Surface Morphological and Chemical Features of Anticorrosion ZrO2–TiO2 Coatings: Impact of Zirconium Precursor

Stambolova, I.; Stoyanova, D.; Shipochka, Мaria; Boshkova, Nelly; Eliyas, A.; Simeonova, Silviya; Grozev, Nikolay A.; Boshkov, N.

doi:10.3390/coatings11060703

Cited by 11 publications

(8 citation statements)

References 45 publications

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“…Similar results regarding the thermal behavior of chitosan were proved by other researchers [24,32]. The second stage is due to the dehydration of the zirconium organic precursor at about 190 • C with 1% mass loss [6].…”

Section: Resultssupporting

confidence: 87%

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Protective Efficiency of ZrO2/Chitosan “Sandwich” Coatings on Galvanized Low-Carbon Steel

et al. 2021

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Enhanced corrosion efficiency of low-carbon steel was achieved by newly developed hybrid multilayers, composed of low-carbon steel coated with an electrodeposited zinc sublayer (1 µm), a chitosan (CS) middle layer and ZrO2 coating by the sol–gel method (top-layer). The middle chitosan layer was obtained by dipping galvanized steel substrate in 3% tartatic acid water solution of medium molecular-weight chitosan, composed of β-(1–4)-linked D-glucosamine and N-acetyl-D-glucosamine with a deacetylation degree of about 75–85% (CS). The substrates were dipped into CS solution and withdrawn at a rate of 30 mm/min. One part of the samples with the CS layer was dried at room temperature for 2 weeks, and another part at 100 °C for 1 h, respectively. After CS deposition treatment, the substrates were dipped into an isopropanol sol of zirconium butoxide with small quantity of polyethylene glycol (PEG400). The dipping-drying cycles of the ZrO2 coatings were repeated three times. After the third cycle, the final structures were treated at 180 °C. The samples were denoted as T25, which consists of the CS middle layer, and dried at RT and T100 with the CS middle layer treated at 100 °C, respectively. The samples were characterized by means of differential thermal analysis (DTA-TG), XRD analyses, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Hydrophobicity properties were evaluated by measuring the contact angle with a ramé-hart automated goniometer. Two electrochemical tests—potentiodynamic polarization technique (PD) and electrochemical impedance spectroscopy (EIS)—have been used to determine the corrosion resistance and protective ability of the coatings in a 5% NaCl solution. The results obtained by both methods revealed that the applied “sandwich” multilayer systems demonstrate sacrificial character and will hopefully protect the steel substrate in corrosion medium containing chloride ions as corrosion activators. The newly obtained hybrid multilayer coating systems have dense structure and a hydrophobic nature. They demonstrated positive effects on the corrosion behavior at conditions of external polarization independent of their various characteristics: morphology, grain sizes, surface roughness and contact angle. They extend the service life of galvanized steel in a chloride-containing corrosion medium due to their amorphous structure, hydrophobic surface and the combination of the positive features of both the chitosan middle layer and the zirconia top layer.

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Section: Resultssupporting

confidence: 87%

“…The protective effect of the zinc can be significantly increased by additional surface treatment to form various types of protective films-conversion, sol-gel, etc. [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Protective Efficiency of ZrO2/Chitosan “Sandwich” Coatings on Galvanized Low-Carbon Steel

et al. 2021

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“…Diffraction patterns shown in Figure 5 of the AM60-AlN and AM60 substrates, before and after being coated with the hybrid PS-ZrO 2 , did not reveal the presence of crystalline structure in the hybrid material; the characteristic peaks of Mg, Al-Mn, and β-Mg 17 Al 12 have been previously detected and reported [13]. It has been suggested that if the ZrO 2 is present as an amorphous phase, it could reduce the sites for the diffusion of the Cl − ions through such film and, thereby, improve the corrosion resistance of the metal substrate [73].…”

