Thermodynamic studies of oxygen behavior in tantalum-based alloys

Journal Article · Wed Jan 01 04:00:00 EST 1986 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(86)90241-5· OSTI ID:7009732

Lee, J S; Altstetter, C J

A study of equilibrium thermodynamic properties of oxygen in pure tantalum and tantalum alloyed with V, Nb or Mo was made by EMF measurements on solid electrolytic cells over the temperature range 873-1373 K (600-1100/sup 0/C). The solubility of oxygen in pure tantalum in equilibrium with Ta/sub 2/O/sub 5/ was determined to be C/sub s/ = 12.4 exp(-(16kJ/mol)/(RT)) over the experimental temperature range. It was concluded that oxygen obeys Henry's law for concentrations up to the terminal solubility in tantalum for the temperature range 873-1373 K (600-1100/sup 0/C). The oxygen activity coefficient increased with Mo content in Ta-Mo alloys and decreased with V content in Ta-V alloys. The results showed no change in thermodynamic behavior by adding Nb to Ta-O alloys. The positive deviation of the oxygen activity coefficient in Ta-Mo alloys is evidence of a repulsive interaction between molybdenum and oxygen atoms.

• Research Organization: Dept. of Metallurgy and the Materials Research Lab., Univ. of Illinois at Urbana-Champaign, Urbana, IL (US)
• OSTI ID: 7009732
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 34:1; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALLOYS
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ELEMENTS
KINETICS
METALLURGICAL EFFECTS
MOLYBDENUM ALLOYS
NIOBIUM ALLOYS
NONMETALS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION KINETICS
REFRACTORY METAL COMPOUNDS
SOLUBILITY
SOLUTES
TANTALUM ALLOYS
TANTALUM BASE ALLOYS
TANTALUM COMPOUNDS
TANTALUM OXIDES
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
TRANSITION ELEMENT COMPOUNDS
VANADIUM ALLOYS
VERY HIGH TEMPERATURE