Evaluation of mechanically treated cerium (IV) oxides as corrosion inhibitors for galvanized steel (original) (raw)
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Progress in Organic Coatings, 2012
The effectiveness of mechanically treated CeO 2 particles and SiO 2 particles as active fillers into an organic coating was investigated. For this purpose, different combinations of CeO 2 and SiO 2 particles were added to an epoxy-polyester polymeric matrix: mechanically treated CeO 2 particles, mechanically treated CeO 2 /SiO 2 particles and mechanically treated SiO 2 powders (used for comparison). The particles were dispersed into the polymeric matrix and HDG steel panels were coated with the different paints. A strontium chromates containing paint was used as a reference to compare the performances of the other samples. The salt spray results proved the good performance of coatings containing combinations of ceria and silica especially where these had been mechanically treated in a co-milling operation. The paint containing only the mechanically treated SiO 2 particles showed a fairly good resistance in the salt spray chamber considering the scratched samples. The EIS measurements evidenced the good corrosion protection properties of the paints containing the different combinations of mechanically treated CeO 2 and SiO 2 particles. After about 1000 h of immersion in 0.1 M NaCl solution, the samples containing the mix of mechanically treated CeO 2 /SiO 2 particles showed impedance values which were comparable with the chromate control sample. The cathodic polarization tests evidenced the low extent of detachment of the coating containing the mix of mechanically treated CeO 2 /SiO 2 particles. The electrochemical characterization and neutral salt spray test results proved the effectiveness of the mechanical treated cerium (IV) oxides treated together with SiO 2 as active pigments to improve the corrosion protection of the substrate. The reasons for the synergistic effect of the milled (together or separately) SiO 2 and CeO 2 particles was not clear at all, but a few hypothesis were discussed.
Electrochemical study of the corrosion inhibition effect of CeO2 nanoparticles
The paper aims to provide some insight into the fundamental mechanisms for the behavior of cerium oxides nanoparticles as corrosion inhibitors for steel. The work was carried out on mild steel water based dispersions of cerium oxides nanoparticles in presence of both, sulfates and chlorides. Ceria nanoparticles were produced via precipitation of cerium Ce(NO 3 ) 3 .6H 2 O in water, particles of about 70 nm hydrodynamic diameter were obtained. The analysis of the effectiveness of the ceria nanoparticles as corrosion inhibitors was performed by means of electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) versus time measurements. The experimental measurements suggested that cerium oxide affects the electrochemical properties of mild steel surface; they promoted an ennoblement effect and strong modifications in the impedance response.
Electrochimica Acta, 2013
The paper aims to provide some insight into the fundamental mechanisms for the behavior of cerium oxides nanoparticles as corrosion inhibitors for steel. The work was carried out on mild steel water based dispersions of cerium oxides nanoparticles in presence of both, sulfates and chlorides. Ceria nanoparticles were produced via precipitation of cerium Ce(NO 3 ) 3 .6H 2 O in water, particles of about 70 nm hydrodynamic diameter were obtained. The analysis of the effectiveness of the ceria nanoparticles as corrosion inhibitors was performed by means of electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) versus time measurements. The experimental measurements suggested that cerium oxide affects the electrochemical properties of mild steel surface; they promoted an ennoblement effect and strong modifications in the impedance response.
2011
This work is focused on the study of corrosion-protection ability of the thin ceria film, formed electrochemically on OC404 stainless steel (SS) in non-aqueous electrolytes. The influence of changes in the surface concentration of Ce 2 O 3-CeO 2 on the corrosion behaviour of OC404 stainless steel in 3.5% NaCl was investigated prior to the thermal treatment as well as after it. A shift of corrosion potential in positive direction was found via polarization curve recording, as well as via decrease in the corrosion current, respectively decrease in the corrosion rate (enhancement of the corrosion protection) in the presence of ceria oxide films. The data, acquired by AFM and XPS, are in a good agreement with these results. On the basis of the obtained results we can conclude that the presence of Ce 2 O 3-CeO 2 film results in passivation and re-passivation of the steel surface and a slowdown in the pitting corrosion in an aggressive media. These conclusions are explained by the strong polarization influence of the Ce 2 O 3-CeO 2 layers on the conjugated depolarization cathodic reaction of reduction of the dissolved oxygen.
