Effects of Aerobic and Anoxic Conditions on the Corrosion Behavior of NiCu Low Alloy Steel in the Simulated Groundwater Solutions

doi:10.1007/s40195-022-01490-8

Abstract

Abstract:

The present work focused on investigating the corrosion behavior of NiCu low alloy steel in 0.05 M NaHCO₃ solutions with different Cl⁻ concentrations under the aerobic-anoxic condition. The results showed that NiCu steel tended to be pseudo-passivated in the solutions of 0.05 M NaHCO₃ and 0.05 M NaHCO₃ + 0.01 M NaCl exposed to air. The cathodic process transformed from oxygen reduction to the common reduction of oxygen and α-FeOOH, while the anodic process was the iron dissolution. As Cl⁻ increased to 0.1 M, the steel tended to be activity dissolution. Due to the blocking effect of rust layer on the oxygen, the cathodic process transformed to the reduction of α-FeOOH. After the solutions were deoxidized, the cathodic process was controlled by only rust reduction. Meanwhile, both the cathodic process and anodic process of NiCu steel corrosion were significantly inhibited. During the whole aerobic-anoxic immersion, the corrosion rate of NiCu steel increased with Cl⁻ concentration. It was not only related to the promotion of Cl⁻ on the anodic dissolution of steel, but also related to the cathodic reduction of more α-FeOOH generated, which could accelerate the cathodic process.

Key words: Low alloy steel, Aerobic-anoxic condition, Corrosion behavior, Corrosion products, Electrochemical measurements

Xin Wei, Yupeng Sun, Junhua Dong, Nan Chen, Qiying Ren, Wei Ke. Effects of Aerobic and Anoxic Conditions on the Corrosion Behavior of NiCu Low Alloy Steel in the Simulated Groundwater Solutions[J]. Acta Metallurgica Sinica (English Letters), 2023, 36(5): 745-757.

