共查询到20条相似文献,搜索用时 31 毫秒
1.
A. S. Vusikhis L. I. Leont’ev V. P. Chentsov D. Z. Kudinov E. N. Selivanov 《Steel in Translation》2017,47(1):21-25
The density and surface tension of melts of ferronickel (0–100% Ni) and oxidized nickel ore are measured by the sessile-drop method, as well as the interface tension at their boundary in the temperature range 1550–1750°C. The composition of the nickel ore is as follows: 14.8 wt % Fetot, 7.1 wt % FeO, 13.2 wt % Fe2O3, 1.4 wt % CaO, 16.2 wt % MgO, 54.5 wt % SiO2, 4.8 wt % Al2O3, 1.5 wt % NiO, and 1.2 wt % Cr2O3. In the given temperature range, the density of the alloys varies from 7700 to 6900 kg/m3; the surface tension from 1770 to 1570 mJ/m2; the interface tension from 1650 to 1450 mJ/m2, the density of the oxide melt from 2250 to 1750 kg/m3; and its surface tension from 310 to 290 mJ/m2. The results are in good agreement with literature data. Functional relationships of the density, surface tension, and interphase tension with the melt temperature and composition are derived. The dependence of the alloy density on the temperature and nickel content corresponds to a first-order equation. The temperature dependence of the surface tension and interphase tension is similar, whereas the dependence on the nickel content corresponds to a second-order equation. The density and surface tension of the oxide melt depend linearly on the temperature. The results may be used to describe the formation of metallic phase when carbon monoxide is bubbled into oxide melt. 相似文献
2.
S. N. Anuchkin V. T. Burtsev A. V. Samokhin I. A. Gvozdkov 《Russian Metallurgy (Metally)》2012,2012(3):178-184
The dependence of the degree of sulfur removal on the size factors is studied during the heterophase interaction of refractory compound nanoparticles in a nickel melt. These factors are the time of holding of Al2O3 and TiN nanoparticles in a liquid metal (2?C10 min), the size and number of Al2O3 and TiN nanoparticles, the time of processing of a nickel powder with nanoparticles in a planetary mill (0?300 min), and the sulfur concentration in a Ni-(0.0775?0.1750 wt %) S melt. It is shown that the degree of sulfur removal increases as the average size of Al2O3 nanoparticles decreases from 150 to 35 nm and that of TiN nanoparticles decreases from 2 × 104 to 30 nm. The effect of the number of Al2O3 nanoparticles in a metal on the degree of sulfur removal is considered. A change in the time of processing of a powder mixture in a planetary mill is found to weakly affect the degree of sulfur removal. 相似文献
3.
Thermodynamics of oxygen solutions in Fe-Ni-V melts 总被引:1,自引:1,他引:0
The oxygen solutions in Fe-Ni melts with up to 5% V are analyzed thermodynamically. The results of the works in which the fields of the vanadium-deoxidized oxide phases in iron and nickel were determined are generalized. The thermodynamic model developed for the calculation of the deoxidation of iron-nickel alloys with vanadium is shown to be adequate. The deoxidizing capacity of vanadium decreases insignificantly as the nickel content in the melt increases to 20% and increases substantially as the nickel content increases further. The oxygen solubility curves pass through a minimum, whose position changes from 2.3192% V for pure iron to 0.7669% V for pure nickel. We determined the equilibrium point [V]* between the (Fe, Ni)V2O4 and V2O3 oxide phases for alloys of six compositions at 1873 K. In nickel, [V]* is almost 200 times lower than in iron. The deoxidation of the Fe-40% Ni melt with vanadium is studied experimentally, and the experimental results agree satisfactorily with the calculated data. 相似文献
4.
