Study of metal--oxygen solid solutions utilizing solid electrolytic cells

Thesis/Dissertation · Sun Oct 01 04:00:00 EDT 1978

DOI:https://doi.org/10.2172/6783497· OSTI ID:6783497

Lauf, Robert John ^[1]

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

A study was made of the thermodynamic and kinetic behavior of oxygen in a number of Group V metals and alloys. Investigations were made with a ThO₂Y₂O₃ electrolyte over the temperature range of 600 to 1150°to 1423°K). The activity of oxygen in three Nb--Ta alloys (nominally 25, 50, and 75 at. % Ta) was found to obey Henry's Law up to the solubility limit in each alloy. The standard entropy and enthalpy of solution of oxygen in the three Nb--Ta alloys were intermediate between those for pure niobium and pure tantalum, and varied almost linearly with Nb : Ta content. The diffusion coefficient of oxygen was measured in niobium and vanadium, and the values were found to be in excellent agreement with literature values obtained by a variety of techniques. The diffusion coefficient of oxygen in each of several dilute substitutional niobium alloys was measured and compared to the diffusion coefficient in pure niobium. The addition of 1 to 5% substitutional solutes resulted in as much as an order-of-magnitude decrease in the oxygen diffusivity. This decrease is believed to be due to trapping of oxygen by substitutional solute atoms. The substitutional-oxygen binding or ''trap'' energies (in eV) for several substitutional solutes in niobium were determined to be: Ta: 0.3 ± 0.1; V: 0.55 ± 0.05; Ti: 0.7 ± 0.1; Zr: 0.7 ± 0.05. The trap energy is rationalized as being the sum of a chemical interaction and an elastic interaction. 27 figures, 9 tables.

• Research Organization: Univ. of Illinois, Urbana-Champaign, IL (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: EY-76-C-02-1198
• OSTI ID: 6783497
• Report Number(s): COO--1198-1216
• 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
ACTINIDE COMPOUNDS
ALLOY SYSTEMS
ALLOYS
BINARY ALLOY SYSTEMS
CHALCOGENIDES
CRYOGENIC FLUIDS
DIFFUSION
DILUTE ALLOYS
DISPERSIONS
ELEMENTS
ENTHALPY
ENTROPY
FLUIDS
HIGH TEMPERATURE
METALS
MIXTURES
NIOBIUM
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PERMEABILITY
PHYSICAL PROPERTIES
REFRACTORY METALS
SOLID SOLUTIONS
SOLUBILITY
SOLUTION HEAT
SOLUTIONS
SOLVENT PROPERTIES
TANTALUM ALLOYS
THERMODYNAMIC PROPERTIES
THORIUM COMPOUNDS
THORIUM OXIDES
TITANIUM ADDITIONS
TITANIUM ALLOYS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VANADIUM
VANADIUM ALLOYS
VERY HIGH TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
ZIRCONIUM ADDITIONS
ZIRCONIUM ALLOYS