Figures/Tables 15

References 44

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No	Electrode reaction	Equilibrium potential equation (vs. SCE)	E (V vs. SCE)
5	${\text{O}}_{{2}} \, + \,{\text{4e}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, \to \,{\text{4OH}}^{ - }$	E = 0.9852 − 0.05916 pH + 0.01479 lgPO₂	0.4924
6	${\text{2H}}^{ + } \, + \,{\text{2e}}\, \to \,{\text{H}}_{{2}}$	E = − 0.2438 − 0.05916 pH + 0.02958 lgPH₂	− 0.7366
7	${\text{2Fe}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{HCO}}_{{3}}^{ - } \, \to \,{\text{Fe}}_{{2}} \left( {{\text{OH}}} \right)_{{2}} {\text{CO}}_{{3}} \, + \,{\text{3H}}^{ + } \, + \,{\text{4e}}$	E = − 0.5220 − 0.04437 pH − 0.01479 lg[HCO₃⁻]	− 0.9120
8	${\text{3Fe}}_{{2}} \left( {{\text{OH}}} \right)_{{2}} {\text{CO}}_{{3}} \, + \,{\text{6H}}_{{2}} {\text{O}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, + \,{\text{2HCO}}_{{3}}^{ - } \, + \,{\text{4H}}^{ + } \, + \,{\text{2e}}$	E = 0.3177 − 0.11832 pH + 0.05916 lg[HCO₃⁻]	− 0.7496
9	${\text{6Fe}}\, + \,{\text{12H}}_{{2}} {\text{O}}\, + \,{\text{HCO}}_{{3}}^{ - } \, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, + \,{\text{13H}}^{ + } \, + \,{\text{14e}}$	E = − 0.4021 − 0.05493 pH − 0.004226 lg[HCO₃⁻]	− 0.8655
10	${\text{3Fe}}\, + \,{\text{4H}}_{{2}} {\text{O}}\, \to \,{\text{Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{8H}}^{ + } \, + \,{\text{8e}}$	E = − 0.3304 − 0.05916 pH	− 0.8232
11	${\text{Fe}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, \to \,\alpha - {\text{FeOOH}}\, + \,{\text{3H}}^{ + } \, + \,{\text{3e}}$	E = − 0.2658 − 0.05916 pH	− 0.7586
12	${\text{Fe}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, \to \,{\text{Fe}}\left( {{\text{OH}}} \right)_{{2}} \, + \,{\text{2H}}^{ + } \, + \,{\text{2e}}$	E = − 0.3072 − 0.05916 pH	− 0.8000
13	${\text{Fe}}\left( {{\text{OH}}} \right)_{{2}} \, \to \,\alpha - {\text{FeOOH}}\, + \,{\text{H}}^{ + } \, + \,{\text{e}}$	E = − 0.1830 − 0.05916 pH	− 0.6758
14	${\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, \to \,{5}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{2} + }} \, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{2H}}^{ + } \, + \,{\text{3e}}$	E = 0.1121 − 0.03944 pH + 0.01972 lg[HCO₃⁻] + 0.01972 lg[Fe²⁺]	− 0.3423
15	${\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, \to \,{6}\alpha - {\text{FeOOH}}\, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{5H}}^{ + } \, + \,{\text{4e}}$	E = 0.1696 − 0.07395 pH + 0.01479 lg[HCO₃⁻]	− 0.4668
16	${\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, \to \,{\text{2Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{4H}}_{{2}} {\text{O}}\, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{3H}}^{ + } \, + \,{\text{2e}}$	E = 0.1709 − 0.08874 pH + 0.02958 lg[HCO₃⁻]	− 0.6092
17	${8}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{3} + }} \, + \,{\text{3e}}\, \to \,{\text{3Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{4H}}_{{2}} {\text{O}}$	E = 0.2569 + 0.01972 lg[Fe³⁺]	0.1583
18	${8}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{2} + }} \, + \,{\text{2e}}\, \to \,{\text{3Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{4H}}_{{2}} {\text{O}}$	E = 0.1227 + 0.02958 lg[Fe²⁺]	− 0.0252
19	${3}\alpha - {\text{FeOOH}}\, + \,{\text{H}}^{ + } \, + \,{\text{e}}\, \to \,{\text{Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{2H}}_{{2}} {\text{O}}$	E = 0.2511 − 0.05916 pH	− 0.2417
20	$\begin{gathered} {5}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{3} + }} \, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{2H}}^{ + } \hfill \\ \, + \,{\text{4e}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \hfill \\ \end{gathered}$	E = 0.2153 − 0.02958 pH + 0.01479 lg[HCO₃⁻] + 0.01479 lg[Fe³⁺]	− 0.1255
2	${5}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{2} + }} \, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{2H}}^{ + } \, + \,{\text{3e}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}}$	E = 0.1121 − 0.03944 pH + 0.01972 lg[HCO₃⁻] + 0.01972 lg[Fe²⁺]	− 0.3423
22	${6}\alpha - {\text{FeOOH}}\, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{5H}}^{ + } \, + \,{\text{4e}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}}$	E = 0.1696 − 0.07395 pH + 0.01479 lg[HCO₃⁻]	− 0.4668
23	${\text{Fe}}\, + \,{\text{HCO}}_{{3}}^{ - } \, \to \,{\text{FeCO}}_{{3}} \, + \,{\text{H}}^{ + } \, + \,{\text{2e}}$	E = − 0.4136 − 0.02958 pH + 0.02958 lg[HCO₃⁻]	− 0.7009

