Influence of annealing temperature on corrosion inhibition of Cu coated with Ni in NaCl solution

School of Physics, College of Science, University of Tehran - North-Kargar Street, Tehran, Iran

^(a) savaloni@khayam.ut.ac.ir (corresponding author)

Received: 1 July 2019
Accepted: 27 November 2019

Abstract

Copper substrates were coated with a 100 nm nickel thin film and post-annealed with a 300 sccm flow of nitrogen at different temperatures. The formation of nickel nitride is confirmed by x-ray diffraction analyses. Atomic force microscopy (AFM) results showed morphological changes by variation of the annealing temperature which is explained on the basis of physical processes (e.g., diffusion, penetration depth). The electrochemical behavior of the samples in 0.6 M NaCl solution was investigated by means of electrochemical impedance spectroscopy and polarization measurements. EIS data were confirmed by Kramers-Kronig transformations and by the fitting of these data with equivalent electrical circuits. Results showed that the 473 K sample has the highest corrosion inhibition efficiency (). This can be due to the large grain size, hence a lower number of grain boundaries and the lowest surface roughness and porosity of this sample.