Density and surface tension of a concentrated lead melt in nickel

The influence of a lead impurity on the properties of metallic melts in the composition range that obeys Henry’s law is studied. The formation of the structural and physicochemical properties of real concentrated melts can be traced from changes in the temperature and concentration dependences of structure-sensitive properties, namely, density and surface tension. The surface properties of a solution depend on its volume properties and differ from them in enhancement effect. The lead saturation of the nickel melt is found to be accompanied by a compression effect (decrease in the melt volume), which is enhanced to a certain lead concentration. As this concentration is exceeded, the compression effect weakens because of volume separation and the appearance of an excess lead phase. As the lead content in a nickel base increases, the surface tension decreases, a second phase forms, and the melt undergoes separation.     

Volume and Surface Properties of Antimony-Containing Nickel Melts

A decrease in the detrimental effect of an antimony impurity in nickel is considered using structure-sensitive parameters, namely, density and surface tension. Samples of experimental heats containing 0.01–0.05 wt % Sb are prepared from a preliminarily cast master alloy. Antimony additions are found to increase the density of the nickel melt substantially. A negative density hysteresis appears in the temperature dependences recorded upon cooling. Antimony in the nickel melt is found to have a high surface activity and to decrease its surface tension strongly. When the melt is heated, its surface tension increases, which is accompanied by the passage of antimony into the volume and by changes in the volume and surface solution compositions.     

Surface Properties of Manganese – Tin Liquid Alloys

We used the sessile drop method to study the temperature and concentration dependences of the density and surface tension of melts in the manganese – tin system. The density polytherms are linear dependences which are consistent with those calculated by the additivity rule for the specific volumes of the pure components. The temperature dependences of the surface tension are also linear and their temperature coefficient changes from negative values for tin-rich melts to positive values for melts with high manganese content. The surface tension isotherm is satisfactorily described by the Popel-Pavlov equation. We calculated the composition of the surface layer of the studied melts as a function of the composition of the bulk phase. We have shown that the model for the surface layer of melts in the Mn – Sn system at 1300°C is close to monolayer.     

Density and surface tension of a nickel melt deoxidized with rare- and alkaline-earth metals

The temperature dependences of the density and surface tension of a nickel melt deoxidized with lanthanum, cerium, calcium, and magnesium are studied. The dependences exhibit both a positive and negative hysteresis of the properties. Lanthanum added to the nickel melt changes the curves and the validity coefficients of their linear or polynomial approximation.     

Volume and surface properties of nickel melts containing bismuth impurity determined from the density and the surface tension

The physicochemical and the structural properties of the nickel-based melts with a low (impurity) bismuth content, which, like lead, is one the most harmful impurities in cast high-temperature nickel-based superalloys, are studied using the surface tension and the density. It is found that the surface tension increases as the bismuth impurity content varies from zero to 0.05 wt %, which corresponds to transition of excess substance from the surface into the volume.     

Effect of exogenous refractory nanophases on the structural properties of nickel melts

The surface tension and density of nickel and Ni-S melts containing Al₂O₃ and TiN refractory-phase nanoparticles (RPNPs) are studied by the sessile drop method using a digital camera and computer processing of images. The dependences of the structural properties of Ni, Ni-(Al₂O₃,TiN), Ni-S, and Ni-S-(Al₂O₃,TiN) melts on temperature and the type and size of RPNPs are determined. It is found that the surface tension decreases with increasing temperature, the temperature dependence of the surface tension is inverted, the degree of loosening in the Ni-S-(Al₂O₃,TiN) melts decreases, and Ni-S-RPNP ensembles affect the melt structure.     

Thermodynamic Simulation of the A<Superscript>III</Superscript>–B<Superscript>V</Superscript> Semiconductor Melts

The equilibrium compositions and the thermodynamic characteristics of binary Ga–Sb, Al–Sb, and In–Sb melts are studied by a thermodynamic simulation using the TERRA software package over wide temperature and composition ranges. The temperature dependences of the partial pressures of the components of the gas phase forming above the III–V (III = Ga, In; V = Sb) semiconductor melts are investigated. The concentration dependences of the component activities and the partial and integral characteristics of melt mixing are obtained. All melts under study are shown to exhibit large negative deviations from Raoult’s law, which is caused by the presence of associates and indicates a strong interaction between the melt components. The temperature dependences of the logarithms and the partial pressures of the gas phase components are obtained. These dependences are shown to be linear for the components of the gas phase forming over the Ga–Sb, Al–Sb, and In–Sb melts.     

Effect of slag inclusions on the density and the surface tension of liquid 32G2 and 32G1 steels

The density and the surface tension of liquid 32G2 and 32G1 steels are experimentally studied. Samples are cut from oil-and-gas pipes having different degrees of imperfection. The experimental results are used to find the effect of the defects detected by magnetic-powder and ultrasonic inspection methods on the temperature dependences of the density and the surface tension of liquid 32G2 and 32G1 steels. The results obtained are interpreted in terms of the concepts of a microheterogeneous structure of metallic melts. Microheterogeneities are irreversibly destroyed when the liquid 32G2 steel is heated to 1700°C and the 32G1 steel, to 1750°C.     