No	Electrode reaction	Equilibrium potential equation (vs. SCE)	E (V vs. SCE)
5	${\text{O}}_{{2}} \, + \,{\text{4e}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, \to \,{\text{4OH}}^{ - }$	E = 0.9852 − 0.05916 pH + 0.01479 lgPO₂	0.4924
6	${\text{2H}}^{ + } \, + \,{\text{2e}}\, \to \,{\text{H}}_{{2}}$	E = − 0.2438 − 0.05916 pH + 0.02958 lgPH₂	− 0.7366
7	${\text{2Fe}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{HCO}}_{{3}}^{ - } \, \to \,{\text{Fe}}_{{2}} \left( {{\text{OH}}} \right)_{{2}} {\text{CO}}_{{3}} \, + \,{\text{3H}}^{ + } \, + \,{\text{4e}}$	E = − 0.5220 − 0.04437 pH − 0.01479 lg[HCO₃⁻]	− 0.9120
8	${\text{3Fe}}_{{2}} \left( {{\text{OH}}} \right)_{{2}} {\text{CO}}_{{3}} \, + \,{\text{6H}}_{{2}} {\text{O}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, + \,{\text{2HCO}}_{{3}}^{ - } \, + \,{\text{4H}}^{ + } \, + \,{\text{2e}}$	E = 0.3177 − 0.11832 pH + 0.05916 lg[HCO₃⁻]	− 0.7496
9	${\text{6Fe}}\, + \,{\text{12H}}_{{2}} {\text{O}}\, + \,{\text{HCO}}_{{3}}^{ - } \, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, + \,{\text{13H}}^{ + } \, + \,{\text{14e}}$	E = − 0.4021 − 0.05493 pH − 0.004226 lg[HCO₃⁻]	− 0.8655
10	${\text{3Fe}}\, + \,{\text{4H}}_{{2}} {\text{O}}\, \to \,{\text{Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{8H}}^{ + } \, + \,{\text{8e}}$	E = − 0.3304 − 0.05916 pH	− 0.8232
11	${\text{Fe}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, \to \,\alpha - {\text{FeOOH}}\, + \,{\text{3H}}^{ + } \, + \,{\text{3e}}$	E = − 0.2658 − 0.05916 pH	− 0.7586
12	${\text{Fe}}\, + \,{\text{2H}}_{{2}} {\text{O}}\, \to \,{\text{Fe}}\left( {{\text{OH}}} \right)_{{2}} \, + \,{\text{2H}}^{ + } \, + \,{\text{2e}}$	E = − 0.3072 − 0.05916 pH	− 0.8000
13	${\text{Fe}}\left( {{\text{OH}}} \right)_{{2}} \, \to \,\alpha - {\text{FeOOH}}\, + \,{\text{H}}^{ + } \, + \,{\text{e}}$	E = − 0.1830 − 0.05916 pH	− 0.6758
14	${\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, \to \,{5}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{2} + }} \, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{2H}}^{ + } \, + \,{\text{3e}}$	E = 0.1121 − 0.03944 pH + 0.01972 lg[HCO₃⁻] + 0.01972 lg[Fe²⁺]	− 0.3423
15	${\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, \to \,{6}\alpha - {\text{FeOOH}}\, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{5H}}^{ + } \, + \,{\text{4e}}$	E = 0.1696 − 0.07395 pH + 0.01479 lg[HCO₃⁻]	− 0.4668
16	${\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \, \to \,{\text{2Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{4H}}_{{2}} {\text{O}}\, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{3H}}^{ + } \, + \,{\text{2e}}$	E = 0.1709 − 0.08874 pH + 0.02958 lg[HCO₃⁻]	− 0.6092
17	${8}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{3} + }} \, + \,{\text{3e}}\, \to \,{\text{3Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{4H}}_{{2}} {\text{O}}$	E = 0.2569 + 0.01972 lg[Fe³⁺]	0.1583
18	${8}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{2} + }} \, + \,{\text{2e}}\, \to \,{\text{3Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{4H}}_{{2}} {\text{O}}$	E = 0.1227 + 0.02958 lg[Fe²⁺]	− 0.0252
19	${3}\alpha - {\text{FeOOH}}\, + \,{\text{H}}^{ + } \, + \,{\text{e}}\, \to \,{\text{Fe}}_{{3}} {\text{O}}_{{4}} \, + \,{\text{2H}}_{{2}} {\text{O}}$	E = 0.2511 − 0.05916 pH	− 0.2417
20	$\begin{gathered} {5}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{3} + }} \, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{2H}}^{ + } \hfill \\ \, + \,{\text{4e}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}} \hfill \\ \end{gathered}$	E = 0.2153 − 0.02958 pH + 0.01479 lg[HCO₃⁻] + 0.01479 lg[Fe³⁺]	− 0.1255
2	${5}\alpha - {\text{FeOOH}}\, + \,{\text{Fe}}^{{{2} + }} \, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{2H}}_{{2}} {\text{O}}\, + \,{\text{2H}}^{ + } \, + \,{\text{3e}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}}$	E = 0.1121 − 0.03944 pH + 0.01972 lg[HCO₃⁻] + 0.01972 lg[Fe²⁺]	− 0.3423
22	${6}\alpha - {\text{FeOOH}}\, + \,{\text{HCO}}_{{3}}^{ - } \, + \,{\text{5H}}^{ + } \, + \,{\text{4e}}\, \to \,{\text{Fe}}_{{6}} \left( {{\text{OH}}} \right)_{{{12}}} {\text{CO}}_{{3}}$	E = 0.1696 − 0.07395 pH + 0.01479 lg[HCO₃⁻]	− 0.4668
23	${\text{Fe}}\, + \,{\text{HCO}}_{{3}}^{ - } \, \to \,{\text{FeCO}}_{{3}} \, + \,{\text{H}}^{ + } \, + \,{\text{2e}}$	E = − 0.4136 − 0.02958 pH + 0.02958 lg[HCO₃⁻]	− 0.7009

