Cohesion properties of carbon-tungsten interfaces

First principles calculation reveals that the density functional dispersion correction (DFT-D2) method, instead of generalized gradient approximation (GGA) and local density approximation (LDA), should be appropriate to reflect various properties of W-C interfaces, and that the C/W interface (deposition of C on W) possesses higher interface strength and lower interface energy than the W/C interface (deposition of W on C). Calculations also show that compared with the W/C interface, a stronger chemical bonding is formed in the C/W interface with lower W-C bond length as well as bigger charge transfers between C and W atoms. In addition, it is also found that the WC carbide should be more easily formed in the C/W interface than that in the W/C interface. The calculated results are in good agreement with experimental observations in the literature. (C) 2014 Elsevier Ltd. All rights reserved.