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

Table 3

Electrochemical impedance parameters for mild steel in 1 M HCl in absence and presence of different concentrations of Kalmegh (Andrographis paniculata) extract.

Acid Solution	Inhibitor (ppm)	𝑅𝑠 (Ωcm^2)	𝑅ct (Ωcm^2)	𝑌0 (Ω^−1s^𝑛cm^−2)	n	𝐶dl (𝜇Fcm^−2)	𝐸 (%)
1 M HCl	0	1.203	9	250	0.827	67.2	—
	180	1.253	21	158	0.864	65.8	58.5
	240	1.088	27	146	0.867	61.9	68.5
	300	1.137	99	105	0.885	56.9	91.4
	600	1.086	108	106	0.866	52.4	92.1
	1200	1.337	491	75	0.846	40.4	98.2