Measurement of the impurity diffusivity of Cu in Fe by Laser Induced Breakdown Spectrometry

The impurity diffusion coefficients of Cu in Fe have been determined in the temperature range of 1073 - 1163 K by means of Laser Induced Breakdown Spectrometry (LIBS). The volume diffusion coefficients for Cu impurity diffusion in alpha-iron found in this work are in good agreement with the previously published result. The grain boundary diffusion coefficient s delta D(gh) was also calculated using the volume diffusivity and processing the tails of the measured profiles. The values of the activation energy for volume and grain boundary diffusion were approximately 280 and 161 kJmol(-1), respectively. This indicates the possibility of a monovacancy diffusion mechanism in case of volume diffusion. The results for the diffusion coefficients are D(v)= 2.2 x 10(-2) exp(-280 kJmol(-1)/RT) m(2)s(-1) and s delta G(gb) = 2.6 x 10(-11) exp(- 161 kJmol(-1)/RT) m(3)s(-1).