempts have been repeatedly made to increase the efficiency of the process of thermal diffusion saturation of chromium metal, mainly due to complex saturation with vanadium, boron and other elements, as well as the use of external physical influences that accelerate diffusion. Previously, in the works of the authors, it was shown that the introduction of electron-emitter metal powder into the composition of the metal part of the filling ensures the acceleration of diffusion processes during thermal diffusion chromium plating due to the action of an internal emission field. A similar effect is also observed when replacing corundum in the separating part of the filling with powders of solid electrolytes (minerals such as serpentine and scheelite, which are emitters of electrons and anions of the oxygen when heated). An additional enhancement of the internal emission field was noted when cumula-tive nickel and molybdenum lattice were used, however, the effect of the geometric characteristics of these lattice on the magnitude of the thermal emission of electrons and oxygen anions and, as a result, the diffusion acceleration was not established. The paper presents the results of saturation of samples of steel X35CrNi2-3 at a temperature of 1000°C for 24 hours using cumulative lattice that differ in the density of holes per unit area: 20, 10 and 6 holes/cm2. The control of the elemental composition of the diffusion layer was carried out on transverse sections in the direction from the saturated surface to base metal of the sample using a JEOL JSM-6460LV universal scanning (scanning) electron microscope. X-ray phase analysis was performed on an Ultima IV diffractometer, the radiation used was Cu-Kα. The microstructure was studied using an optical microscope Axio Observer D1.m. The microhardness of the coatings was measured using an FM-800 microhardness tester. It has been established that the use of cumulative nickel lattices provides an increase in the depth of the diffusion layer in the base metal by at least 25% and additional alloying coating with a grating metal element with a hole density of 10 pieces/cm2 or more. At a lower density of perforating the lattice, the opposite effect is observed

A Simulation Study of Metallic Mesh Saturation Band in Aliasing Artifact Removal

A Simulation Study of Metallic Mesh Saturation Band in Aliasing Artifact Removal

Evaluation of the Impact of Activated Biochar-Manure Compost Pellet Fertilizer on Volatile Organic Compound Emissions and Heavy Metal Saturation.

For this experiment, pelletized activated biochar made of rice hullsor palm bark with swine manure compost was prepared to demonstrate the significant benefits of applying activated biochar-manure compost pellet fertilizer (ABMCP) inmitigating volatile organic compounds (VOCs), odor emission, and heavy metal saturation. Morphology and surface area analysis indicated that the activated rice hull biochar-manure compost pellet (ARP) had a significantly lower surface area, porous volume, and Fe content the activated palm biochar-manure compost pellet (APP). However, the ARP presented great potential to mitigate VOCs and odorant emissions. Our results indicated that the ARP reduced total reduced sulfur (TRS) and volatile fatty acids (VFAs) emissions by 69% and 93%, respectively. Heavy metals such as Pb, As, and Cd were not detected in the leachates fromthe ARP, APP, and swine manure compost. These results suggest that ABMCP can be a potential adsorbent to control VOCs and odorant emissions andpromote sustainable swine manure management and agricultural application.

Change in carbonate budget and composition during subduction below metal saturation boundary

