Effect of Plasma Oxidation Treatment on Production of a SiOx/SiOxCyHz Bilayer to Protect Carbon Steel Against Corrosion

Ribeiro, Rafael P.; Rangel, Rita de Cássia C.; Fernandes, Felipe O.; Cruz, Nilson C.; Rangel, Elidiane C.

doi:10.1590/1980-5373-MR-2021-0039

Acessibilidade / Reportar erro

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Article • Mat. Res. 24 (suppl. 1) • 2021 • https://doi.org/10.1590/1980-5373-MR-2021-0039 copy

Effect of Plasma Oxidation Treatment on Production of a SiOx/SiOxCyHz Bilayer to Protect Carbon Steel Against Corrosion

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

Because of its excellent properties, carbon steel is a material widely used in several sectors. However, it is easily corroded when exposed to the environment. Seeking to remedy this problem, the possibility of coating carbon steel with SiO_x/SiO_xC_yH_z films generated by deposition and oxidation in low-pressure plasmas was investigated. Specifically, the effects of excitation power of the oxidation plasma on layer thickness, chemical structure, elemental composition, and barrier properties of the obtained coatings were investigated. The coating of the steel with the SiO_xC_yH_z film, generated by plasma in an atmosphere of hexamethyldisiloxane (HMDSO), increased the total resistance to the passage of electric current, measured by electrochemical impedance spectroscopy. However, under the condition of moderate power oxidation (50 W), the results point to the creation of a bilayer system with high resistance to electrochemical attack compared to the SiO_xC_yH_z film, even though its thickness is less than this.

Keywords:
Carbon steel; corrosion resistance; SiO_xC_yH_z; SiO_x; PECVD; plasma oxidation

Sample\Component	Si-O₁ (%)	Si-O₂ (%)	Si-O₃ (%)	Si-O₄ (%)	Si-OH (%)
As-deposited	15	62	19	4	---
10 W	---	---	4	47	49
15 W	---	---	4	25	71
25 W	---	---	4	23	73
50 W	---	2	10	7	81
100 W	1	1	---	78	20
200 W	2	---	---	46	52
300 W	1	1	---	52	46

Sample	Rs (Ω.cm²)	Rcoat (Ω.cm²)	Ccoat-T (F cm^-2)	Ccoat-α	Rct (Ω.cm²)	Cdl-T (F cm^-2)	Cdl-α
Carbon steel	2.31	---	---	---	1.09x10³	5.86x10^-4	0.847
As deposited	2865	8.22x10⁴	1.44x10^-7	0.743	3.31x10⁶	8.44x10^-8	0.726
10 W	402.6	4.56x10³	1.30x10^-5	0.620	6.99x10⁴	3.37x10^-6	0.770
15 W	249.7	1.77x10²	2.29x10^-6	0.816	2.25x10⁵	6.66x10^-7	0.909
25 W	483	2.45x10⁴	1.75x10^-6	0.681	4.18x10⁵	1.49x10^-10	0.894
50 W	1456	7.36x10⁵	5.25x10^-9	0.839	1.24x10⁷	2.63x10^-8	0.572
100 W	723.3	1.18x10⁴	2.77x10^-7	0.727	8.27x10⁵	7.24x10^-7	0.688
200 W	364.2	1.09x10⁴	5.13x10^-7	0.662	1.51x10⁶	1.28x10^-6	0.673
300 W	989.7	1.67x10⁴	2.37x10^-6	0.698	3.60x10⁵	1.05x10^-6	0.727

Sample	Rs Error (%)	Rcoat Error (%)	Ccoat-T Error (%)	Ccoat-α Error ( %)	Rct Error (%)	Cdl-T Error (%)	Cdl-α Error (%)	GoF (χ²)
Carbon steel	1.5	---	---	---	1.9	1.5	0.4	4.4 x 10^-4
As deposited	4	2.6	4.2	4.3	3.2	0.8	0.6	2.91x10^-5
10 W	2	3.7	1.1	0.4	2.6	2.3	2.2	1.19x10^-4
15 W	1	1.8	0.4	2.1	0.5	0.2	0.6	4.19x10^-6
25 W	2	14.6	0.4	0.5	2.2	15	6.7	7.73x10^-5
50 W	9.3	5.8	3.2	2.3	8.9	3	4.8	4.20x10^-4
100 W	8	2.9	2.7	2.8	4.9	4	14.2	2.70x10^-4
200 W	17	3.4	3.9	3.3	12.9	3.2	10.9	7.07x10^-4
300 W	2	9.6	2.6	1.3	7	4.7	3.3	7.39x10^-4

ABM, ABC, ABPol UFSCar - Dep. de Engenharia de Materiais, Rod. Washington Luiz, km 235, 13565-905 - São Carlos - SP- Brasil. Tel (55 16) 3351-9487 - São Carlos - SP - Brazil
E-mail: pessan@ufscar.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] *e-mail: elidiane@sorocaba.unesp.br