Table 3.

Polarization parameters for the copper corrosion in 1.0 M H₂SO₄ solution and in the presence of the examined surfactants at 298 K.

Surf	Conc. (mg/l)	− Ecorr (mV(SCE))	βa (mV/dec.)	− βc (mV/dec.)	icorr (µA/cm2)	SD	Rp (ohm cm2)	% IE	θ
	0	44	42	95	288	26.221	44	–	–
AS	100	37	40	93	167	7.841	73	42	0.420
	200	40	39	94	107	6.014	112	63	0.628
	300	36	40	89	86	4.742	140	70	0.701
	400	34	37	87	72	4.602	157	75	0.750
	500	37	41	85	60	2.897	200	79	0.792
HS	100	42	42	83	156	7.021	78	46	0.458
	200	41	37	85	98	6.214	114	66	0.659
	300	38	39	84	84	5.127	138	71	0.708
	400	36	42	90	72	3.978	173	75	0.750
	500	41	49	92	66	2.719	211	77	0.771
TS	100	42	39	98	115	6.081	106	60	0.600
	200	39	37	88	78	4.001	145	73	0.729
	300	42	39	92	58	3.578	205	80	0.799
	400	37	41	87	46	2.397	263	84	0.840
	500	33	44	84	40	2.415	314	86	0.861

AS sodium N-dodecyl asparagine, HS sodium N-dodecyl histidine, TS sodium N-dodecyl tryptophan.