It is generally accepted that carbonates can be subducted to the mantle depths, where they are reduced with iron metal to produce a diamond. In this work, we found that this is not always the case. The mantle carbonates from inclusions in diamonds show a wide range of cation compositions (Mg, Fe, Ca, Na, and K). Here we studied the reaction kinetics of these carbonates with iron metal at 6–6.5 GPa and 1000–1500 °C. We found that the reduction of carbonate with Fe produces C-bearing species (Fe, Fe-C melt, Fe3C, Fe7C3, C) and wüstite containing Na2O, CaO, and MgO. The reaction rate constants (k = Δx2/2t) are log-linear relative to 1/T and their temperature dependences are determined to bekMgCO3 (m2/s) = 4.37 × 10−3 exp [−251 (kJ/mol)/RT]kCaMg(CO3)2 (m2/s) = 1.48 × 10−3 exp [−264 (kJ/mol)/RT]kCaCO3 (m2/s) = 3.06 × 10−5 exp [−245 (kJ/mol)/RT] andkNa2CO3 (m2/s) = 1.88 × 10−10 exp [−155 (kJ/mol)/RT].According to obtained results at least, 45–70 vol% of carbonates preserve during subduction down to the 660-km discontinuity if no melting occurs. The slab stagnation and warming, subsequent carbonate melting, and infiltration into the mantle saturated with iron metal are accompanied by a reduction of carbonate melt with Fe. The established sequence of reactivity of carbonates: FeCO3 ≥ MgCO3 > CaMg(CO3)2 > CaCO3 ≫ Na2CO3, where K2CO3 does not react at all with iron metal, implies that during reduction carbonate melt with Fe evolves toward alkali-rich. The above conclusions are consistent with the findings of carbonates in inclusions in diamonds from the lower mantle and high concentrations of alkalis, particularly K, in mantle carbonatite melts entrapped by diamonds from kimberlites and placers worldwide.

Metal Saturated Cumulates from Siberia — Lunar Basalt Analogues?

Abstract It is not well known which chemical differentiation pathways basaltic melts will take when they are iron metal saturated. Thermodynamically, the pathway seems predictable. So long as Fe metal is a stable liquidus phase and relative oxygen fugacity (fO2) is not subject to major fluctuations, the activity of FeO (aFeOmelt) is buffered by the iron–wüstite (IW) equilibrium 2Femetal + O2 → 2FeOmelt. Metallic Fe also stabilizes olivine through the equilibrium 2Femetal + O2 + SiO2 melt → Fe2SiO4 olivine. That equilibrium tends to suppress the enrichment in bulk SiO2 when Fe saturated basaltic melts differentiate. We document the differentiation history of tholeiitic cumulates from the Siberian craton that carry up to 30 modal % metallic Fe. Our study is complemented by differentiation experiments at two redox states, one set in Fe metal capsules at 1.6 log units below IW (IW-1.6) and a second set in graphite capsules at IW + 1.5. Iron saturated differentiation pathways do not show enrichments in FeO nor in bulk SiO2 because olivine remains stable along the entire liquid line of descent. By contrast, melts equilibrated at IW + 1.5, that is, outside metallic Fe saturation, crystallize pigeonite as first silicate and follow a normal (terrestrial) differentiation pathway involving marked SiO2 enrichment. The Fe-saturated path duplicates in detail the liquid line of descent we derive for the cumulates. Iron-saturated experiments have limited applicability to the Earth because there are so few terrestrial basalts saturated with metallic Fe; however, they might apply to the Moon. Many lunar basalts appear to have been saturated with an Fe-Ni phase during their emplacement on the lunar surface, and potentially during generation within the lunar mantle.

Influence of technological parameters on nitriding rate in obtaining metal powders by plasma centrifugal spraying

Increase in metal operational properties is ensured by introduction of a certain set and amount of alloying elements into it. These elements include nitrogen, the interest in which is constantly growing. As many works have shown, nitriding with gaseous nitrogen is used, among other things, in plasma-arc remelting. The data is given on metal alloying with nitrogen at the stage of obtaining granules and powders. However, the latter process requires further study. The process of obtaining nitrogen-containing metal microgranules from EP741NP alloy by plasma centrifugal spraying was studied in this work. Metal powders are obtained by melting the end of a rotating workpiece with a stream of ionized gas (mixture of gases). The technology makes it possible to obtain nitrogen-alloyed fine metal powders of multicomponent spherical alloys with a minimum number of satellites that do not differ in size and chemical composition. Investigation of the nitriding rate is of great interest, especially in the production of powder metal. One of the parameters that affect the degree of metal saturation with nitrogen is time spent by liquid melt under nitrogen-containing plasma and crystallization time of the metal drop. The paper presents a technique that allows one to quantify the role of these parameters on the absorption of nitrogen by the metal during powder production. It is known that the kinetic parameters of the nitriding process are determined by the contact area of ​​two metal – gas phases. In the case of obtaining a powder, this parameter depends on the size of a powder speak. In this connection, the paper presents a calculation method that allows estimating the average fractional composition of metal powders depending on a number of technological factors. The obtained values ​​were compared with the data of semi-industrial heats. It is shown that the fractional composition of microgranules depends on the rotation speed and diameter of the workpiece being remelted, the density of the alloy, and the force of surface tension. It was established that with an increase in the rotation frequency of the consumable electrode, it is possible to achieve a decrease in the fineness of metal powders.

