Inhibition Behaviour of Some Isonicotinic Acid Hydrazides on the Corrosion of Mild Steel in Hydrochloric Acid Solution

Table 4

Polarization parameters and corresponding inhibition efficiency (IE) for the corrosion of the MS in 0.5 M HCl without and with addition of various concentrations of INIMH and INPMH at 30°C.

Inhibitor	Concentration; (ppm)	−𝐸corr (mv)	𝑖corr (μA cm^−2)	IE (%)
Blank	0	508	2617.0	—
INIMH	200	468	687.0	73.74
	300	466	509.2	80.54
	400	458	498.8	80.94
	500	437	434.3	83.40
INPMH	200	485	871.5	66.69
	300	477	835.5	68.07
	400	465	526.8	79.87
	500	456	470.0	82.04