Determination of diffusion coefficients of Zn, Co and Ni in aluminium by a resistometric method

Abstract The impurity diffusion parameters of Zn, Co and Ni have been determined in aluminium by measurements of electrical resistance. It is shown experimentally that in the case of Co and Ni, surface layers with constant concentrations were formed during the isothermal diffusion treatments and so the resistance measurements made possible the determination of the temperature dependence of the saturation concentrations too. It is also shown that the determination of the diffusion activation energy is possible from resistance measurements when the initial and boundary conditions are not exactly known (but when they do not vary with temperature). The measurements gave for the pre-exponential factors (D 0) and the energies of activation (Q) : D 0 Zn = (0.20 ± 0.08) cm2/s, QZn = (1.25 ± 0.02) eV; D 0co = (141 ± 137)cm2/s, Q Co = (1.75 ± 0.07) eV; D 0 Ni = (4.4 ± 3.l) cm2/s, Q N1 = (1.51 ± 0.06) eV, respectively. The diffusion parameters of Zn and Co are in good agreement with previous results in the literatur...