The solubility of gold and palladium in magmatic brines: Implications for PGE enrichment in mafic-ultramafic and porphyry environments

We performed experiments to determine the solubility of Au and Pd in magmatic aqueous fluids as a function of oxygen fugacity (ƒO2), temperature (T), pH and total chloride concentration (Cltotal). Experiments were conducted at 800–1000 °C and 200 MPa in an externally-heated rapid-quench Molybdenum-Hafnium Carbide (MHC) cold-seal pressure vessel assembly. We employed a synthetic fluid inclusion (SFI) technique to entrap equilibrated, hydrothermal fluids in response to in situ fracturing of quartz cylinders at experimental run conditions. The solubility of Au and Pd both have positive relationships with ƒO2, temperature, acidity and chlorinity. Concentrated aqueous brines containing 63 wt.% NaCl can dissolve wt.% levels of Au (∼1.2 wt.%) and Pd (∼1.7 wt.%) at metal saturation in relatively oxidized conditions, 1.44 log units above the Ni-NiO oxygen buffer (NNO+1.44), and mildly acidic pH at 900 °C and 200 MPa. Thermodynamic modeling of experimental results suggests that Au is mainly transported as AuCl(aq) at high pH and low Cltotal conditions, whereas HAuCl2(aq) and potentially AuCl2(aq)− predominates at low pH and high Cltotal conditions. Results from thermodynamic modeling also suggest Pd is mobilized in significant contributions by both PdCl2(aq) and PdCl3(aq)− with the latter gaining predominance in response to increasing Cltotal. Calculated fluid/melt partition coefficients for Au and Pd in low-density, magmatic vapors at 1000 °C and 200 MPa suggest that Pd may experience fractionation from Au in porphyry Au-Cu (±Pd, Pt) systems due to the restricted compatibility of Pd in the fluid phase (requiring strongly acidic and substantially high ƒO2 conditions). Moreover, high-density, concentrated aqueous brines facilitate the compatibility of Pd in the fluid phase which may be important with respect to the formation of platinum-group element (PGE)-enriched horizons in layered mafic intrusions (e.g., J-M Reef, Stillwater Complex, U.S.A.). The potential for magmatic, near-neutral pH, high-salinity brines to dissolve significant amounts of Pd as Pd(II)-chloride complexes (∼400 to ∼900 µg/g) well below the NNO buffer suggests that such fluids may be responsible for late-stage hydrothermal remobilization of Pd within mafic-ultramafic igneous environments (e.g., Cu-Ni-PGE footwall deposits and low-sulfide PGE deposits in the Sudbury Igneous Complex, Canada).

Surface energy contributions to the work of infiltration in metal matrix composite processing

The work needed to mechanically drive molten metal into a porous solid preform when producing a composite material by infiltration can significantly exceed the energy change required for thermodynamically reversible infiltration. We measure, by quantitative metallographic analysis of partially infiltrated, particle- or fiber-based non-metallic preforms, the evolution with saturation of the three interfaces present during the process. Results show that irreversible energy losses in the infiltration of alumina preforms by molten copper, aluminium or aluminium-tin alloy cannot be ascribed to the creation of liquid meniscus surface area at intermediate metal saturation. This result agrees with similar observations in soil science and gives experimental confirmation of predictions from a recent simulation of capillarity-dominated metal infiltration [Acta Mater., vol. 210, 2021, 116831].

