Naturally Occurring Elettaria cardamomum Extract as a Corrosion Inhibitor for the Dissolution of Zinc in 1.0 M HCl

Table 2

Electrochemical parameters for zinc in absence and presence of different concentrations of inhibitor in 1.0 M HCl solution at 30°C obtained from Tafel polarization curves.

Inhibitor concentration (ppm)	−𝐸corr (mV SCE)	𝑏𝑎 (mV dec^−1)	𝑏𝑐 (mV dec^−1)	𝐼corr (mA cm^−2)	θ	IE (%)
HCl (1 M)	996	0.43	0.49	2.41	—	—
100	992	0.58	0.59	0.91	0.62	62.30
200	985	0.66	0.64	0.62	0.74	74.30
300	981	0.76	0.72	0.43	0.82	82.20
400	980	0.86	0.76	0.22	0.90	90.90
500	977	0.88	0.81	0.15	0.93	93.80