Colocid Dye - A Potential Corrosion Inhibitor for the Corrosion of Mild Steel in Acid Media

Sivakumar, Vadivel; Velumani, Kaithamalai; Rameshkumar, Subramaniam

doi:10.1590/1980-5373-MR-2017-0167

Vadivel Sivakumar ^**e-mail: cvabavani@gmail.com

Department of Chemistry, Sri Vasavi College, Erode, TamilNadu, India

Kaithamalai Velumani

Department of Chemistry, Sri Vasavi College, Erode, TamilNadu, India

Subramaniam Rameshkumar

Department of Chemistry, Sri Vasavi College, Erode, TamilNadu, India

https://orcid.org/0000-0002-3044-6594

*e-mail: cvabavani@gmail.com

Thumbnail

Figure 1
Structure of Colocid acid dye

Thumbnail

Figure 2
The Nyquist plots for MS electrode obtained in 1.0 M HCl and 0.5 M H₂SO₄ solutions in the absence and presence of Colocid dye at various concentrations

Thumbnail

Figure 3
Equivalent circuit for the mild steel surface-corrosive media interface

Thumbnail

Figure 4
Potentiodynamic polarization plots recorded for MS electrode in 1.0 M HCl and 0.5 M H₂SO₄ solutions in the absence and presence of Colocid dye at various concentrations

Thumbnail

Figure 5
Plot of differential capacitance vs. applied electrode potential in 1.0 M HCl and 0.5 M H₂SO₄ solutions in the absence and presence of Colocid dye

Thumbnail

Figure 6
Langmuir adsorption isotherm for the adsorption of Colocid dye onto MS surface in 1.0 M HCl and 0.5 M H₂SO₄ solutions

Thumbnail

Figure 7
SEM Monographs of Iron specimen in 1.0 M HCl (7a) and 0.5 M H₂SO₄ (7b) solutions in the absence of inhibitor

Thumbnail

Figure 8
SEM Monographs of Iron specimen in 1.0 M HCl (8a) and 0.5 M H₂SO₄ (8b) in the presence of inhibitor caption

Thumbnail

Table 1
Corrosion inhibition Efficiency values calculated from the weight loss measurements

Thumbnail

Table 2
Electrochemical impedance parameters for MS in 1.0 M HCl and 0.5 M H₂SO₄ solutions in the presence and absence of inhibitor.

Thumbnail

Table 3
Electrochemical parameters for MS in 1.0 M HCl and 0.5 M H₂SO₄ solutions in the presence and absence of inhibitor from potentiodynamic polarization curves.

Thumbnail

Table 4
Excess charge on MS electrode in 1.0 M HCl and 0.5 M H₂SO₄ solutions in the presence and absence of inhibitor.

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

Medium	Inhibitor concentration (ppm)	Corrosion rate (mpy)	Inhibition efficiency (IE%)
1MHCl	Blank	169.0	-
	5	99.37	41.2
	10	89.40	47.1
	20	79.26	53.1
	50	65.40	61.3
	100	32.11	81.0
	200	26.87	84.1
	400	20.52	87.8
	600	18.08	89.3
0.5M H₂SO₄	Blank	522.7	-
	5	395.7	24.3
	10	226.8	56.6
	20	192.8	63.1
	50	167.7	67.9
	100	125.9	75.9
	200	91.47	82.5
	400	83.11	84.1
	600	68.47	86.9

Medium	Inhibitor concentration (ppm)	Rct Ωcm²	Y₀(x10^-6) Ω^-1cm^-2	n	Inhibitor Efficiency
1.0 MHCl	Blank	18.8	262	0.970	-
	5	32.2	253	0.938	41.6
	10	35.7	205	0.940	47.3
	20	40.1	176	0.967	52.9
	50	48.8	169	0.968	61.5
	100	100	143	0.966	81.2
	200	120	127	0.974	84.4
	400	142	112	0.978	86.8
	600	189	101	0.969	90.1
0.5M H₂SO₄	Blank	14.6	145	0.902	-
	5	19.5	132	0.911	25.2
	10	34.2	114	0.920	57.3
	20	38.9	102	0.922	62.5
	50	43.8	95.1	0.923	66.7
	100	60.3	87.3	0.918	75.8
	200	83.4	72.4	0.965	82.5
	400	90.7	66.1	0.988	83.9
	600	110	51.8	0.976	86.7

Medium	Inhibitor Concentration (ppm)	E_corr (mV)	I_corr (mA cm^-2)	β_c	β_a	Inhibitor efficiency (IE %)
1.0 M HCl	Blank	-452	1.21	192	141	-
	5	-449	0.716	`198	147	40.8
	10	-442	0.642	201	144	46.9
	20	-458	0.567	199	149	53.1
	50	-453	0.474	203	145	60.8
	100	-460	0.216	207	148	82.1
	200	-456	0.199	198	152	83.5
	400	-464	0.166	202	157	86.2
	600	-469	0.129	207	143	89.4
0.5 M H₂SO₄	Blank	-458	2.93	227	155	-
	5	-463	2.165	218	161	26.1
	10	-465	1.266	212	152	56.8
	20	-468	1.089	215	151	62.8
	50	-472	1.01	220	157	65.7
	100	-475	0.738	216	152	74.8
	200	-461	0.545	219	156	81.4
	400	-463	0.501	224	161	82.9
	600	-459	0.407	229	167	86.1

Medium	E_ocp (mV)	PZC (mV)	Excess Charge
1.0 M HCl	-452	-470	+
1M HCl + 50 ppm of inhibitor	-462	-510	+
0.5M H₂SO₄	-458	-600	+
0.5MH₂SO₄+ 50 ppm of inhibitor	-460	-580	+

[1] *e-mail: cvabavani@gmail.com

Brasil

Brasil

Colocid Dye - A Potential Corrosion Inhibitor for the Corrosion of Mild Steel in Acid Media