H. B. Kushkhov R. A. Kardanova V. V. Khasanov I. A. Borukaeva 《Russian Metallurgy (Metally)》2018,2018(8):742-746
The results of high-temperature electrochemical synthesis of holmium–iron triad metal intermetallics in chloride melts are presented. The influence of the current density, the composition of an electrolysis bath, and the synthesis time on the electrolysis processes and the composition of the end product is studied. The electrolysis of the molten KCl–NaCl mixture containing 0.5–2.5 mol % holmium trichloride and 0.1–2.5 mol % nickel (cobalt) dichloride at a current density of 0.5–2.0 A/cm2, a temperature of 973–1073 K, and an electrolysis time of 30–90 min is shown to cause the formation of a cathode deposit in the form of a “metal–salt pear” on a tungsten electrode. This pear consists of a mixture of metallic nickel (cobalt) and HoNi, HoNi5, and HoNi3 (HoCo2, HoCo3, HoCo5, Ho2Co17) intermetallics. The intermetallic compound content in the cathode deposit is found to increase at a constant current density (1.2 A/cm2) and when the holmium chloride content in a melt or the ratio of the holmium chloride concentration to the nickel (cobalt) chloride concentration increases. Only a mixture of holmium–nickel (cobalt) intermetallics can exist in the cathode deposit if the electrolysis bath composition and the electrolysis parameters are controlled. The electrochemical synthesis of holmium–iron intermetallics was performed under galvanostatic conditions in molten KCl–NaCl–HoCl3. Iron ions are introduced in a melt via the anodic dissolution of metallic iron. The results of X-ray diffraction analysis of the electrolysis products demonstrate the fundamental possibility of synthesizing holmium–iron intermetallics. The optimum conditions of electrosynthesis of holmium–iron triad metal intermetallics are determined. 相似文献
5.
An experimental investigation of the rates of oxygen solution in molten cobalt, copper, iron and nickel was carried out using
pure oxygen and a constant-volume Sieverts' method. It was found that the volume of gaseous oxygen which initially reacted
with the inductively stirred metals was strongly dependent on the physical nature of the oxide film which formed during the
first stage of reaction. The initial temperature of the molten iron, cobalt, and nickel was 1600‡C, and for copper was 1250‡C.
For initial oxygen pres-sures above the melt of about one atmosphere both molten iron and copper, which formed liquid surface
oxides, initially absorbed nearly 20 cm3 (STP) O2/cm2 of melt surface area, while molten cobalt and nickel, which formed solid oxides, absorbed about 6 cm3 (STP) 02/cm2 under the same experimental conditions. For approximately 30 s after the initial reaction between these liquid metals and
gaseous oxygen, the oxygen absorption rate was proportional to the square root of the oxygen pressure above the melt, and
pro-portional to the melt surface area, but independent of melt volume. The rate-limiting step for oxygen absorption by liquid
iron, cobalt and copper can be described by dissocia-tive adsorption of oxygen molecules at the gasJoxide interface. After
30 s of reaction, the rate of oxygen absorption became less dependent on the oxygen pressure above the melt. This indicated
that the rate-controlling step was changing from a surface reaction to growth of the oxide layer by cationic diffusion in
the bulk oxide. The oxidation rate of liquid nickel appears to be too complex to be described by models for dissociative ad-sorption
of oxygen molecules at the gasJoxide interface and parabolic growth of the oxide layer. The formation of a thin layer of nickel
oxide which allows oxygen to migrate through cracks or grain boundaries may be responsible for the relatively high oxygen
ab-sorption rate compared to that of liquid cobalt.
Formerly a Graduate Student at The University of Michigan 相似文献
6.
An experimental investigation of the rates of oxygen solution in molten cobalt, copper, iron and nickel was carried out using
pure oxygen and a constant-volume Sieverts’ method. It was found that the volume of gaseous oxygen which initially reacted
with the inductively stirred metals was strongly dependent on the physical nature of the oxide film which formed during the
first stage of reaction. The initial temperature of the molten iron, cobalt, and nickel was 1600°C, and for copper was 1250°C.
For initial oxygen pressures above the melt of about one atmosphere both molten iron and copper, which formed liquid surface
oxides, initially absorbed nearly 20 cm3 (STP) O2/cm2 of melt surface area, while molten cobalt and nickel, which formed solid oxides, absorbed about 6 cm3 (STP) O2/cm2 under the same experimental conditions. For approximately 30 s after the initial reaction between these liquid metals and
gaseous oxygen, the oxygen absorption rate was proportional to the square root of the oxygen pressure above the melt, and
proportional to the melt surface area, but independent of melt volume. The rate-limiting step for oxygen absorption by liquid
iron, cobalt and copper can be described by dissociative adsorption of oxygen molecules at the gas/oxide interface. After
30 s of reaction, the rate of oxygen absorption became less dependent on the oxygen pressure above the melt. This indicated
that the rate-controlling step was changing from a surface reaction to growth of the oxide layer by cationic diffusion in
the bulk oxide. The oxidation rate of liquid nickel appears to be too complex to be described by models for dissociative adsorption
of oxygen molecules at the gas/oxide interface and parabolic growth of the oxide layer. The formation of a thin layer of nickel
oxide which allows oxygen to migrate through cracks or grain boundaries may be responsible for the relatively high oxygen
absorption rate compared to that of liquid cobalt.
