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

Table 4

Potentiodynamic polarization parameters for mild steel without and with different concentrations of Kalmegh (Andrographis paniculata) extract in 1 M HCl.

Name of inhibitor	Conc. Of inhibitor (ppm)	Tafel data					Linear polarization data
		𝐸corr	𝐼corr	𝛽𝑎	𝛽𝑐	𝐸	𝑅𝑝	𝐸
		(mV versus SCE)	(𝜇Acm^−2)	(mV/dec)	(mV/dec)	(%)	(Ωcm^2)	(%)
1 M HCl	0	−446	1540	90	121	—	9.7	—
	180	−460	408	63	114	73.5	24.3	60.1
	240	−461	399	59	103	74	29.7	67.3
	300	−489	82	82	156	94.6	152	93.6
	600	−462	59	58	104	96.1	160.4	93.9
	1200	−486	37	38	36	98	383.5	97.4