ANOMALOUS DIFFUSION OF 14C IN TIC0.67

The self-diffusion of 14C in TiC0.67 was studied in the temperature range 1745°-2720°C. The diffusivity, which exhibits a discontinuity at 2080°C, can be represented by two expressions: D *0.67=(2.85±0.20)×10 -4exp[-(49 600±300)/RT] cm2/sec above 2080°C and D*0.67=(1.14±0.66)×10 2exp[-(109,900±2000)/RT] cm2/sec below this temperature. No discontinuity was found in carbon saturated TiC0.97 and the self-diffusion coefficient for this composition can be described to a temperature of 2720°C by the single expression D* 0.97=(6.98±1.24) exp[-(95 300±700) / RT] cm 2/sec. © 1968 The American Institute of Physics.