R. H. RADZILOWSKI, formerly a Graduate Studient at The University of Michigan 相似文献
7.
V. T. Burtsev S. N. Anuchkin V. V. Sidorov V. E. Rigin 《Russian Metallurgy (Metally)》2013,2013(1):14-17
A thermodynamic computer simulation of the oxidation potential of a gas-melt-ceramic (80 wt% MgO, 20 wt % Al2O3) system under vacuum induction furnace conditions is used to find that the major contribution to this potential at temperatures ranging from 1673 to 2273 K is made by a nickel melt with additives of nickel protoxide. This provides the possibility of oxidative dephosphorization of the metallic melt. The computation of the saturated vapor pressure of phosphorus compounds with the IIA group elements shows that the data obtained for magnesium, calcium, and barium metaphosphates and europium orthophosphate at 1873 K indicate the principal possibility of melt dephosphorization by the evaporation of these compounds under oxidative conditions. 相似文献
8.
In this study the concentration and chemical potential of oxygen in liquid Co-Ni alloys equilibrated with cobalt-nickel aluminate spinel solid solutions and alumina have been determined at 1773, 1823 and 1873K as a function of nickel concentration. The oxygen content of the melt has been measured by suction sampling and inert gas fusion analysis. The corresponding oxygen potential has been determined with the following solid state cell: Mo, Mo+MoO2 | (MgO)ZrO2 | (Co, Ni) melt + AI2O3 + (Co, Ni)O·(1+x)Al2O3, Mo. The effect of nickel on the activity coefficient of oxygen in Co-Ni alloys has been determined. The results for the activity coefficient have been modelled with Wagner's interaction parameters and also the more recent exponential method of St. Pierre et al. at the three temperatures. 相似文献
9.
The interaction of nanoparticles of refractory compounds Al2O3 and TiN with a model nickel melt containing a surfactant (sulfur) is studied. The choice of the type of nanoparticles for
their interaction with the metal at 1873 K and possible versions of sulfur removal from the melt in the form of S2, SO2, and H2S are grounded. A technique for the preparation of an Ni-Al2O3 (TiN) compact and its introduction into the melt is developed. The character of the change in the sulfur content in the metal
after introducing the compact is determined, and the effect of the isothermal holding time of the melt on sulfur removal is
revealed. 相似文献
10.
The interaction of exogenous refractory compound (ZrO2) nanoparticles with sulfur and tin, which are present as surfactants in model nickel melts, is studied. Thermodynamic calculations are performed to consider the versions of removal of sulfur and tin from a melt in the form of S2, SO2, H2S, Sn, and SnO. It is shown that the probability of their removal under melting conditions is low. Their contents is found to decrease when ZrO2 nanoparticles are introduced: the degree of removal is α = 12–18% S in a model Ni–S alloy and 14–20% Sn in a model Ni–Sn alloy. 相似文献
11.
Thermodynamics of the oxygen solutions in Fe-Ni-Ti melts 总被引:1,自引:1,他引:0
A. A. Aleksandrov V. Ya. Dashevskii M. A. Makarov G. S. Sprygin 《Russian Metallurgy (Metally)》2008,(4):271-280
The oxygen solutions in Fe-Ni melts containing up to 3% titanium are analyzed thermodynamically. The results of the works that determined the fields of the oxide phases in iron and nickel deoxidized by titanium are generalized. The proposed calculation model is shown to adequately describe the titanium deoxidation of iron-nickel alloys. The deoxidizing capacity of titanium decreases as the nickel content in the melt increases to 40% and, then, increases sharply as the nickel content increases further. The oxygen solubility curves pass through a minimum, whose position changes from 0.5644% Ti for pure iron to 0.6332% Ti for pure nickel. The points of equilibrium between the TiO2, Ti3O5, and Ti2O3 oxide phases are determined for six alloy compositions at 1873 K. The titanium deoxidation of Fe-40% Ni melts is experimentally studied, and the calculated and experimental results are in good agreement. 相似文献
12.