Nearly Carbon‐Saturated Magma Oceans in Planetary Embryos During Core Formation

AbstractA planetary mantle after core formation has been thought to be highly depleted in carbon due to its strong siderophile behavior. However, the carbon contents in lunar and terrestrial mantles are much greater than experimental predictions; thus, how the carbon contents in terrestrial mantles were established is puzzling and poorly understood. Here, we present high‐pressure experiments on the metal‐silicate partitioning of carbon at 2 GPa and 1923 K in a system containing 0.2 wt% C, which is close to that in enstatite chondrites, and show that a magma ocean made of chondritic materials is nearly saturated with carbon even under metal saturation. The consistency between the solubility of carbon in silicate melts and the carbon contents in lunar and terrestrial mantles also supports a nearly carbon‐saturated magma ocean during core formation and suggests that carbon contents in terrestrial mantles may have been established during the main accretion phase.

Ferric-ferrous iron ratios of experimental majoritic garnet and clinopyroxene as a function of oxygen fugacity

Abstract The oxidation state of iron in upper mantle minerals is widely used to constrain the Earth mantle's oxidation state. Previous studies showed high levels of ferric iron in high-pressure majoritic garnets and pyroxenes despite reducing conditions. To disentangle the effects of pressure and increasing oxygen fugacity on the Fe3+/ΣFe ratios of garnet and clinopyroxene, we performed high-pressure experiments at a pressure of 10 GPa in a 1000-ton Walker-type multi-anvil apparatus at the University of Münster. We synthesized majoritic garnets and clinopyroxenes with a total iron content close to natural mantle values at different oxygen fugacities, ranging from IW+4.7 to metal saturation at IW+0.9. We analyzed the iron oxidation state in garnets with the electron microprobe “flank method.” Furthermore, we investigated the oxidation state of iron in garnets and clinopyroxenes with transmission electron microscopy (TEM) electron energy loss spectroscopy (EELS). Although the flank method measurements are systematically lower than the EELS measurements, Fe3+/ΣFe obtained with both methods agree well within 2σ errors. The “flank method” has the advantage of being much faster and more easily to set up, whereas TEM-EELS has a much higher spatial resolution and can be applied to various non-cubic minerals such as orthopyroxenes and clinopyroxenes. We used our experimental results to compare two geobarometers that contain a term for ferric iron in garnet (Beyer and Frost 2017; Tao et al. 2018) with two geobarometers that do not account for ferric iron (Collerson et al. 2010; Wijbrans et al. 2016). We found that for garnets with low total Fe and Fe3+ (like many natural garnets), the pressures can be calculated without including the ferric iron content.

Investigation of structure and properties of low alloy steel obtained by wire arc additive manufacturing under various fluxes

Wire arc additive manufacturing (WAAM) is vigorously explicating direction of mechanical engineering. When using submerged arc welding (SAW) it is possible to apply low-alloy steels with high efficiency and properties, that will allow to use it for manufacture of details and instrument. Microstructure, hardness, distribution of nonmetallic and chemical composition were investigated for SAW build up walls, in as-deposited condition, by low-alloy wire under fluxes with a different basicity. The characteristics of microstructure fixed by an optical microscopic metallography remain practically constant for all deposited weld metals. It is ferrite – martensite (bainite) structure, which has a high dispersibility. The exploration of hardness has shown formation of the partially quenched top with increased hardness and previous thermo- cyclic treated passes with lower hardness. When depositing SAW insignificant saturation of metal with silicium and manganese and a carbon drop occurs. The distribution of nonmetallics is most favorable for additive manufactured material under neutral and basic fluxes. As a result, a comparative research of fluxes was conducted, allowing to make a choice for additive manufacturing of low-alloy work pieces.

Lactoferrin Metal Saturation-Which Form Is the Best for Neonatal Nutrition?