Measurement of viscosity,density and surface tension of metal melts

A modified procedure for measuring viscosity, surface tension and density of metallic melts, using a gas bubble viscosimeter, is presented. The principle of measurement is based on the relation between rate of ascent of a gas bubble in the melt and the melt viscosity. The rate of bubble ascent is determined by registering the moment of detachment by pressure measurement in the lance and the moment of arrival of the bubble at the melt surface by video film and an image processing system. The procedure is tested and the limits of its application are determined by comparative measurements on reference metals. After tests on reference metals, measurements are taken of the viscosity, density and surface tension of Al-Cu alloys in the temperature range 960 – 1465 K with copper contents of 12.23 to 58.5%. The relationships between these values and temperature and composition of the melt are investigated, and corresponding approximation formulae derived.     

Interaction of exogenous refractory nanophases with antimony dissolved in liquid iron

The heterophase interaction of Al₂O₃ refractory nanoparticles with a surfactant impurity (antimony) in the Fe–Sb (0.095 wt %)–O (0.008 wt %) system is studied. It is shown that the introduction of 0.06–0.18 wt % Al₂O₃ nanoparticles (25–83 nm) into a melt during isothermal holding for up to 1200 s leads to a decrease in the antimony content: the maximum degree of antimony removal is 26 rel %. The sessile drop method is used to investigate the surface tension and the density of Fe, Fe–Sb, and Fe–Sb–Al₂O₃ melts. The polytherms of the surface tension of these melts have a linear character, the removal of antimony from the Fe–Sb–Al₂O₃ melts depends on the time of melting in a vacuum induction furnace, and the experimental results obtained reveal the kinetic laws of the structure formation in the surface layers of the melts. The determined melt densities demonstrate that the introduction of antimony into the Fe–O melt causes an increase in its compression by 47 rel %. The structure of the Fe–Sb–O melt after the introduction of Al₂O₃ nanoparticles depends on the time of melting in a vacuum induction furnace.     

Polytherms of the physical properties of metallic melts

The temperature dependence of the kinematic viscosity, electrical resistivity, surface tension, and density of liquid steels and alloys on heating and subsequent cooling is analyzed. On that basis, the polytherms of the physical properties of steels and alloys are systematized. On heating to certain critical temperatures, changes occur in the structure of the melt. Consequently, the cooling polytherms take a form more closely resembling the equilibrium classical laws and do not match the heating polytherms. Branching or hysteresis of the temperature dependences is only irreversible on heating to critical temperatures. Otherwise, partial or complete return to the primary melt structure is possible. That affects the degree of hysteresis of the polytherms. The degree of hysteresis and the data regarding the properties provide qualitative information regarding the transition of the melt structure from the equilibrium to the microhomogeneous state. The uniformity of the distribution of atoms of the alloying elements in microgroupings or clusters indicates the equilibrium of the structure, while the uniformity of the distribution of clusters that differ in structure over the melt volume reflects structural microhomogeneity. Data on the properties of multicomponent metals indicate that, after melting, the variation in melt properties on isothermal holding takes the form of familiar damping oscillations. With increase in temperature, the damping becomes aperiodic, and the relaxation time declines. The processes responsible for the isothermal variation in melt properties occur at the microscopic level. Nonequilibrium industrial metal usually contains inclusions inherited from the initial materials, such as insoluble graphite particles in the cast iron or associations and aggregations of carbide and nitride type. The melt takes a long time to reach equilibrium—usually longer than the time for diffusional mixing of the atoms within the nonequilibrium regions. With more complex chemistry and structure of the solid metal, the distance of the melt from equilibrium will be greater. In this system, new correlations are formed and broken more intensely. Cooperative interactions of the new spatial and time structures with those inherited from the initial materials occur here, as indicated by oscillating behavior of the properties of the metallic melts. Information regarding the state of the melt before solidification permits scientific analysis of the melting points and melting times of the steels and alloys. Such preparation of the melt affects its supercooling, its solidification rate, the formation of hardening phases and eutectics, the segregation of the elements, the dendrite and zonal; structure of the castings, and the overall product quality and production efficiency.     

Formation of metallic phase on reducing-gas injection in multicomponent oxide melt. Part 2. Density and surface properties

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.     

Al2O3和Cr2O3对自蔓延冶金法制备 CuCr合金冶炼渣性能的影响

自蔓延冶金法制备CuCr合金时,合金中的Al₂O₃和Cr₂O₃夹杂物会在熔渣精炼过程中被冶炼渣溶解,改变熔渣成分,从而影响冶炼渣的熔点、黏度、密度和表面张力等性能,给精炼过程带来不利影响.使用熔体物性测定仪针对Al₂O₃和Cr₂O₃含量变化对冶炼渣的性能影响规律进行了研究,结果表明:Al₂O₃和Cr₂O₃含量的增加均可以提高熔渣的黏度、凝固温度和表面张力,Cr₂O₃对黏度和表面张力的影响较大,Al₂O₃对凝固温度的影响较大;Al₂O₃使熔体密度上升,Cr₂O₃使熔体密度先上升后下降.      

