Phase equilibria of the MgO-Cu2O-CuO system

M. Paranthaman; K. A. David; T. B. Lindemer

doi:10.1016/S0025-5408(96)00184-5

Phase equilibria of the MgO-Cu₂O-CuO system

M. Paranthaman, K. A. David, T. B. Lindemer

Nanomaterials Chemistry Group

Research output: Contribution to journal › Article › peer-review

34 Scopus citations

Abstract

Phase equilibria of the MgO-Cu₂O-CuO system have been determined in air at temperatures ranging from 850 to 1100°C. The starting compositions ranged from 0 to 100% Mg in (Mg_1-xCu_x)O. CuO was quite soluble in MgO. The solubility of CuO in MgO at 850°C was about 9% and at 1050°C was about 20%. The only known ternary Guggenite phase had a composition of Cu₂MgO₃. The Guggenite phase exists in three forms, namely, Guggenite A (G_A, orthorhombic, space group Pmmn(59)), Guggenite B (G_B, orthorhombic, space group I(0)), and Guggenite X (G_x, monoclinic). Guggenite A was obtained as a single phase in air at x_CuO = 67% (i.e., 67% CuO and 33% MgO) and 1000°C. It undergoes a phase transition to the Guggenite X phase when it is heated above 1050°C. The Guggenite B phase was obtained in a mixture at x_CuO = 75% and at temperatures above 1050°C. MgO was not found to be soluble in CuO. For samples with x_CuO ≥ 67%, the Guggenite A phase coexisted with tenorite (CuO, monoclinic) at temperatures ≤ 1000°C and above 1021°C, it was in equilibrium with cuprite (Cu₂O, cubic). For CuO compositions between 20% and 67%, a mixture of Guggenite A phase and the periclase phase (MgO, cubic) was obtained at temperatures ≤ 1000°C. The decomposition of Cu₂MgO₃ (Guggenite A) phase was determined at several oxygen partial pressures and the Gibbs free energy of formation of this phase Was also Calculated.

Original language	English
Pages (from-to)	165-173
Number of pages	9
Journal	Materials Research Bulletin
Volume	32
Issue number	2
DOIs	https://doi.org/10.1016/S0025-5408(96)00184-5
State	Published - Feb 1997

Funding

We thankJ . Brynestada ndD .M. Kroegerf or helpfuld iscussionsW. e alsot hankD .B. Beach for constante ncouragemenTt.h e researchw as sponsoredb y the Division of Materials SciencesO, ffke of Basic EnergyS ciencesa ndO ffice of EnergyE fficiency andR enewable Energy, Office of Utility Technology-SuperconductivitPyr ogram. The researchw as performeda t the Oak Ridge NationalL aboratory,O RNL, managedb y LockheedM artin Energy ResearchC orporationf or the U. S. Departmenot f Energy underc ontract# DE-AC05-960R22464.

Funders	Funder number
Division of Materials SciencesO
Office of Utility Technology-SuperconductivitPyr
ffke of Basic EnergyS ciencesa ndO ffice of EnergyE fficiency andR enewable Energy

Keywords

A. oxides
B. chemical synthesis
C. X-ray diffraction
C. thermogravimetric analysis
D. phase equilibria

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10.1016/S0025-5408(96)00184-5

Cite this

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title = "Phase equilibria of the MgO-Cu2O-CuO system",

abstract = "Phase equilibria of the MgO-Cu2O-CuO system have been determined in air at temperatures ranging from 850 to 1100°C. The starting compositions ranged from 0 to 100% Mg in (Mg1-xCux)O. CuO was quite soluble in MgO. The solubility of CuO in MgO at 850°C was about 9% and at 1050°C was about 20%. The only known ternary Guggenite phase had a composition of Cu2MgO3. The Guggenite phase exists in three forms, namely, Guggenite A (GA, orthorhombic, space group Pmmn(59)), Guggenite B (GB, orthorhombic, space group I(0)), and Guggenite X (Gx, monoclinic). Guggenite A was obtained as a single phase in air at xCuO = 67% (i.e., 67% CuO and 33% MgO) and 1000°C. It undergoes a phase transition to the Guggenite X phase when it is heated above 1050°C. The Guggenite B phase was obtained in a mixture at xCuO = 75% and at temperatures above 1050°C. MgO was not found to be soluble in CuO. For samples with xCuO ≥ 67%, the Guggenite A phase coexisted with tenorite (CuO, monoclinic) at temperatures ≤ 1000°C and above 1021°C, it was in equilibrium with cuprite (Cu2O, cubic). For CuO compositions between 20% and 67%, a mixture of Guggenite A phase and the periclase phase (MgO, cubic) was obtained at temperatures ≤ 1000°C. The decomposition of Cu2MgO3 (Guggenite A) phase was determined at several oxygen partial pressures and the Gibbs free energy of formation of this phase Was also Calculated.",

