Diffusion in the Joining Process of Magnesia to Nickel Metal

The interdiffusion coefficients in the system NiO–MgO at 1473 to 1673 K were determined from the concentration distributions of Ni/NiO/MgO joining parts. The average values of interdiffusion coefficients at each composition were represented by\ ildeD=4.25×10−9exp{−186000(J)⁄RT}m2s−1.The increase of interdiffusion coefficients with the increase of NiO-concentrations was represented in terms of the exponential dependence. The interdiffusivities in NiO-rich region were roughly equal to the results obtained by Blank et al. and Appel et al. on single crystal couples. At low NiO-concentrations, however, the values of this work were larger than their values.