Table 7. Potentiodynamic Polarization Data for Carbon Steel in 1.0 M HCl with and without KI and Inhibitors + KI at 25 °C.

inhibitors	conc. (M)	–Ecorr (Mv)	icorr (μA cm2)	βc (mV dec–1)	βa (mV dec–1)	corrosion rate (CR) (mp y–1)	θ	%IE
CMBTAP	blank (1.0 M HCl)	420	118.5	125.77	86.8	55.36
	0.01 M KI	443.7	66.4	101.85	93.66	30.59	0.428	22.8
	1 × 10–5 + 0.01 M KI	448	23.2	95.04	107.7	10.93	0.804	80.4
	5 × 10–5 + 0.01 M KI	464	19.09	64.32	107.5	8.5	0.838	83.8
	10 × 10–5 + 0.01 M KI	446	17.42	64.2	104.2	7.75	0.853	85.3
	15 × 10–5 + 0.01 M KI	472	14.23	58.5	96.4	5.25	0.879	87.9
	20 × 10–5 + 0.01 M KI	476	8.1	63.6	100.8	3.75	0.932	93.2
CBAN	1 × 10–5 + 0.01 M KI	446	36.5	102.5	96.2	18.9	0.692	69.2
	5 × 10–5 + 0.01 M KI	453	28.1	81.1	94.3	14.1	0.763	76.3
	10 × 10–5 + 0.01 M KI	462	25.9	80.5	110.6	12.1	0.782	78.2
	15 × 10–5 + 0.01 M KI	465	23.5	70.0	106.3	11.2	0.80	80
	20 × 10–5 + 0.01 M KI	451	18.8	60.3	74.7	8.74	0.842	84.2
CBAMP	1 × 10–5 + 0.01 M KI	445	24.4	77.9	96.9	11.3	0.795	79.5
	5 × 10–5 + 0.01 M KI	453	21.6	71.5	107.8	10.1	0.82	82
	10 × 10–5 + 0.01 M KI	461	19.7	83.0	102.4	8.95	0.834	83.4
	15 × 10–5 + 0.01 M KI	466	14.3	65.1	88.6	6.8	0.879	87.9
	20 × 10–5 + 0.01 M KI	470	11.5	50.5	76.0	5.3	0.905	90.5