Liquid Copper Alloys Research Articles

Temperature–composition dependence of thermodynamic mixing functions of liquid alloys of copper with rare-earth metals

The composition and temperature dependences of thermodynamic functions of mixing in liquid alloys of copper with rare-earth metals and their variation in the series are considered. It is shown for majority of systems in the series that the most intensive interaction between components is observed in the composition range enriched with copper. The negative deviations of thermodynamic properties of mixing increase with decreasing temperature. The main features of the temperature–composition dependence are explained under the assumption that chemical short-range ordering like a chemical compound forms in the Cu–REM liquid alloys. The temperature–composition dependence of thermodynamic functions of mixing is described in the framework of the ideal associated solution model.

Phase equilibria and thermodynamics of binary copper systems with 3d-metals. VII. Concentration-temperature dependences of the thermodynamic functions of mixing for liquid alloys of copper and transition metals

The CALPHAD method is used for thermodynamic description of binary copper systems with transition metals based on data on the thermodynamic properties of phases and phase transformations. The parameters of models describing the temperature-concentration dependence of thermodynamic functions of mixing are obtained, and the phase diagrams of the systems are calculated. An analysis of the models makes it possible to establish the behavior of the temperature-concentration dependence of the excess thermodynamic functions of mixing for liquid alloys with different types of interaction of the components and to calculate the excess heat capacity. A correlation between the excess heat capacity of liquid alloys and the mixing enthalpy is established.

Enthalpies of Mixing in Liquid Alloys of Copper with Hafnium

Enthalpies of mixing of liquid alloys of copper with hafnium were measured at 1650 K in the concentration range 0 < xHf < 0.50 by high-temperature isoperibolic calorimetry. The experimental data obtained indicates exothermic effects upon alloy formation, which confirm a strong interaction of the components in copper ― hafnium melts.

Enthalpies of liquid–liquid mixing in the systems Cu–Ag, Cu–Au and Ag–Au by using an in-situ mixing device in a high temperature single-unit differential calorimeter

Abstract The enthalpies of mixing of the binary liquid alloys of copper with silver, copper with gold and silver with gold have been re-determined using a new in-situ mixing technique at 1375±2 K. In this paper we report the following analytical expressions for ΔH mix, derived from the experimental results: Cu–Ag: Δ H mix = X Cu X Ag (16,959−7,620 X Ag +4,287 X Ag 2 ) J/mol Cu–Au: Δ H mix = X Cu X Au (−29,506−2,616 X Au +9,360 X Au 2 ) J/mol Ag–Au: Δ H mix = X Ag X Au (−16,803−3,233 X Au +4,525 X Au 2 ) J/mol We note that in all of these systems the enthalpy interaction parameter is described by a nonlinear relation to the composition. These new results are compared with earlier data of Kleppa and Watanabe [O.J. Kleppa, S. Watanabe, Met. Trans. 13B (1982) 391–401] and of Topor and Kleppa [L. Topor, O.J. Kleppa, Met. Trans. 15A (1984) 203–208], obtained by dropping one of the two components into the high-temperature calorimeter from room temperature.

Activity of Phosphorus Oxide in CaO-MnO-SiO2-PO2.5 (-MgO, FetO) Slags.

The CaO–MnO–SiO2–PO2.5(–MgO, FetO) slags were equilibrated with liquid copper alloys in a molybdenum crucible under a flowing CO2/H2 atmosphere in the temperature range of 1573 to 1673 K. The activity coefficient of PO2.5, γPO2.5, and the phosphate capacity, CPO43-=(%PO43-)/PP21/2PO25/4, of the slags were expressed as follows:log γPO2.5 = –2.59 {(%CaO)+0.33(%MnO)+0.55(%MgO)–0.90(%FetO)–0.77(%PO2.5)}/(%SiO2)+1400/T–5.75log CPO43- = 2.60{(%CaO)+0.33(%MnO)+0.55(%MgO)–0.90(%FetO)–0.77(%PO2.5)}/(%SiO2)+40400/T–6.48 The phosphorus distributions between hot metal and the slag were examined, based on the thermodynamic data obtained in the present study. From comparison with the plant data, it was concluded that the thermodynamic data obtained in the present study are satisfactorily applicable to the thermodynamic assessment of hot metal pretreatment with high MnO slag.

Calorimetric research on the heat of formation of liquid alloys of copper with group IIIA and group IVA metals

Using a high-temperature isoperibolic calorimeter of our own design we have determined the concentration dependences of the enthalpy of mixing for alloys of copper with scandium, yttrium, lanthanum, titanium, zirconium, and hafnium. The directly measured enthalpies of dissolution of solid group IVA metals in liquid copper are converted into partial molar enthalpies of mixing, taking into account the data on the high-temperature component of the enthalpies and the enthalpies of fusion of the pure components. The enthalpies of mixing of the liquid alloys are given in tables and equations. The thermodynamic properties are interpreted within the framework of the theory of an ideal associative solution.