Specific features and regularities of reactions of titanium carbide alloyed over the sublattice of nonmetals (N, O) with the nickel melt are analyzed. It is established that the partial substitution of carbon in TiC by nitrogen decreases its dissolution rate in nickel and increases the degree of process incongruence (the transfer of carbon into the melt is preferential compared with titanium). The concentration dependence of the dissolution rate of TiCxNz in nickel changes its sign to the opposite one compared with approaching the system to equilibrium. Titanium carbonitride is not recrystallized through the nickel solution as the only phase, and mainly its carbide component is subjected to recrystallization. It is revealed that the partial substitution of carbon in TiC to oxygen increases its dissolution rate in nickel. The dissolution of oxycarbide TiC0.6O0.4 in nickel is accompanied by the gradual loss of its carbon until titanium monoxide is formed and by its further disproportionation. The peculiarity of the interaction mechanism of titanium oxycarbides with the nickel melt is determined by reaction [C] + [O] = CO↑ in the liquid phase. 相似文献
13.
A. S. Vusikhis L. I. Leont’ev V. P. Chentsov D. Z. Kudinov E. N. Selivanov 《Steel in Translation》2017,47(12):772-776
Using the equations of physicochemical hydrodynamics and experimental results regarding the surface and interphase properties of metallic and oxide melts, the conditions in which metallic phase is formed in the bubbling of carbon monoxide through molten oxidized nickel ore are described. The critical dimensions of the gas bubble (Rb.cr) and the metal droplet (rd.cr) moving in oxide melt without change in size are determined in the range 1550–1750°C. It is found that Rb.cr increases slightly from 6.35 × 10–2 m at 1550°C to 6.58 × 10–2 m at 1750°C. With change in the droplet composition and the temperature, rd.cr varies from 2.1 × 10–3 to 2.9 × 10–3 m. The dimensions of the metal droplet formed at a single bubble during the reduction of nickel and iron from oxide melt are determined. As the content of nickel and iron oxides in the melt decreases with increase in the overall CO consumption, the nickel content in the ferronickel droplets falls from 89 to 18%, while the droplet diameter decreases from 1.4 × 10–3 to 8.0 × 10–4 m. The droplet mass falls correspondingly from 9.4 × 10–5 to 1.6 × 10–5 kg. The conditions in which the bubble–droplet system rises through the melt are determined. Over the whole range of temperature and Ni content, the bubble–droplet system begins to rise through the oxide melt when rd/Rb is less than 0.68–0.78. To assess the stability of the bubble–droplet system, with the given bubble and droplet dimensions, the parameters determining their joint motion are calculated. It is found that breakaway of the metal droplet from the bubble is not possible in pyrometallurgical systems. The formation of metal phase as a result of the bubbling of carbon monoxide through the oxide melt is described. In this process, the interaction of the oxide melt with the gas is accompanied by the formation of metal droplets, which become attached to the surface of gas bubbles and move to the surface of the oxide melt. Metal with 80–90% Ni is formed at first. With decrease in the nickel content in the oxide melt, its content in the metal declines to 20%. At the surface of the oxide melt, the metal droplets coalesce. When their diameter is greater than 5 × 10–3 m, they break away from the surface and fall to the bottom. If the falling drop collides with ascending bubble–droplet systems, they may coalesce with it or flow around it. On coalescence, the small droplets will be assimilated and rise to the surface. The breakaway force of the droplet from the bubble significantly exceeds the gravitational force on the droplet. Therefore, the bubble–droplet system is stable for all the size ratios considered. 相似文献
14.
S. N. Anuchkin V. T. Burtsev M. V. Zagumennikov V. V. Sidorov V. E. Rigin 《Russian Metallurgy (Metally)》2010,(5):371-374
The density of melts based on nickel of various grades (i.e., with various oxygen contents) is experimentally studied at 1500–1650°C
and p
Ar = 0.1 MPa, and the effect of alloying elements (Al, Re, W, Mo, Co) on this density is analyzed. As compared to liquid nickel,
the density of a Ni-6% Al melt decreases and that of Ni-(3–7)% Re and Ni-7% Re-(W,Mo,Co) melts increases. The difference between
the molar volume of the melt calculated from the experimental data and using the additivity rule is determined, and the structures
of the melts at 1823 K are found to have a low density. 相似文献
15.
