An Electrochemical Synthesis of Reduced Graphene Oxide/Zinc Nanocomposite Coating through Pulse-Potential Electrodeposition Technique and the Consequent Corrosion Resistance

Table 2

Electrochemical parameters of bare steel, rGO coating, galvanized steel, and rGO-Zn coating; potentiodynamic polarization tests of coatings were accomplished after immersion in 3.5 wt.% NaCl solution for 1 h with scan rate 1 mV/s while EIS tests were achieved at immersing in 0.1 M KCl solution at frequency range of 10⁻³ to 10⁵ Hz with 5 mV ac amplitude and OCP condition (stability time: 30 min).

Surface	Polarization test				EIS test
	(μA/cm^2)	(V/SCE)	(mV/decade)	(mV/decade)	(Ω⋅cm^2)	(μF/cm^2)		(Ω⋅cm^2)	(μF/cm^2)	(Ω⋅cm^2)	(Ω⋅cm^2)	CR (mm/year)
Bare steel	1.5	−0.58	34.9	50.6	85.2	79.3	1	-	-	337.6	337.6	0.035
rGO coating	1.6	−0.45	74.5	39.5	85.11	3137	0.82	679.1	431.1	16.02	695.1	0.037
Galvanized steel	3.0	−1.08	21.5	39.7	85.03	30.2	0.68	602.5	570.5	697	1299.5	0.07
rGO-Zn coating	0.007	−0.77	47.0	47.2	90.73	225.4	0.75	3359	23.7	37.63	3396.6