SELF-DIFFUSION OF C-14 IN POLYCRYSTALLINE BETA-SIC

The14C self-diffusion coefficients for both lattice (D lc * ) and grain boundary (D bc * ) transport in high purity CVD β-SiC are reported for the range 2128 to 2374 K. The Suzuoka analysis technique revealed that D bc * is 105 to 106 faster than D bc * ; the respective equations are given by {Mathematical expression} A vacancy mechanism is assumed to be operative for lattice transport. From the standpoint of crystallography and energetics, reasons are given in support of a path of transport which involves an initial jump to a vacant tetrahedral site succeeded by a jump to a normally occupied C vacancy. © 1979 Chapman and Hall Ltd.