Electrochimica Acta, Vol.69, 371-378, 2012
Electrochemical corrosion behavior of gas atomized Al-Ni alloy powders
This is a study describing the effects of microstructure features of spray-formed Al-Ni alloy powders on the electrochemical corrosion resistance. Two different spray-formed powders were produced using nitrogen (N-2) gas flow (4 and 8 bar were used). Electrochemical impedance spectroscopy (EIS), potentiodynamic anodic polarization techniques and an equivalent circuit analysis were used to evaluate the electrochemical behavior in a dilute 0.05 M NaCl solution at room temperature. It was found that a N-2 gas pressure of 8 bar resulted in a microstructure characterized by a high fraction of small powders and fine cell spacings, having improved pitting potential but higher corrosion current density when compared with the corresponding results of a coarser microstructure array obtained under a lower pressure. A favorable effect in terms of current density and oxide protective film formation was shown to be associated with the coarser microstructure, however, its pitting potential was found to be lower than that of the finer microstructure. (C) 2012 Elsevier Ltd. All rights reserved.