OXIDATION AND CONTAMINATION REACTIONS OF NIOBIUM AND NIOBIUM ALLOYS

Technical Report · Sun Feb 01 00:00:00 UTC 1959

DOI:https://doi.org/10.2172/4268078· OSTI ID:4268078

Klopp, W. D.; Maykuth, D. J.; Sims, C. T.; Jaffee, R. I.

Niobium was found to react linearly with air (600 to 1200 deg c) and with oxygen (400 to 1400 deg c). At 1400 deg c, a very rapid reaction with oxygen was observed. Contamination hardening during oxidation was attributed to diffusion of oxygen into the metal from the predominantly Nb/sub 2/O/sub 5/ scale. Alloying effects could be correlated with relative ionic size and valence of the alloy addition and with properties of the alloy-element oxides. Additions with smaller ionic size or higher valence improved oxidation behavior up to 15 at.% alloying. These additions included chromium, molybdenum, tungsten, and vanadium. Size effects predominated over valence effects. At alloying levels greater than 15 at.% elements having solid stable oxides, such as titanium and zirconium, improved the oxidation behavior. Elements with volatile oxides, such as molybdenum, rhenium, and vanadium decreased the oxidation resistance when added in amounts greater than 15 at. %. The most effective binary additions for improving oxidation resistance were chromium, molybdenum, titanium, and vanadium. A molybdenum-chromium alloy oxidized about 20% slower than the best binary alloy. The degree of improvement for the best alloys over unalloyed niobium ranged from a hundredfold at 600 deg c to sixfold at 1200 deg . The most effective additions were concluded to be those which form solid stable oxides of their own or which are capable of forming complex oxides such as spinels. (auth)

• Research Organization: Battelle Memorial Inst., Columbus, Ohio
• DOE Contract Number: W-7405-ENG-92
• NSA Number: NSA-13-008909
• OSTI ID: 4268078
• Report Number(s): BMI-1317
• Country of Publication: United States
• Language: English

Related Subjects

ADDITIVES
AIR
ALUMINUM OXIDES
CHEMICAL REACTIONS
CHROMIUM
CHROMIUM ALLOYS
CONTAMINATION
DIFFUSION
EFFICIENCY
ELECTRONS
HIGH TEMPERATURE
IONS
MAGNESIUM OXIDES
METALLURGY AND CERAMICS
MINERALS
MOLYBDENUM
MOLYBDENUM ALLOYS
MOLYBDENUM OXIDES
NIOBIUM
NIOBIUM ALLOYS
NIOBIUM OXIDES
OXIDATION
OXIDES
OXYGEN
RHENIUM OXIDES
SPINELS
STABILITY
STANDARDS
TEMPERATURE
TEMPERING
TITANIUM
TITANIUM OXIDES
TUNGSTEN
VALENCE
VANADIUM
VANADIUM OXIDES
VOLATILITY
ZIRCONIUM OXIDES