Interaction of refractory compound nanoparticles with a surfactant in a nickel melt: II. Surface tension and density

The surface tension and density of Ni-S melts with Al₂O₃ or TiN nanoparticles are studied by the sessile drop method using a digital photographic camera and computer processing of images with special-purpose computer programs. The dependences of the surface tension and density of (Ni-S) + (Al₂O₃, TiN) melts on the temperature and the type of introduced refractory compound nanoparticles are determined, and the inversion of the temperature dependence of the surface tension of the Ni-S-Al₂O₃ system is detected. Metallographic analysis of polished sections demonstrates the presence of aluminum, nickel, and sulfur in nonmetallic inclusions at grain boundaries in the first series of experiments and the presence of titanium, nickel, and sulfur in globular nonmetallic inclusions in the second series of experiments.     

Surface effects and flow conditions in small volume melts with varying sulphur content

The surface effects and flow behaviour in melts with a volume of a few cubic millimetres were investigated using 1 mm thick X5CrNi18‐9 (AISI 304) stainless steel strips after partial remelting by a TIG (tungsten inert gas) burner. In the industrially produced material the S mass content was varied between 20 and 100 ppm. The surface excess of sulphur indicates that the surface saturation was not achieved compared to the values in the Fe‐S system. The thickness of the layer with high sulphur enrichment depends on the S activity and varied between approximately 260 and 460 nm and achieves the bulk S content at a distance of approximately 1.2 μm from the surface. This layer is noticeably thinner than the diffusion boundary layer and considerably thinner than the flow boundary layer. The topography of the rapidly solidified liquid pool makes it possible, taking previously estimated temperature coefficients of surface tension into account, to explain the flow behaviour in the melt with regard to the S content and to the temperature gradients. The results obtained indicate that the shearing force caused by surface tension gradients (Marangoni effect) controls the flow conditions in small volume melts.     

Effect of the mechanical activation of Ln2O3 Oxides (with Ln = Gd, Dy, Ho, and Lu) on the surface tension and density of borate melts

Effect of the mechanical activation of Gd₂O₃, Dy₂O₃, Ho₂O₃, and Lu₂O₃ oxides on surface tension ?? and density ?? of borate melts is studied. Linear temperature dependences of ?? and ?? are found, and the temperature coefficients are calculated. The dependence of ?? on the lanthanide number in the periodic table is found and exhibits nonmonotonic behavior of the melts. The effect of mechanical activation on ?? and ?? is explained by the formation of complex lanthanide ions, which have uniform geometry in the borate melts.     

Surface Phenomena and Interfacial Interaction at the Glass–Liquid Tin–Gas Phase Interface

We used the sessile drop method to study the temperature dependences of the density and surface tension of tin and liquid glass. We have studied the effect of the composition of the gas phase on the surface tension of the glass. We used the method of adjoining drops to determine the temperature dependence of the interfacial tension at the glass horbar; tin melt boundary. We have studied the effect of silicon, aluminum, iron, nickel, and manganese on the interfacial tension in the glass tin system. We have shown that in this system, these additives are not interface-active.     

Physicochemical properties of matte-slag melts taken from vanyukov’s furnace for copper extraction

The properties of liquid slag and matte were studied in the autogeneous extraction of copper which occurs in the Vanyukov’s furnace, applied in the Balkhash copper-smelting plant (Balkhash Group of Mining and Metallurgical Enterprises, Kazakhstan). The density and surface tension of the melts were measured using the maximum-bubble pressure method, and the viscosity of the melts was measured by the rotational method. These properties were determined in the temperature interval from 1350 °C to 1550 °C. The temperature coefficients of the surface tension, density, and viscosity were determined, and the technological significance of results obtained is considered.     

Determination of the Composition of the Surface Layer of Binary Metal Alloys

We have analyzed the effect of various parameters (surface tensions of the components, molar volumes of the components and the solution, compression and depression in alloy formation, activity coefficients of the components in the melt) on the shape of the surface tension isotherm as a function of the surface layer composition. We compare the analysis results with experimental data. We propose a method for estimating the composition of the surface layer based on a model assuming an additive variation in the surface tension of the solution as a function of the composition of the surface layer. We have calculated the concentration of the surface-active component in the surface layer of melts in the systems Ge - Sn, Ge - Pb, and Ge - Bi.__________Translated from Poroshkovaya Metallurgiya, Nos. 1–2(441), pp. 60–67, January–February, 2005.     

NdF_3-LiF-Nd_2O_3体系表面张力数学模型的研究

用拉筒法研究了低NdF3 浓度下NdF3-LiF体系的表面张力 .采用二因子二次回归正交设计 ,得出表面张力 (σ)与NdF3 含量 (C)、温度 (t)的回归方程 ,讨论了NdF3含量、温度对表面张力的影响 ,并考察了加入Nd2 O3 对体系表面张力的影响