Some Thiophene Derivatives as Corrosion Inhibitors for Carbon Steel in Hydrochloric Acid

Table 8

Electrochemical kinetic parameters obtained from EFM technique for carbon steel in 1 M HCl in the absence and presence of different concentrations of compounds.

Compound	Concentration × 10^−5 (M)	𝑖corr (𝜇A cm^−2)	𝛽𝑐 (mV dec^−1)	𝛽𝑎 (mV dec^−1)	𝑘corr. (mpy)	CF-2	CF-3	𝜃	%IE
Blank	0	913.3	149	132	420.8	1.90	3.34	—	—
A	2	535.4	103	97	246.7	1.86	2.88	0.414	41.4
	4	522.7	106	98	240.8	1.85	2.20	0.428	42.8
	6	408.0	59	50	188.0	2.01	2.19	0.553	55.3
	8	338.7	97	92	156.0	1.37	2.37	0.629	62.9
	10	222.7	100	97	102.6	1.88	2.60	0.756	75.6
	12	138.9	110	97	64.0	1.88	2.42	0.848	84.8
B	2	529.9	92	106	242.1	1.88	3.08	0.420	42.0
	4	375.1	103	92	171.4	2.25	1.73	0.589	58.9
	6	322.8	43	37	147.5	1.95	2.29	0.647	64.7
	8	314.9	101	93	143.9	2.10	2.88	0.655	65.5
	10	302.0	39	35	138.0	1.94	2.87	0.669	66.9
	12	204.9	102	93	93.6	1.98	2.45	0.776	77.6
C	2	503.1	101	90	229.9	1.86	2.88	0.449	44.9
	4	433.5	102	94	198.1	1.85	2.20	0.525	52.5
	6	341.1	98	88	155.9	2.01	2.19	0.627	62.7
	8	337.1	101	95	154.0	1.37	2.37	0.631	63.1
	10	307.5	54.0	78	140.5	1.88	2.60	0.663	66.3
	12	288.8	102.6	93	131.9	1.88	2.42	0.684	68.4