Modelling of the Growth of Carbide Layers in Tantalum

The kinetics of tantalum carburization is studied between 1623 and 1773 K. Within this temperature range, the diffusion coefficients D sub TaC exp C =3.3.10 exp -9 exp(-200000/RT) and D sub Ta(2)C exp C = 3.5.10 exp -7 exp(-261000/RT) for carbon in the TaC and Ta sub 2 C phases are calculated from parabolic constants of the growth of TaC and Ta sub 2 C carbide layers and values and composition at the phases boundaries.