Corrosion parameters of C-steel electrode in 1 M HCl solution containing altered doses of inhibitors (I & II) at 25 °C from the PP technique.

Comp.	Conc., M	−Ecorr mV vs. SCE	i corr mA cm−2	β c mV dec−1		β a mV dec−1	C.R. mmy−1	θ	%IE
1 M HCl	00	531 ± 0.2028	422 ± 0.2028	42 ± 0.2028	22 ± 0.1453		220.6	—	—
Inhibitor (I)	1 × 10−6	515 ± 0.2431	246 ± 0.1155	26 ± 0.1421	13 ± 0.2906		130.0	0.459	45.9
	5 × 10−6	534 ± 0.2055	234 ± 0.2603	48 ± 0.1535	39 ± 0.2624		96.2	0.634	63.4
	9 × 10−6	494 ± 0.1452	214 ± 0.1764	47 ± 0.1214	50 ± 0.2224		75.4	0.791	79.1
	13 × 10−6	502 ± 0.1742	174 ± 0.2028	82 ± 0.1121	47 ± 0.2006		62.4	0.814	81.4
	17 × 10−6	512 ± 0.2102	101 ± 0.1732	74 ± 0.1074	85 ± 0.2421		45.1	0.834	83.4
	21 × 10−6	464 ± 0.2209	58 ± 0.1453	127 ± 0.231	57 ± 0.2028		29.2	0.906	90.6
Inhibitor (II)	1 × 10−6	516 ± 0.2119	223 ± 0.1732	20 ± 0.2333	15 ± 0.2082		119.5	0.644	64.4
	5 × 10−6	496 ± 0.2010	180 ± 0.2028	46 ± 0.1202	19 ± 0.1732		80.9	0.702	70.2
	9 × 10−6	504 ± 0.1753	126 ± 0.2010	45 ± 0.1732	32 ± 0.2082		45.9	0.725	72.5
	13 × 10−6	510 ± 0.1613	101 ± 0.1764	75 ± 0.1453	41 ± 0.1764		41.2	0.782	78.2
	17 × 10−6	498 ± 0.1421	80 ± 0.1453	67 ± 0.2027	39 ± 0.1154		36.6	0.837	83.7
	21 × 10−6	472 ± 0.1253	45 ± 0.1732	112 ± 0.233	67 ± 0.1245		20.9	0.924	92.4