Preferred orientation in carbon and boron nitride: Does a thermodynamic theory of elastic strain energy get it right. [C; BN]

Journal Article · Wed Sep 01 00:00:00 EDT 1999 · Journal of Vacuum Science and Technology, A

DOI:https://doi.org/10.1116/1.581940· OSTI ID:6385152

McCarty, K F ^[1]

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1. Sandia National Laboratories, Livermore, California 94550 (United States)

We address whether the elastic strain-energy theory (minimizing the Gibbs energy of a stressed crystal) of McKenzie and co-workers [D. R. McKenzie and M. M. M. Bilek, J. Vac. Sci. Technol. A [bold 16], 2733 (1998)] adequately explains the preferred orientation observed in carbon and BN films. In the formalism, the Gibbs energy of the cubic materials diamond and cubic boron includes the strain that occurs when the phases form, through specific structural transformations, from graphitic precursors. This treatment violates the requirement of thermodynamics that the Gibbs energy be a path-independent, state function. If the cubic phases are treated using the same (path-independent) formalism applied to the graphitic materials, the crystallographic orientation of lowest Gibbs energy is not that observed experimentally. For graphitic (hexagonal) carbon and BN, an elastic strain approach seems inappropriate because the compressive stresses in energetically deposited films are orders of magnitude higher than the elastic limit of the materials. Furthermore, using the known elastic constants of either ordered or disordered graphitic materials, the theory does not predict the orientation observed by experiment. [copyright] [ital 1999 American Vacuum Society.]

• OSTI ID: 6385152
• Journal Information: Journal of Vacuum Science and Technology, A, Vol. 17:5; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON COMPOUNDS
BORON NITRIDES
CARBON
ELASTICITY
FILMS
FREE ENERGY
PHASE TRANSFORMATIONS
STRAINS
TEXTURE
THERMODYNAMICS
THIN FILMS
ELEMENTS
ENERGY
MECHANICAL PROPERTIES
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
PHYSICAL PROPERTIES
PNICTIDES
TENSILE PROPERTIES
THERMODYNAMIC PROPERTIES
360203* - Ceramics
Cermets
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