Influence of CeO 2 nanoparticles on the corrosion behavior of electrodeposited Ni coatings
Nickel-Ceria (Ni-CeO 2) nanocomposite coatings were developed on mild steel (MS) substrate using electrodeposition method. The codeposition of the nanoparticles was achieved from the optimized Ni plating bath loaded with CeO 2 nanoparticles (particle size <20 nm). Ni and Ni-CeO 2 coatings were achieved at a wide current density (c.d.) range from 1.0 to 5.0 A/dm 2 under optimal conditions, and their corrosion protection efficacy was examined in 5% NaCl medium. The material property of Ni coatings towards corrosion was found to be enhanced by the incorporation of the distributed phase, CeO 2 nanoparticles, into the Ni matrix. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) techniques were used to examine the corrosion behaviors of metal and nanocomposite coatings. The obtained results showed an improvement in corrosion resistance for Ni-CeO 2 coatings compared with Ni, and the nanocomposite coating obtained at 4.0 A/dm 2 was found to be optimal with least corrosion rate (CR = 1.8 10 2 mm/y). The coatings have been characterized using diverse instrumental methodologies such as SEM, EDS and XRD study, and results are discussed.
Molecules, 2021
Novel Zn-Co-CeO2 protective composite coatings were deposited successfully from chloride plating solutions. Two different types of ceria sources were used and compared: commercial ceria powder and home-made ceria sol. Electrodeposition was performed by a direct current in the range of 1–8 A dm−2. Two different agitation modes were used and compared, magnetic stirring and ultrasound-assisted stirring (US). The influence of magnetic stirring on the stability of the related plating baths was evaluated via a dynamic scattering method. The results pointed to better stability of the prepared ceria sol. The morphology of the composite coatings was examined by scanning electron microscopy (SEM), and particle content was determined by energy-dispersive X-ray spectroscopy (EDS). The results showed that the increase in the deposition current density was not beneficial to the coating morphology and particle content. The corrosion behavior of the Zn-Co-CeO2 composite coatings was analyzed and co...
Metals, 2021
Electrodeposition and characterization of novel ceria-doped Zn-Co composite coatings was the main goal of this research. Electrodeposited composite coatings were compared to pure Zn-Co coatings obtained under the same conditions. The effect of two ceria sources, powder and home-made sol, on the morphology and corrosion resistance of the composite coatings was determined. During the electrodeposition process the plating solution was successfully agitated in an ultrasound bath. The source of the particles was found to influence the stability and dispersity of plating solutions. The application of ceria sol resulted in an increase of the ceria content in the resulting coating and favored the refinement from cauliflower-like morphology (Zn-Co) to uniform and compact coral-like structure (Zn-Co-CeO2 sol). The corrosion resistance of the composite coatings was enhanced compared to bare Zn-Co as evidenced by electrochemical impedance spectroscopy and scanning Kelvin probe results. Zn-Co do...
2014
Protective coatings have been deposited on electrogalvanized steel by immersion in solutions containing 2-Butyne-1.4-diol propoxylate (CHO), cerium nitrate, sodium nitrate and sodium sulphate for different immersion periods. The surface morphology and chemical composition of the coatings formed on the electrogalvanized steel were studied using field emission gun scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier Transform Infrared Spectroscopy. The corrosion resistance of the electrogalvanized steel prior to and after surface treatment was investigated by electrochemical impedance spectroscopy in 0.1 mol L NaCl solution. The results were compared to the performance of a chromate conversion coating in the same solution. The coatings formed on the electrogalvanized steel surface showed the presence of a mixed organic/inorganic layer containing CeO and CeO which improved the corrosion resistance of the substrate and showed a superior corrosion resistance to that...
the Chemical Technology, 2014
Conversion coatings are used not only to impart corrosion protection but also to improve adhesion of paint systems/ metal surface. Chromate-based converJosé Daniel Culcasi1, Cecilia Inés Elsner1,2, Alejandro Ramón Di Sarli2*, Luis Palomino3, Célia Regina Tomachuk4, Isolda Costa4 1Engineering School, National University of La Plata, Av. 1 Esq. 47. CP. B1900TAG, La Plata, (ARGENTINA) 2Research and Development Centre in Paint Technology (CICPBA-CCT CONICET LA PLATA); Av. 52 s/n entre 121 y 122. CP. B1900AYB, La Plata, (ARGENTINA) 3Polytechnic School of the University of San Pablo (EPUSP), Engineering Chemistry Department, Av. Prof. Lineu Prestes, 580, Caixa Postal 61548, CEP 05508-970, São Paulo-SP, (BRAZIL) 4Energy and Nuclear Research Institute, IPEN/CNEN-SP, CCTM, Av. Prof. Lineu Prestes, 2242, CEP 05508-000, São Paulo, SP, (BRAZIL) E-mail: ardisarli@cidepint.gov.ar; ardisarli@gmail.com; cielsner@ing.unlp.edu.ar; tomazuk@gmail.com