Manganese and Phosphorus Equilibria between Liquid Copper and MnO-P2O5 Slag.

The liquid copper alloys containing 0.2-1.0 mass% Mn and 0.03-0.5 mass% P were equilibrated with MnO saturated and unsaturated MnO-P2O5 slags in a molybdenum crucible under a flowing CO2/CO or CO2/H2 atmosphere in the temperature range of 1523 to 1673 K. Manganese-phosphorus and manganese-manganese interaction parameters in liquid copper were found at 1623 K as follows:ePMn= -0.010 eMnP= -0.021 eMnMn= 0.027These values were examined by considering the relationships among oxygen partial pressure, the activities of manganese and phosphorus in liquid copper. The standard free energy changes for the reduction of solid MnO, MnO(s)=Mn+1/2 O2(g), and the dissolution of pure liquid manganese in liquid copper, Mn (l)=Mn, were determined as a function of temperature. The activities of MnO and P2O5 in MnO-P2O5 slags were measured at 1573 K as a function of the composition. The temperature dependence equation of the P2O5 activity was also derived in the MnO saturated condition. On the basis of the present results, examination was done concerning phosphorus and manganese equilibria between hot metal and the MnO-P2O5 slag.

Thermodynamics of Mn-O Interactions in Liquid Copper Alloys and Activities of MnO in MnO-SiO2 Slag.

As a provision for measuring the thermodynamic data of high MnO slag by equilibrating with liquid copper in the temperature range of hot metal pretreatment, thermodynamics of manganese-oxygen interactions in liquid Cu-Mn alloy were investigated. The liquid alloys containing 0.2-1.0mass% Mn were equilibrated with solid MnO in a molybdenum crucible under an argon atmosphere. The following equations for the interaction coefficient (f O Mn ) were obtained for the range of 0.2-1.0 mass% Mn. log f O Mn = -0.8122-1.27[%Mn] + 0.37[%Mn] 2 at 1 573 K log f O Mn = -0.7536 -1,14[%Mn] + 0.33 [%Mn] 2 at 1 623 K log f O Mn = -0.6189-1.07[%Mn] + 0.37 [%Mn] 2 at 1 673 K Using the above values of log f O Mn , the activities and activity coefficients of MnO in MnO-SiO 2 slag were determined at 1 673 K and examined in comparison with the values reported by other investigators.

Heat of formation of liquid copper alloys with 3d-transition metals

A calorimetric method is used to study the enthalpy of mixing in liquid copper alloys with 3d-metals. Results are compared with published information. The change in thermodynamic properties along the 3d-row is not uniform. The regularities obtained are associated with the type of phase diagrams. It is demonstrated that the change in thermodynamic characteristics is determined by features of the electron structure of the components.

Thermochemistry of binary liquid alloys of copper with barium and lanthanide metals (europium, dysprosium and ytterbium)

The heats of mixing of binary liquid alloys of copper with barium, europium and ytterbium in the copper-rich concentration region and the heats of mixing in the Cu-Dy system over the total composition range were measured by isoperibolic calorimetry. The heats of formation increase with increasing atomic number, i.e. in agreement with previous investigations for other Cu-Ln melts. The component interaction energy is found to increase along the row Ba, Eu, Yb, Dy. An apparent variation in the partial mixing enthalpies with atomic size factor which contributes positively to the alloy formation energy is observed. Model calculations of integral enthalpy for the Cu-Ba system based on the atomic size difference factor allow one to estimate the mixing enthalpy in the total concentration region.

Thermodynamic studies of Zn-O interactions in dilute liquid copper alloys

The effect of Zn on the activity coefficient of oxygen in liquid copper at low concentrations has been determined using a solid electrolyte galvanic cell: (—) Pt, W/O (Cu-O-Zn), l//ZrO2-CaO//NiO-Ni/pt (+) The interaction parameter e o (Zn) is found to be −256 at 1100°C, −203 at 1150°C, and −160 at 1200°C. From the results, the enthalpy and entropy interaction parameters have been evaluated. A comparative study of the solute interactions in Cu-O solutions containing Mn, Fe, Co, Ni, and Zn is made in the light of the solution models.

Nature of the white layer in molds for die casting of copper alloys

1. The white layer in the surface of molds for die casting copper alloys consists of a solid solution of copper in α phase. 2. With increasing depth of the white layer the tendency to crazing increases and the mold life decreases. 3. The conditions for formation of the white layer depend on the composition of the steel. The interaction with liquid copper alloys (thickness of the white layer) is smaller in steels with a high chromium content (10–12%). 4. For molds used in die casting copper alloys it is expedient to use corrosionresistant and heat-resistant steel of the 2Kh10VMNF type (or steel 18Kh12VMBFR, GOST 5632-72).

The thermodynamics of dilute liquid cobalt alloys

The published data on the thermodynamics of dilute liquid copper alloys are reviewed. Selected thermodynamic values have been tabulated for binary and ternary alloys. Resume Les auteurs font la cri...

