Aqueous Extract of Kalmegh (Andrographis paniculata) Leaves as Green Inhibitor for Mild Steel in Hydrochloric Acid Solution

Table 1

Corrosion parameters for mild steel in aqueous solution of 1 M HCl in presence and absence of different concentrations of Kalmegh (Andrographis paniculata) extract from weight loss measurements at 308 K for 3 h.

Inhibitor concentration (ppm)	Weight loss (mgcm^−2)	𝐸 (%)	𝐶𝑅 (mm/y)
1 M HCl	20.9	—	77.9
60	16.3	22.4	60.5
90	7.7	63.3	28.6
120	7.3	65.2	27.1
180	2.8	86.7	10.4
240	2.6	87.6	9.6
300	1.6	92.4	5.9
600	0.7	96.7	2.6
1200	0.4	98.1	1.5