Behavior of Rare-Earth Metals in Vacuum Melting and Directional Solidification of Nickel Superalloys
The interaction of the nickel melt containing REMs (Y, Ce, and La) with the ceramic material of a melting crucible (Al2O3, MgO ? Al2O3, Y2O3) during vacuum melting and with a mold (Al2O3) during directional solidification of has been detected experimentally. The REM concentration in a metal decreases as a result of holding of an REM-containing melt in a ceramic crucible or a mold. This should be taken into account to achieve the optimal required REM content in alloys. 相似文献
16.
The influence of alloying titanium carbonitride TiC0.5N0.5 by transition metals of Groups IV–VI on the mechanism of contact interaction with the nickel melt is studied. It is established that alloying metals exert a strongly destabilizing influence on titanium carbonitride TiC0.5N0.5, simultaneously increasing both its dissolution rate in nickel and the degree of process incongruence (the preferential transition of alloying metal and carbon into the melt). The influence of alloying on the phase stability of titanium carbonitride TiC0.5N0.5 in contact with a nickel melt manifests itself in its dehomogenization or phase separation. The destabilizing effect of alloying additives enhances in a series MeIV–MeV–MeVI parallel with a decrease in their nitrogen affinity. 相似文献
17.
To clarify the mechanism of the formation of LaNi5 by the reduction-diffusion (RD) process, two kinds of experiments were carried out: (1) briquets consisting of La2O3, CaH2, and Ni wires were heated at 1300 K in the RD experiment; and (2) Ni wire was immersed into an Ni-La-Ca melt with a composition
on the Ni-side liquidus surface at 1300 K. On the surface of Ni, LaNi5 grew and the formation of CaNi5 was also observed between the LaNi5 and Ni in the RD reaction; both layers grew in accordance with a parabolic rate law. Even in the reaction of Ni wire with
an Ni-La-Ca ternary melt of low Ca concentrations, CaNi5 initially grew on the nickel surface before LaNi5 was formed, and the Ca in CaNi5 was replaced with La to form LaNi5. The reason for the initial formation of CaNi5 was discussed using molecular orbital calculations. These calculations show that the preferential and temporary formation
of CaNi5 and the final production of LaNi5 can be explained by the electronic structures of Ni alloys containing Ca or La and those of the compounds, CaNi5 and LaNi5, respectively. 相似文献
18.
A new process for electrolytic production of a perfluorinated compound, (CF3)3N, using lanthanum nickel oxide-coated Ni sheet anode in the (CH3)4NF·4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone(PVP). The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000 °C, respectively. The anode performance in the (CH3)4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm−2 in the (CH3)4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3, and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of (CF3)3N (21.4%) was obtained at 20 mA·cm−2 in (CH3)4NF·4.0HF melt using the LaNiO3-coated Ni sheet. 相似文献
19.
The solubility of nickel in slag was determined by equilibrating copper-nickel alloys with alumina-saturated iron silicate
slags in an alumina crucible at 1573 K. The experiments were carried out under controlled oxygen partial pressures in the
range of 10-10 to 10-8 atm by use of suitable CO-CO2 gas mixtures, and at Fe/SiO2 ratio 1.34. The results showed that nickel dissolves in slag both as Ni2+ (nickel oxide) and Ni‡ (nickel metal), and the relation obtained was: (Wt pct Ni in slag) = (ie33-01) The activity coefficient
of nickel oxide (γdgNio) and distribution coefficient of nickel (ANi) is calculated to be 0.375 and 233.3, respectively. γdgNio and ANi are found to be independent of oxygen partial pressures. The presence of alumina increases the solubility of nickel in slags. 相似文献
20.
V. Ya. Kudyakov V. I. Zhuk S. M. Perin V. B. Malkov 《Russian Metallurgy (Metally)》2012,2012(2):128-135
The effect of temperature, the gas phase composition, and the addition of sodium peroxide on the corrosion behavior of a Kh30N45YuT alloy and 20Kh23N18 steel in a eutectic Li2CO3-K2CO3 melt is studied by measuring the corrosion potential and during steplike anode polarization. 相似文献