Effect of Temperature on the Corrosion Resistance of Ni5Al Coating Deposited by Electric Arc in 3.5% NaCl Solution

The electrochemical behavior of the Ni5Al coating deposited by an electric arc was evaluated. Its behavior was evaluated in a saline solution as a function of temperature (20 degrees C, 40 degrees C, and 60 degrees C). The variation as a function of time of the Ni5Al coating's values of open circuit potential, linear polarization resistance, and the evolution of its electrochemical impedance spectra were analyzed. With this deposition technique, the rapid formation of thick coatings is achieved, which reduces the presence of interconnected porosity. Even though the microstructural characteristics showed the presence of trapped oxides, the electrochemical measurements carried out showed excellent corrosion resistance of the coating. The coating quickly develops a passive layer that allows it to rapidly reach thermodynamic equilibrium with the corrosive medium.