Influence of the complexing agent sodium citrate on the chemical composition, surface morphology and corrosion resistance of Ni–Fe electrodeposits.

Autor: da Silva, G. P., de Lima, R. N., Santos, F. J. N., de Menezes, F. P. S., Morais, L. P. L., da Silva Filho, L. F.
Předmět:
Zdroj: Transactions of the Institute of Metal Finishing; Sep2019, Vol. 97 Issue 5, p230-236, 7p
Abstrakt: A comparative study has been made of the influence of the complexing agent, sodium citrate, on the characteristics of Ni–Fe alloys obtained by electrodeposition. The alloys were synthesised from modified Watts electrolytes with different proportions of Ni2+ and Fe3+ ions. Energy-dispersive X-ray spectroscopy (EDS) analyses showed that the coatings obtained from electrolytes without sodium citrate (CWOCs) had higher Fe values than Ni and those obtained with electrolytes containing complexing agent (CWCs) presented an inverse behaviour. Micrographs obtained by scanning electron microscopy (SEM) showed the formation of uniform, homogeneous and nodular deposits, typical of Ni coatings. However, the presence of microcracks and porosity in the CWCs was verified. Potentiodynamic linear polarisation (PLP) and electrochemical impedance spectroscopy (EIS) analysis identified corrosion processes with active dissolution in 0.1 mol L−1 NaCl medium in all the analysed deposits, with the CWOCs being more resistant than the CWCs. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index