Accession Number : AD0483205

Title :   CRYSTAL STRUCTURE ANALYSIS OF DIMOLYBDENUM CARBIDE.

Descriptive Note : Technical rept. Nov 64-Nov 65,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH

Personal Author(s) : Fenter, John R. ; Vahldiek, Fred W. ; Lynch, Charles T.

Report Date : JAN 1966

Pagination or Media Count : 38

Abstract : X-ray diffraction crystal structure analysis was performed on single crystal dimolybdenum carbide. Single crystal fragments cleaved from boules were aligned by rotational and Laue symmetry techniques. Three-dimensional reciprocal lattice data were obtained by the precession method. M02C was found to be hexagonal with lattice constants, a=3.010 plus or minus 0.004 A and c=4.727 plus or minus 0.006 A, determined by the method of least squares on an IBM 7094 computer. Observed structure factors were computed for all the reflections and calculated structure factors were computed for all the reflections, and calculated structure factors were computed assuming the space group D4/6H - P 6(3)/mmc. Comparison of observed and calculated structure factors for the zero level of the secondary axis (a-axis) resulted in a residual of 0.029 and a temperature coefficient of 0.606 cm(-16). The unit cell volume of 37.102 A3 was calculated. Quantitative analysis indicated the composition Mo2C 0.959 with 31.96 At% carbon, corresponding to alpha-M02C.

Descriptors :   *CARBIDES), (*MOLYBDENUM COMPOUNDS, (*SINGLE CRYSTALS, CRYSTAL STRUCTURE), PHASE STUDIES, DENSITY, X RAY DIFFRACTION, CRYSTAL DEFECTS, MICROSTRUCTURE, EMISSIVITY, HARDNESS, ROTATION, THERMODYNAMICS, MELTING POINT, ELECTRIC ARCS, POWDERS, SYMMETRY(CRYSTALLOGRAPHY), COMPUTERS, TABLES(DATA), QUENCHING, CARBON, ABSORPTION, GRAPHICS, PRECESSION, TEST METHODS, REFLECTION.

Subject Categories : Properties of Metals and Alloys
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE