Anomalous Diffusion of 14C in TiC0.67

Abstract

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: D0.67*=(2.85±0.20)×10−4exp[−(49 600±300)/RT] cm2/sec above 2080°C and D0.67*=(1.14±0.66)×102exp[−(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] cm2/sec.