keywords = "A. oxides, B. chemical synthesis, C. X-ray diffraction, C. thermogravimetric analysis, D. phase equilibria",

author = "M. Paranthaman and David, {K. A.} and Lindemer, {T. B.}",

year = "1997",

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doi = "10.1016/S0025-5408(96)00184-5",

language = "English",

volume = "32",

pages = "165--173",

journal = "Materials Research Bulletin",

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publisher = "Elsevier",

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TY - JOUR

T1 - Phase equilibria of the MgO-Cu2O-CuO system

AU - Paranthaman, M.

AU - David, K. A.

AU - Lindemer, T. B.

PY - 1997/2

Y1 - 1997/2

N2 - Phase equilibria of the MgO-Cu2O-CuO system have been determined in air at temperatures ranging from 850 to 1100°C. The starting compositions ranged from 0 to 100% Mg in (Mg1-xCux)O. CuO was quite soluble in MgO. The solubility of CuO in MgO at 850°C was about 9% and at 1050°C was about 20%. The only known ternary Guggenite phase had a composition of Cu2MgO3. The Guggenite phase exists in three forms, namely, Guggenite A (GA, orthorhombic, space group Pmmn(59)), Guggenite B (GB, orthorhombic, space group I(0)), and Guggenite X (Gx, monoclinic). Guggenite A was obtained as a single phase in air at xCuO = 67% (i.e., 67% CuO and 33% MgO) and 1000°C. It undergoes a phase transition to the Guggenite X phase when it is heated above 1050°C. The Guggenite B phase was obtained in a mixture at xCuO = 75% and at temperatures above 1050°C. MgO was not found to be soluble in CuO. For samples with xCuO ≥ 67%, the Guggenite A phase coexisted with tenorite (CuO, monoclinic) at temperatures ≤ 1000°C and above 1021°C, it was in equilibrium with cuprite (Cu2O, cubic). For CuO compositions between 20% and 67%, a mixture of Guggenite A phase and the periclase phase (MgO, cubic) was obtained at temperatures ≤ 1000°C. The decomposition of Cu2MgO3 (Guggenite A) phase was determined at several oxygen partial pressures and the Gibbs free energy of formation of this phase Was also Calculated.

AB - Phase equilibria of the MgO-Cu2O-CuO system have been determined in air at temperatures ranging from 850 to 1100°C. The starting compositions ranged from 0 to 100% Mg in (Mg1-xCux)O. CuO was quite soluble in MgO. The solubility of CuO in MgO at 850°C was about 9% and at 1050°C was about 20%. The only known ternary Guggenite phase had a composition of Cu2MgO3. The Guggenite phase exists in three forms, namely, Guggenite A (GA, orthorhombic, space group Pmmn(59)), Guggenite B (GB, orthorhombic, space group I(0)), and Guggenite X (Gx, monoclinic). Guggenite A was obtained as a single phase in air at xCuO = 67% (i.e., 67% CuO and 33% MgO) and 1000°C. It undergoes a phase transition to the Guggenite X phase when it is heated above 1050°C. The Guggenite B phase was obtained in a mixture at xCuO = 75% and at temperatures above 1050°C. MgO was not found to be soluble in CuO. For samples with xCuO ≥ 67%, the Guggenite A phase coexisted with tenorite (CuO, monoclinic) at temperatures ≤ 1000°C and above 1021°C, it was in equilibrium with cuprite (Cu2O, cubic). For CuO compositions between 20% and 67%, a mixture of Guggenite A phase and the periclase phase (MgO, cubic) was obtained at temperatures ≤ 1000°C. The decomposition of Cu2MgO3 (Guggenite A) phase was determined at several oxygen partial pressures and the Gibbs free energy of formation of this phase Was also Calculated.

KW - A. oxides

KW - B. chemical synthesis

KW - C. X-ray diffraction

KW - C. thermogravimetric analysis

KW - D. phase equilibria

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U2 - 10.1016/S0025-5408(96)00184-5

DO - 10.1016/S0025-5408(96)00184-5

M3 - Article

AN - SCOPUS:0031071511

SN - 0025-5408

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EP - 173

JO - Materials Research Bulletin

JF - Materials Research Bulletin

IS - 2

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