Measurement of the Impurity Diffusion of Al in Ni by Laser Induced Breakdown Spectrometry (LIBS)

摘要

Laser Induced Breakdown Spectrometry (LIBS) has been used to determine the impurity diffusion coefficients of Al in Ni over the temperature range of 1273 to 1623 K. The diffusion coefficients ranged from 3.78X10~(-15) to 1.92X10~(-12) m~2s~(-1). These data are in good agreement with previously published result obtained by SIMS measurements. It was also found that the diffusivities of Al between 1573 and 1623 K (i.e., just below the melting temperature, T_m=1728 K) are higher than those expected, assuming a linear temperature dependence on an Arrhenius plot. These positive deviations from an Arrhenius line indicate the possibility of a divacancy diffusion mechanism. To clarify this phenomenon, more careful experiments will be needed. The activation energy and pre-exponential factor over the entire temperature range are Q=290 kJmol~(-1) and D_o=2.9 X10~(-3) m~2s~(-1) respectively.