Time (day)		R_s (Ω cm²)	Y_0−r (S sⁿ cm⁻²)	n_r	R_r (Ω cm²)	Y_0−o (S sⁿ cm⁻²)	n_o	R_o (Ω cm²)	Y_0−W (S s^0.5 cm⁻²)	Y_0−dl (S sⁿ cm⁻²)	n_dl	R_ct (Ω cm²)
Aerobic stage	Initial	92.7	-	-	-	4.1 × 10^-4	1	21.6	0.026	3.8 × 10^-4	0.87	2034
	13	59.5	1.6 × 10^-5	0.57	1645	2.9 × 10^-5	0.99	237	0.0029	8.6 × 10^-4	0.98	11,470
	20	58.6	4.9 × 10^-4	0.16	462	1.9 × 10^-4	0.90	186	0.0044	0.013	0.63	4265
Anoxic stage	9	50.2	0.013	0.35	423	-	-	-	-	0.013	0.66	4841
	33	54.7	0.0068	0.32	563	-	-	-	-	0.015	0.66	5735
	55	60.1	0.0052	0.30	758	-	-	-	-	0.014	0.71	9486
	80	78.8	0.0046	0.26	1128	-	-	-	-	0.012	0.60	15,640

Time (day)		R_s (Ω cm²)	Y_0−r (S sⁿ cm⁻²)	n_r	R_r (Ω cm²)	Y_0−o (S sⁿ cm⁻²)	n_o	R_o (Ω cm²)	Y_0−W (S s^0.5 cm⁻²)	Y_0−dl (S sⁿ cm⁻²)	n_dl	R_ct (Ω cm²)
Aerobic stage	Initial	92.7	-	-	-	4.1 × 10^-4	1	21.6	0.026	3.8 × 10^-4	0.87	2034
	13	59.5	1.6 × 10^-5	0.57	1645	2.9 × 10^-5	0.99	237	0.0029	8.6 × 10^-4	0.98	11,470
	20	58.6	4.9 × 10^-4	0.16	462	1.9 × 10^-4	0.90	186	0.0044	0.013	0.63	4265
Anoxic stage	9	50.2	0.013	0.35	423	-	-	-	-	0.013	0.66	4841
	33	54.7	0.0068	0.32	563	-	-	-	-	0.015	0.66	5735
	55	60.1	0.0052	0.30	758	-	-	-	-	0.014	0.71	9486
	80	78.8	0.0046	0.26	1128	-	-	-	-	0.012	0.60	15,640

Time (day)		R_s (Ω cm²)	Y_0-r (S sⁿ cm⁻²)	n_r	R_r (Ω cm²)	Y_0-o (S sⁿ cm⁻²)	n_o	R_o (Ω cm²)	Y_0-W (S s^0.5 cm⁻²)	Y_0-dl (S sⁿ cm⁻²)	n_dl	R_ct (Ω cm²)
Aerobic stage	Initial	61.1	-	-	-	0.019	0.43	34	0.027	0.0008	0.76	1225
	10	38.7	0.0076	0.86	631	0.0046	0.98	281	0.0076	0.038	0.98	4981
	20	36.7	0.0049	0.23	166	0.0055	0.93	187	0.0092	0.014	0.78	3539
Anoxic stage	13	33.1	0.0052	0.62	394	-	-	-	-	0.019	0.9	4508
	31	37.4	0.0044	0.64	179	-	-	-	-	0.010	0.72	3560
	55	47.8	0.0028	0.59	364	-	-	-	-	0.011	0.83	8632
	80	59.2	0.0023	0.59	202	-	-	-	-	0.0076	0.57	7980