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

Abstract

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.]

Authors:
 [1]
  1. (Sandia National Laboratories, Livermore, California 94550 (United States))
Publication Date:
OSTI Identifier:
6385152
Alternate Identifier(s):
OSTI ID: 6385152
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology, A
Additional Journal Information:
Journal Volume: 17:5; Journal ID: ISSN 0734-2101
Country of Publication:
United States
Language:
English
Subject:
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, & Refractories-- Mechanical Properties; 360603 -- Materials-- Properties

Citation Formats

McCarty, K.F. Preferred orientation in carbon and boron nitride: Does a thermodynamic theory of elastic strain energy get it right. [C; BN]. United States: N. p., 1999. Web. doi:10.1116/1.581940.
McCarty, K.F. Preferred orientation in carbon and boron nitride: Does a thermodynamic theory of elastic strain energy get it right. [C; BN]. United States. doi:10.1116/1.581940.
McCarty, K.F. Wed . "Preferred orientation in carbon and boron nitride: Does a thermodynamic theory of elastic strain energy get it right. [C; BN]". United States. doi:10.1116/1.581940.
@article{osti_6385152,
title = {Preferred orientation in carbon and boron nitride: Does a thermodynamic theory of elastic strain energy get it right. [C; BN]},
author = {McCarty, K.F.},
abstractNote = {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.]},
doi = {10.1116/1.581940},
journal = {Journal of Vacuum Science and Technology, A},
issn = {0734-2101},
number = ,
volume = 17:5,
place = {United States},
year = {1999},
month = {9}
}