Long-time Stability of Electrochemical Ni-layers on Aluminium Applied with Different Pretreatments

摘要

Several differently plated types of nickel layers on aluminium substrates were studied with respect to their corrosion and diffusion barrier properties. For the deposition, different acid one-step pretreatment methods were examined. It was found, that tensile strengths of more than 50 N/mm{sup}2 can be achieved. In addition, the long-time stability at elevated temperatures was determined. After heat treatment at different temperatures in the range of 350°C to 400°C, the formation of NiAl alloys was detected by X-ray diffraction. The growth constants of the NiAl alloy was calculated for different temperatures from SEM and EDX measurements