The Inhibitory Action of the Extracts of Adathoda vasica, Eclipta alba, and Centella asiatica on the Corrosion of Mild Steel in Hydrochloric Acid Medium: A Comparative Study

Table 3

Potentiodynamic polarization parameters for mild steel in 1N HCl containing various concentrations of the plant extracts.

Name of the plant extract	Conc. of extract (% in v/v)	𝐸corr (V)	𝐼corr (mA/cm^2)	Tafel slope mV/decade		Inhibition efficiency (%)
				𝑏𝑎	𝑏𝑐
Blank	—	−0.510	3.57	78	122	—
Adathoda vasica	2.0	−0.512	0.21	78	124	94.1
	4.0	−0.491	0.14	76	122	96.1
	6.0	−0.493	0.02	74	120	99.2
	8.0	−0.493	0.02	74	120	99.2
	10.0	−0.508	0.06	76	122	97.2
Eclipta alba	2.0	−0.494	0.32	80	126	91.0
	4.0	−0.502	0.20	78	124	94.4
	6.0	−0.494	0.10	76	126	97.2
	8.0	−0.496	0.01	74	122	99.7
	10.0	−0.482	0.06	78	124	98.3
Centella asiatica	2.0	−0.492	1.47	76	128	58.8
	4.0	−0.491	1.22	78	126	65.8
	6.0	−0.493	0.97	80	122	72.8
	8.0	−0.470	0.74	74	126	79.3
	10.0	−0.492	0.51	76	124	85.7