Figure 1: XRD pattern of a) as-prepared graphene and b) graphene coated Zn sample

Figure 2: Raman spectrum of Graphene sample

Figure 3: SEM and EDAX image of graphene

Figure 4: Current verses potential curves for Zn alloy and Zn/graphene sample in different electrolytes

Figure 5: SEM image for Zn alloy sample in three different electrolytes

Figure 6: SEM image Zn/graphene samples in three different electrolytes

Figure 7: Nyquist plot for Zn alloy and Zn/graphene samples in different electrolyte

Figure 8: Equivalent circuit model of the impedance diagram

Alloy        

Zn

    Al

         Cu

        Mg

Fe

 Pb

Cd

Sn

 ZA-8         

Bal. 

8.0-8.8

 0.8-1.3   

 0.015-0.03

0.075

0.006

0.006

0.003

Table 1: Chemical composition (mass %) of ZA-8 zinc alloy

Electrolyte

Sample

Corrosion Potential
(vs. SCR.E.) V-1

Corrosion Current
(Acm-2) × 104

3.5 wt % NaCl

Zn

-1.259

7.52

ZnG

-1.085

2.82

0.1M Na2SO4

Zn

-0.972

9.98

ZnG

-0.873

7.43

0.1M KCl

Zn

-1.313

2.96

ZnG

-1.076

1.84

Table 2: Corrosion potential (Vcorr) and corrosion current (icorr) determined from Tafel curves of 3.5 w% NaCl, 0.1M Na2SO4 and 0.1 M KCl electrolyte