Effects of NaH 2 PO 2 concentration and deposition potential on microstructural characteristics and corrosion properties of electrodeposited amorphous Fe–P coatings

This study reports the influence of NaH2PO2 concentration and deposition potential on the microstructural characteristics and corrosion properties of fully amorphous electrodeposited Fe–P coatings. The morphology and P content of the coatings were observed and the effect of the processing parameters on the surface roughness, deposition rate, and current efficiency were investigated. The morphology and P content of the coating varied significantly with the NaH2PO2 concentration, but the deposition potential did not significantly influence these properties. As the P content and morphology determine electrochemical corrosion properties, the deposited Fe–P film with the best anti-corrosion properties was determined by analysing the corrosion properties of the coatings in 3.5 wt.% NaCl solution through potentiodynamic polarisation and electrochemical impedance spectroscopy; the corrosion morphology and corrosion products were also characterised. This study can provide new insights into the corrosion behaviour of amorphous Fe–P coatings and provide guidelines for industrial production.