We evaluated the impact of metal saturation of lactoferrin (with iron and manganese) on population numbers of pathogenic species relevant for neonatal sepsis that commonly originates from the gut due to bacterial translocation. Little attention has been paid to how metal ions bound to the protein affect its activity. Several reference and clinical strains as well as probiotic strains were incubated with different forms of lactoferrin: metal-depleted (apolactoferrin), iron-saturated (hololactoferrin) and manganese-saturated lactoferrin. We also attempted to confirm the observed effects of lactoferrin forms in vivo using rat pups. The observed decrease in population numbers of Gram-negative rods could not be confirmed by quantitative plating—lactoferrin may regulate these populations diversely (e.g., by anti-biofilm activity) and contribute to the inhibition of inflammatory response. We did not see any effect of lactoferrin forms on staphylococci and bifidobacteria. However, we have noted a significant increase of population numbers of Lactobacillus strains upon incubation with manganese-saturated lactoferrin. These results were confirmed in vivo in a rat model. Metal saturation is an underestimated factor regulating lactoferrin activity. Some forms are more potent in the inhibition of pathogenic species while others, such as manganese-saturated lactoferrin, could contribute to the restoration of gut homeostasis.

Warm and oxidizing slabs limit ingassing efficiency of nitrogen to the mantle

Nitrogen is a major and essential component of Earth's atmosphere, yet relative to other volatile elements, there are relatively few experimental constraints on the pathways by which nitrogen cycles between Earth's interior and exterior. We report mineral-melt and mineral-fluid partitioning experiments to constrain the behavior of nitrogen during slab dehydration and sediment melting processes. Experiments reacted rhyolitic melts with silicate and oxide minerals, in the presence of excess aqueous fluid, over temperatures between 725-925°C and pressures between 0.2 and 2.3 GPa. Oxygen fugacity ranged between iron metal saturation (∼NNO-5) to that in excess of primitive arc basalts (∼NNO+2). Our experiments demonstrate that hydrous fluid is the preferred phase for nitrogen over minerals (biotite, K-feldspar, and amphibole) and rhyolitic melts across all conditions explored. Relatively large effects of pressure (Δlog(Dmelt−fluidN)/Δ(GPa/K) = 761 ± 68 (1σ), Δlog(Dbiotite−fluidN)/Δ(GPa/K) = 462 ± 169) and moderate effects of oxygen fugacity (Δlog(Dmelt−fluidN)/ΔNNO = -0.20 ± 0.04, Δlog(Dbiotite−fluidN)/ΔNNO = -0.10 ± 0.04) modulate partitioning of nitrogen. We further document negligible partitioning effects related to mineral composition or Cl content of hydrous fluid. Of the minerals investigated, biotite has the largest affinity for N and should control the retention of N in slabs where present. Application of partitioning data to slab dehydration PT paths highlights the potential for highly incompatible behavior (Dbiotite−fluidN < 0.1) from the slab along warmer and oxidized (NNO+1) subduction geotherms, whereas dehydration along reduced and cooler geotherms will extract moderate amounts of nitrogen (Dbiotite−fluidN > 0.1). We find that slab melting is less effective at extracting N from slabs than fluid loss, at least under oxidized conditions (NNO+1). Ultimately, the conditions under which slabs lose fluid strongly affect the distribution of nitrogen between Earth's interior and exterior.

Coupled Experimental Study and Thermodynamic Modeling of the Fe–Mn–Ti–O System

Thermodynamic optimization of phase diagrams and thermodynamic properties of the FeO–Fe2O3–MnO–Mn2O3–TiO2–Ti2O3 system at 1 atm pressure was performed based on the literature data and new phase diagram data in this study. Isothermal phase diagrams of the system at 1250–1600 °C in air atmosphere were experimentally determined for the first time using the equilibration and quenching method. The liquid phase and complex solid solutions like pseudobrookite, ilmenite and spinel were described using the Modified Quasichemical Model and Compound Energy Formalism, respectively. A set of optimized model parameters of all phases was obtained which reproduces all reliable thermodynamic data and phase equilibria within 3 mol% in composition and ± 25 °C in temperature. The present thermodynamic results can help the prediction of complex thermodynamic data and phase equilibria of the Fe–Mn–Ti–O system at 1 atm total pressure from 25 °C to above the liquidus temperatures over the entire range of composition and $$p_{{O_{2} }}$$ from metallic saturation to 1 atm.

