Diffusion coefficients of nitrogen in liguid iron were measured with a capillary reservoir method in a temperature range from 1 550° to 1680°C.
In order to obtain accurate date, the experiments were made under various conditions. The notices on the experiments were given as follows;
1) To obtain an ideal concentration profile obeyed to Fick's second law, a crucible must be set on a place where is a temperature difference between a top and a bottom of the crucible with 10°C.
2) The longer the length of diffused media is, the more accurate data can be obtained.
3) The smaller diameter of the crucible is, the lower values are generally obtained, but when the diameter is less than 6mm, the effects of diameter on the diffusion coefficient are negligible.
The results are summorized as follows.
4) The diffusion coefficient of nitrogen in the liquid iron at 1600°C is obtained as, D=(0.92±0.10)×10-4cm2/sec.
The relation between diffusion coefficient and temperature is given as following equation.
log D=-3800/T-3.01
5) The activiation energy of Arrhenius equation is obtained as, E=17.5 kcal/mol.
