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Lower‐Temperature Modifications of Nb 2 C and V 2 C
Author(s) -
RUDY ERWIN,
BRUKL CHARLES E.
Publication year - 1967
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1967.tb15101.x
Subject(s) - isostructural , orthorhombic crystal system , hexagonal crystal system , crystallography , carbide , atmospheric temperature range , materials science , chemistry , crystal structure , metallurgy , thermodynamics , physics
The orthorhombic, low‐temperature α‐modification of Nb 2 C has a structure similar to that of ζ‐Fe 2 N (a = 12.36 A, b = 10.89 5 A, c = 4.96 8 A) and transforms at ∼1200°C into the hexagonal ε‐Fe 2 N type. A second transition at approximately 2500°C is associated with the destruction of long range order in the carbon sublattice. Alpha‐divanadium carbide (orthorhombic, a = 11.49 A, b = 10.06 A, c = 4.55 A) is isostructural with α‐Nb 2 C and transforms at ∼800°C into the hexagonal high‐temperature modification. The structures of α‐V 2 C and α‐Nb 2 C are distorted modifications related to the ε‐Fe 2 N type.