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

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 x C y H 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 x C y H 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 x C y H z film, even though its thickness is less than this.

Soft polymerization of hexamethyldisiloxane by coupling pulsed direct‐liquid injections with dielectric barrier discharge

“…In this structure, as illustrated in Figure 10, the -Si-CH 2 -Sibond represents one of the cross-linking points of the long siloxane chains. [76,77] However, the identification of this group in the FTIR spectra is difficult due to the strong absorption in the same wavenumber related to siloxane. [78] Other F I G U R E 9 (a) Variation of the Si-O-Si peak position and (b) Si-(CH 3 ) 2 -to-Si-(CH 3 ) 3 band ratio recorded for a total process time of 4 min as a function of the energy parameter obtained for various plasma deposition times and continuous carrier gas flow rates (full squares).…”

“…[56] possibilities of cross-linking occur by means of the formation of Si-Si and Si-O-Si bonds. [76,77] In all cases, the connection implies the loss of hydrogen atoms and/or methyl groups and hydrogen recombination (Si-H).…”

“…Hence, the specific set of plasma conditions appears to deliver sufficient energy to the HMDSO droplets and viscous films to break the weakest monomer bond, thereby enabling the molecule to react and polymerize in the droplet, but without providing the energy required to break higher energy bonds, in particular those leading to Si-CH 2 -Si, or any other kind of bridges. [76,77] In short, the monomer is not heavily fragmented, and the process leads to soft polymerization assisted by plasma in liquid droplets with very low cross-linking. At this stage of the study, it is however impossible to distinguish if polymerization occurs in the gas phase through filaments-droplets interactions and/or on the surface through plasmacoating interactions.…”

An infrared optical sensor for quantitative inline inspection of nanocoatings on plastic products

“…From literature it is known that the spectral shape of the reflection peak contains information on the stoichiometric composition of the material: Increasing oxygen content in SiOx (i.e., higher values of x) will shift the features towards higher frequencies. 10,11 Also a possible incorporation of carbon can cause spectral features 11 outside our scan range. An initial measurement on two samples that were produced via PE-CVD at varied oxygen flow rates did not show any significant spectral variations apart from the apparent drop in intensity (figure 4, lower panel).…”

Simulation study of organosilicon coating of a spherical nanoparticle immersed in a low-pressure HMDSO/O2 plasma

“…Deposition of silica-like SiO x and organosilicon SiO x C y H z thin films by plasma-enhanced chemical vapor deposition (PECVD) has attracted a lot of attention due to its prominent role in numerous technological applications [1][2][3][4][5]. These films are extensively used as gas permeation barrier coatings in food packaging [6][7][8][9][10][11][12], protective layers in the steel industry [13][14][15][16], and hydrophobic/superhydrophobic surfaces in automotive, textiles, and energy sectors [2][3][4]. One of the most frequently used precursors for the deposition of organosilicon films is hexamethyldisiloxane (HMDSO).…”