Thermodynamics of oxygen in solid solution in vanadium and niobium--vanadium alloys

Thesis/Dissertation · Sat Dec 31 23:00:00 EST 1977

DOI:https://doi.org/10.2172/5192877· OSTI ID:5192877

Steckel, Gary Lee ^[1]

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1. Univ. of Illinois, Urbana-Champaign, IL (United States)

A thermodynamic study was made of the vanadium-oxygen and niobium-vanadium-oxygen systems utilizing the solid state galvanic cell technique. Investigations were made with a ThO₂Y₂O₃ electrolyte over the temperature ranges 700 to 1200°C (973 to 1473 K) for the binary system and 650 to 1150°C (923 to 1423 K) for the ternary system. The activity of oxygen in vanadium obeys Henry's law for the temperatures of this investigation for concentrations up to 3.2 at. percent oxygen. For higher concentrations the activity coefficient shows positive deviations from Henry's law. The terminal solubility of oxygen in vanadium was determined. The activity of oxygen in Nb--V alloys obeys Henry's law for the temperatures of this study for oxygen concentrations less than approximately 2 at. percent. For certain Nb/V ratios Henry's law is obeyed for concentrations as high as 6.5 at. percent oxygen. First order entropy and enthalpy interaction coefficients have been determined to describe the effect on the oxygen activity of niobium additions to vanadium-rich alloys with dilute oxygen concentrations. Niobium causes relatively small decreases in the oxygen activity of V-rich alloys and increases the oxygen solubility limit. Vanadium additions to Nb-rich alloys also increases the oxygen solubility and causes substantial decreases in the dilute solution oxygen activities. The change in the thermodynamic properties when molecular oxygen dissolves in vanadium and niobium--vanadium alloys and the equilibrium oxygen pressure over the binary and ternary systems were also determined.

• Research Organization: Univ. of Illinois, Urbana-Champaign, IL (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: EY-76-C-02-1198
• OSTI ID: 5192877
• Report Number(s): COO--1198-1189
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
CRYOGENIC FLUIDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISPERSIONS
ELEMENTS
FLUIDS
HIGH TEMPERATURE
INTERSTITIALS
METALS
MIXTURES
NIOBIUM ALLOYS
NONMETALS
OXYGEN
PHYSICAL PROPERTIES
POINT DEFECTS
SOLID SOLUTIONS
SOLUBILITY
SOLUTIONS
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
TRANSITION ELEMENTS
VANADIUM
VANADIUM ALLOYS
VERY HIGH TEMPERATURE