Section: Xrd Analysismentioning

confidence: 88%

Hybrid Coating of Polystyrene–ZrO2 for Corrosion Protection of AM Magnesium Alloys

et al. 2023

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A hybrid material of polystyrene (PS)–ZrO2 was developed by the sol–gel technique and deposited by spin-coating on AM60 and AM60–AlN nanocomposite surfaces to enhance corrosion resistance in marine environments. PS–ZrO2 with an average thickness of ≈305 ± 20 nm was dispersed homogeneously, presenting isolated micro–nano-structure defects with air trapped inside, which led to an increase in roughness (≈4 times). The wettability of the coated substrates was close to the hydrophobic border (θCA=90°–94°). The coated samples were exposed for 30 days to SME solution, simulating the marine–coastal ambience. The initial pH = 7.94 of the SME shifted to more alkaline pH ≈ 8.54, suggesting the corrosion of the Mg matrix through the coating defects. In the meantime, the release of Mg2+ from the PS–ZrO2-coated alloy surfaces was reduced by ≈90% compared to that of non-coated. Localized pitting attacks occurred in the vicinity of Al–Mn and β-Mg17Al12 cathodic particles characteristic of the Mg matrix. The depth of penetration (≈23 µm) was reduced by ≈85% compared to that of non-coated substrates. The protective effect against Cl ions, attributed to the hybrid PS–ZrO2-coated AM60 and AM60–AlN surfaces, was confirmed by the increase in their polarization resistance (Rp) in 37% and 22%, respectively, calculated from EIS data.

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“…Two well-known electrochemical methods were applied to estimate the corrosion behavior of the sample systems: potentiodynamic (PDP) polarisation curves and polarisation resistance (R p ) measurements. Detailed description of these techniques and devices have been reported by the authors previously [5][6][7]16]. The investigations were realized in a three-electrode electrochemical cell having a volume of 300 mL.…”

Section: Electrochemical Testsmentioning

confidence: 99%

“…Romero et al have successfully applied spray pyrolysis for deposition of various inorganic oxide films such as NiO, MgO [13], ZrO 2 [14] or ZnO [15], having an aim to improve the protective characteristics of the galvanized steel. The effective protection of galvanized steel in comparison to the uncoated galvanized one has also been proved by the application of selected inorganic oxide coatings [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Protective Characteristics of TiO2 Sol-Gel Layer Deposited on Zn-Ni or Zn-Co Substrates

et al. 2023

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This study aimed to present the differences in the corrosion properties and protective ability of two bi-layer systems obtained on low-carbon steel in a model corrosive medium of 5% NaCl solution. These newly developed systems consist of Zn-Co (3 wt.%) or Zn-Ni (10 wt.%) alloy coatings as under-layers and a very thin TiO2 sol-gel film as a top-layer. Scanning electron microscopy (SEM) is used for characterization of the surface morphology of the samples indicating that some quantitative differences appear as a result of the different composition of both zinc alloys. Surface topography is investigated by means of atomic force microscopy (AFM), and the hydrophobic properties are studied by contact angle (CA) measurements. These investigations demonstrate that both sample types possess grain nanometric surface morphology and that the contact angle decreases very slightly. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used for characterization of the chemical composition and electronic structure of the samples. The roughness Rq of the Zn-Ni/TiO2 is 49.5 nm, while for Zn-Co/TiO2, the Rq value is 53.4 nm. The water contact angels are 93.2 and 95.5 for the Zn-Ni/TiO2 and Zn-Co/TiO2 systems, respectively. These investigations also show that the co-deposition of Zn and Ni forms a coating consisting entirely of Ni2Zn11, while the other alloy contains Zn, Co and the intermetallic compound CoZn13. The corrosion resistance and protective ability are estimated by potentiodynamic polarization (PDP) curves, as well as polarization resistance (Rp) measurements for a prolonged test period (35 days). The results obtained are compared with the corrosion characteristics of ordinary zinc coating with an equal thickness. The experimental data presents the positive influence of the newly developed systems on the enhanced protective properties of low-carbon steel in a test environment causing a localized corrosion—lower corrosion current density of about one magnitude of order (~10−6 A.cm−2 for both systems and ~10−5 A.cm−2 for Zn) and an enhanced protective ability after 35 days (~10,000–17,000 ohms for the systems and ~900 ohms for Zn).

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Surface Morphological and Chemical Features of Anticorrosion ZrO2–TiO2 Coatings: Impact of Zirconium Precursor

Cited by 11 publications

References 45 publications

Protective Efficiency of ZrO2/Chitosan “Sandwich” Coatings on Galvanized Low-Carbon Steel

Protective Efficiency of ZrO2/Chitosan “Sandwich” Coatings on Galvanized Low-Carbon Steel

Hybrid Coating of Polystyrene–ZrO2 for Corrosion Protection of AM Magnesium Alloys

Protective Characteristics of TiO2 Sol-Gel Layer Deposited on Zn-Ni or Zn-Co Substrates

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