OXIDATION OF NIOBIUM

Journal Article · Sat Apr 01 04:00:00 EST 1961 · J. Inst. Metals

OSTI ID:4065394

Hurlen, T

The reaction of niobium with oxygen at pressures from 10/sup -//sup 2/ to 760 mm Hg and temperatures from 150 to 1000 deg C was studied by gravimetric and volumetric rate measurements and by x-ray diffraction. electron diffraction, electron microscopy, and metallographic techniques. The time-dependence indicates the following consecutive oxidation stages: linear(I), parabolic(II), a rate-increasing transition, linear(III), parabolic(IV), and parabolic(V). The effect of oxygen pressure and of tempcrature on the occurrence and rate of the various types of oxidation is quantitatively discussed. A close correlation was found between the oxidation rate and the oxidation products formed. The solution of oxygen in the niobium lattice plays an essential role. This reaction, free from interference by simultaneous formation of oxide on the metal surface, was studied. Among the oxidation products, three phases with structures closely related to that of pure niobium were detected, only one of which has previously been described. In the case of specimens oxidized above 800 deg C, pentoxide whiskers appear on top of the oxide scale. Whiskers up to 30 mu long were observed. (auth)

• Research Organization: Sentralinstitutt for Industriell Forskning, Oslo
• NSA Number: NSA-15-019786
• OSTI ID: 4065394
• Journal Information: J. Inst. Metals, Journal Name: J. Inst. Metals Vol. Vol: 89
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CHEMICAL REACTIONS
CONFIGURATION
DIFFRACTION
ELECTRON MICROSCOPY
ELECTRONS
LATTICES
METALLOGRAPHY
METALS, CERAMICS, AND OTHER MATERIALS
NIOBIUM
NIOBIUM OXIDES
OXIDATION
OXYGEN
PRESSURE
QUALITATIVE ANALYSIS
TEMPERATURE
X RADIATION