溶銅中の酸素の活量におよぼすコバルトおよび鉄の影響

Electrochemical measurements have been made of the activity of oxygen in liquid copper alloys with small amounts of cobalt and iron in the temperature range of 1100∼1200°C. The galvanic cell used was(This article is not displayable. Please see full text pdf.) Additions of both iron and cobalt lowered markedly the activities of oxygen in liquid copper, and the depression by the addition of iron was about ten times larger than that of cobalt.The interaction parameters ε0(Co) and ε0(Fe) were calculated as follows:(This article is not displayable. Please see full text pdf.)

The thermodynamics of dilute liquid copper alloys

The published data on the thermodynamics of dilute liquid copper alloys are reviewed. Selected thermodynamic values have been tabulated for binary and ternary alloys. Résumé Les auteurs font la critique des données thennodynamiques publiées des alliages liquides de cuivre en région diluée. Des valeurs thermodynamiques sélectionnées ant été classifiées pour les alliages binaires et les alliages ternaires.

The thermodynamics of dilute liquid copper alloys

The published data on the thermodynamics of dilute liquid copper alloys are reviewed. Selected thermodynamic values have been tabulated for binary and ternary alloys. Résumé Les auteurs font la critique des données thennodynamiques publiées des alliages liquides de cuivre en région diluée. Des valeurs thermodynamiques sélectionnées ant été classifiées pour les alliages binaires et les alliages ternaires.

Equilibrium of the Reaction between Steam and Liquid Copper Alloys Containing Nickel or Tin

Equilibrium of the Reaction between Steam and Liquid Copper Alloys Containing Nickel or Tin

銅合金液体のホール係数について

Hall coefficients of liquid copper alloys Cu-Bi, Cu-Sb, Cu-Sn and Cu-In were measured by means of the two-alternating current method in a wide temperature range from 500 to 950°C.No temperature dependence of the Hall coefficient was observed in the liquid state of these alloys. The observed composition dependence of the Hall coefficient for the liquid Cu-Bi alloy was in good agreement with that calculated under the assumption of random mixing of Cu+1 and Bi+5 ions and of free electron approximation. In the other copper alloys, however, deviations from the free electron values R0 calculated under the above simple situation were observed. It is considered that some of the constituent atoms are randomly distributed and others are associated into clusters consisting of several atoms in the liquid states of Cu-In, Cu-Sn and Cu-Sb alloys. Such a cluster is referred to as a pseudo-molecule. A theoretical formula for the Hall coefficients of these liquid alloys was derived as a function of concentration of the pseudo-molecules nR⁄N, the number of localized electrons contributing to the bonding of the pseudo-molecule 2p and an effective volume of pseudo-molecule seen by conduction electrons αΩ0. Using the values of nR⁄N, 2p and αΩ0 obtained from the observations of other physical properties such as heat of mixing, magnetic susceptibility and electric resistivity, the calculated composition dependences of the Hall coefficients of the liquid Cu-In and Cu-Sn alloys were in good agreement with the observed ones. It was shown experimentally that the temperature dependence of the Hall coefficients estimated from the above formula was negligibly small.

The thermodynamic studies of liquid copper alloys by electromotive force method: Part I. The Cu−O, Cu−Fe−O, and Cu−Fe systems

Oxygen activities in liquid Cu−O and Cu−Fe−O alloys were measured in the temperature range 1100° to 1300°C by the solid oxide electrolyte emf method with mixtures of Ni−NiO and Co−CoO as reference electrodes. The Cu−O and Cu−Fe−O alloys were analyzed for iron and/or oxygen content. The activity coefficient of oxygen at infinite dilution in liquid copper was found to be 0.115, 0.195, and 0.286 at 1100°, 1200°, and 1300°C, respectively. The results are compared with previous investigations on the Cu−O system. Based on this comparison, the best equation for the free energy of solution has been suggested. The standard free energy of formation of CoO(s) has been calculated at the experimental temperatures. In the liquid Cu−Fe−O system at 1200°C, a minima in oxygen solubility is reached at 1.1 at. pct Fe in the alloy. The value of interaction coefficient,\( \in _O^{(Fe)} \), is −565 at 1200°C. Iron activities in the liquid Cu−Fe alloys have been calculated at 1100° and 1200°C, and a strong positive deviation from ideality is observed. Results of this study were combined with literature data at 1550°C to obtain the values of\(\Delta \overline G _{Fe}^{xs} \) and\(\Delta \overline S _{Fe}^{xs} \) at infinite dilution in liquid copper.

Thermodynamic studies of liquid copper alloys by electromotive force method: Part II. The Cu−Ni−O and Cu−Ni systems

Oxygen activities in liquid Cu−Ni melts have been measured at 1100°, 1200°, and 1300°C by the solid electrolyte electromotive force method. Addition of nickel lowers the activity coefficient of oxygen in liquid copper. The temperature dependence of\( \in _{\rm O}^{(Ni)} \) can be represented as follows: $$ \in _{\rm O}^{(Ni)} = 17.0 - (3.60 \times 10^4 / T)$$ (1)