Atom vacancies and their effects on the properties of NbN containing carbon, oxygen, or boron. I. Phase boundary, thermodynamics, and lattice parameter
The NbC-NbN and NbN-NbO systems were studied by density and lattice parameter measurements to determine the concentration of atom vacancies in the metal and nonmetal sublattices of the cubic (Bl) structure as a function of pressure, temperature, and composition. Equations are given which define the thermodynamic behavior. Metal vacancies which occur near the nitrogen rich end of the NbN-NbC system and throughout the NbN-NbO system have a marked effect on the lattice parameter. The behavior of the lattice parameter can be explained if the niobium atoms increase in size in proportion to the number of electrons transferred from the nonmetal sublattice. The phase boundary of the cubic phase at 1643$sup 0$K and 1.0 is Nb$sub 0$$.$$sub 9$$sub 9$$N$$sub 0$$.$$sub 92$. Dissolved oxygen and to a less extent carbon cause the atom ratio at this boundary to increase. Equations are given which allow the boundary to be calculated at other temperatures and pressures. 13 figures. (auth)
- Research Organization:
- Los Alamos Scientific Lab., NM
- NSA Number:
- NSA-33-009742
- OSTI ID:
- 4128041
- Journal Information:
- High Temp. Sci., v. 7, no. 2, pp. 103-121, Journal Name: High Temp. Sci., v. 7, no. 2, pp. 103-121; ISSN HITSA
- Country of Publication:
- United States
- Language:
- English
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CARBONITRIDES
CHEMICAL COMPOSITION
DENSITY
EQUATIONS
LATTICE PARAMETERS
N50130* --Metals
Ceramics
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PRESSURE DEPENDENCE
QUANTITY RATIO
TEMPERATURE DEPENDENCE
VACANCIES