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 1

Corrosion parameters obtained from weight loss measurements for mild steel in 1N HCl containing various concentrations of the plant extracts.

Name of the plant extract	Conc. of the extract (% in v/v)	Corrosion rate (mmpy)	Inhibition efficiency (%)	Surface coverage (θ)
Adathoda vasica	Blank	30.67	—	—
	2.0	1.78	94.2	0.9419
	4.0	1.17	96.2	0.9618
	6.0	0.30	99.0	0.9902
	8.0	0.35	98.8	0.9885
	10.0	0.58	98.1	0.9811
Eclipta alba	Blank	30.67	—	—
	2.0	2.90	90.5	0.9054
	4.0	1.98	93.5	0.9354
	6.0	0.98	96.8	0.9680
	8.0	0.12	99.6	0.9960
	10.0	0.12	99.6	0.9960
Centella asiatica	Blank	30.67	—	—
	2.0	12.82	58.2	0.5820
	4.0	10.79	64.8	0.6482
	6.0	8.55	72.1	0.7212
	8.0	6.56	78.6	0.7861
	10.0	4.50	85.3	0.8532