Addition of oxygen to and distribution of oxides in tantalum alloy T-111 at low concentrations

Technical Report · Wed Oct 01 04:00:00 EDT 1975

OSTI ID:7345549

Stecura, S

Oxygen was added at 820 and 990 C at an oxygen pressure of about .0003 torr. The technique permitted predetermined and reproducible oxygen doping of the tantalum alloy (T-111). Based on the temperature dependency of the doping reaction, it was concluded that the initial rates of oxygen pickup are probably controlled by solution of oxygen into the T-111 lattice. Although hafnium oxides are more stable than those of tantalum or tungsten, analyses of extracted residues indicate that the tantalum and tungsten oxides predominate in the as-doped specimens, presumably because of the higher concentrations of tantalum and tungsten in the alloy. However, high-temperature annealing promotes gettering of dissolved oxygen and oxygen from other oxides to form hafnium oxides. Small amounts of tantalum and tungsten oxides were still present after high temperature annealing. Tungsten oxide (WO3) volatilizes slightly from the surface of T-111 at 990 C but not at 820 C. The vaporization of WO3 has no apparent effect on the doping reaction. (Author) (GRA)

• OSTI ID: 7345549
• Report Number(s): N-75-33223; NASA-TM-X-3300; E-8358
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ANNEALING
CHALCOGENIDES
DOPED MATERIALS
HAFNIUM COMPOUNDS
HAFNIUM OXIDES
HEAT TREATMENTS
OXIDES
OXYGEN ADDITIONS
OXYGEN COMPOUNDS
PHASE STUDIES
TANTALUM ALLOY-T111
TANTALUM ALLOYS
TANTALUM BASE ALLOYS
TANTALUM COMPOUNDS
TANTALUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
TUNGSTEN OXIDES