MODELING OF DIFFUSION COATINGS STRUCTURE WITH VANADIUM AND TUNGSTEN IN COMPOSITION-FILLING ENVIRONMENTS

The process of modeling the production of vanadium and tungsten coatings is an effective method of increasing the reliability and durability of machine parts, tools by creating protective layers on the surface of the workpiece, which have a unique set of physico-chemical properties.One of the most effective methods of developing protective layers having high mechanical, physical and chemical characteristics is the diffusion saturation of the surface of the layers using composite powder materials.The formation of protective coatings in composite saturation media occurs under non-stationary temperature conditions. The method of diffusion saturation of the solid phase surface in the active gas medium is based on the analysis of the requirements for the diffusion layer and the method of metal saturation is selected. The rates of chemical processes are determined by kinetic regularities that depend on both temperature and diffusion factors. This method provides high surface quality, is the simplest and most used in laboratory practice, reproduces well in production conditions, and does not require special sophisticated equipment to implement it.

Reduced methane-bearing fluids as a source for diamond

Diamond formation in the Earth has been extensively discussed in recent years on the basis of geochemical analysis of natural materials, high-pressure experimental studies, or theoretical aspects. Here, we demonstrate experimentally for the first time, the spontaneous crystallization of diamond from CH4-rich fluids at pressure, temperature and redox conditions approximating those of the deeper parts of the cratonic lithospheric mantle (5–7 GPa) without using diamond seed crystals or carbides. In these experiments the fluid phase is nearly pure methane, even though the oxygen fugacity was significantly above metal saturation. We propose several previously unidentified mechanisms that may promote diamond formation under such conditions and which may also have implications for the origin of sublithospheric diamonds. These include the hydroxylation of silicate minerals like olivine and pyroxene, H2 incorporation into these phases and the “etching” of graphite by H2 and CH4 and reprecipitation as diamond. This study also serves as a demonstration of our new high-pressure experimental technique for obtaining reduced fluids, which is not only relevant for diamond synthesis, but also for investigating the metasomatic origins of diamond in the upper mantle, which has further implications for the deep carbon cycle.

Coupled Experimental Study and Thermodynamic Modeling of the MgO-MnO-Mn2O3-Ti2O3-TiO2 System

A coupled phase diagram experiment and thermodynamic modeling of the MgO-MnO-Mn2O3-Ti2O3-TiO2 system at 1 bar total pressure is presented. High temperature equilibration and quenching experiments followed by the phase analysis using electron probe microanalysis and X-ray diffraction were performed to obtain complex phase equilibria between solid solutions and liquid phase in air. Low temperature phases during quenching was inevitable in some samples which lead to inaccuracy in the experimental data. The molten oxide phase was described by using the Modified Quasichemical Model, which considers short-range ordering in liquid state, and the Gibbs energies of the extensive solid solutions (pseudobrookite, ilmenite and spinel) were described using the Compound Energy Formalism based on their crystal structures. A set of optimized model parameters of all phases was obtained, which reproduces all the reliable experimental data within experimental error limits from 25 °C to above the liquidus temperatures over the entire range of composition at air atmosphere. The model can also predict the phase equilibria in the range of oxygen partial pressures from metallic saturation to air. The complex phase relationships in the system have been elucidated for the first time and the database of the model parameters can be used with FactSage software to calculate any phase diagrams and thermodynamic properties of the MgO-MnO-Mn2O3-Ti2O3-TiO2 system.

МODELING OBTAINING OF DIFFUSION LAYERS BY USING A COMPOSITE POWDER MATERIALS

The process of modeling the production of alitized, titanium, siliconized, nickeled coatings is an effective method to increase the reliability and durability of machine parts, tools, and tooling due to the creation of protective layers on the surface of the machined parts that have a unique set of physicochemical properties.One of the most efficient methods of the development covering, possessing high mechanical, physic and chemical characteristics is surface metal diffusion saturation using a composite powder materials.The alloys based on copper served the source data for study. The diffusion method of the surface saturation from hard phase in active gas ambience on the basis of analysis of the requirements, presented to copper covering and the way of the metal saturation for defensive covering obtaining has been chosen. This method provides for high surface quality and it is the simplest and most suitable one in laboratory practice being well reproduced in production condition and it does not demand for special complex equipment whileь it’s realizing.