25 research outputs found
Improvement in corrosion resistance of AZ91D Mg alloy in simulated body fluid by cerium-based/stearic acid composite coatings
No full textMagnesium alloys have attracted attention due to their biocompatibility and biodegradability.In this work, composite coatings are developed to potentially improve the corrosion resistanceof AZ91D Mg alloy in simulated physiological fluid. Cerium-based/stearic acid coatings wereprepared by electrodeposition combined with a simple immersion method. The effect of stearicacid bath concentration on the contact angle and corrosion resistance of the composite coatingswas evaluated. The results showed that the stearic acid treatment increased the hydrophobicityof the surfaces of the cerium-based simple coatings. The use of an appropriate stearic acidconcentration is a key for the fabrication of hydrophobic surfaces. The duplex coatings weredemonstrated to protect the substrate from corrosion in Ringer solution.Fil: Loperena, Ana Paula. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Saidman, Silvana Beatriz. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Lehr, Ivana Leticia. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin
The effect of PPY powder on the anticorrosive performance of a duplex cerium/epoxy coating
No full textPolypyrrole powder was chemically synthesized using cerium tartrate as an oxidant. The powder was loaded into an epoxy resin to create a protective coating onto AZ91D Mg alloy. The coatings consisted of an inner cerium-based film and an epoxy layer loaded with different amounts of polypyrrole (0.2–5 wt%) on top. Infrared spectroscopy and Energy Dispersive X-Ray spectroscopy analysis were used to characterize the polymer powder. The anticorrosive properties of the coatings were studied in NaCl containing solution by applying electrochemical measurements such as polarization, electrochemical impedance spectroscopy (EIS), and open circuit potential (OCP). Solution analysis was done to check the electrochemical results obtained. The corrosion resistance was remarkably improved by the addition of the polypyrrole. The best anticorrosive properties were achieved when the epoxy layer was loaded with 1 wt% of PPy. The results show a decrease in corrosion current density from 2.763 × 10-6 to 2.770 × 10-7 mA cm-2 when the polymer was loaded. In addition, the filler reduces the water absorption of the epoxy coating from 9 to 7%. The protective properties were attributed to the barrier behavior of the epoxy film, the corrosion inhibition effect of the PPy, and the self-healing effect of the cerium compounds present in the PPy powder.Fil: Loperena, Ana Paula. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Lehr, Ivana Leticia. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Saidman, Silvana Beatriz. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin
Amperometric detection of D-sorbitol with NAD+-D-sorbitol dehydrogenase modified carbon paste electrode
No full textA biosensor based on modified carbon paste electrodes for the amperometric detection of D-sorbitol is described. Carbon paste electrodes were modified by D-sorbitol dehydrogenase (SDH) and nicotinamide adenine dinucleotide (NAD+) and coated with a non-conducting poly(o-phenylenediamine) (PPD) film. After partial oxidation of the immobilised NAD+ by applying a potential step f rom 0.0 to 1.2 V (SCE), the modified electrode allowed the amperometric detection of the NADH enzymatically obtained at an applied potential of 0.0 V. The resulting biosensor responded rapidly to sorbitol up to 8 x 10-4 M with a detection limit of 4 x 10-5 M.Fil: Saidman, Silvana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Lobo Castañón, M.J.. Universidad de Oviedo; EspañaFil: Miranda Ordieres, A.J.. Universidad de Oviedo; EspañaFil: Tuñón Blanco, P.. Universidad de Oviedo; Españ
Immobilization of antibacterial metallic cations (Ga 3+ , Zn 2+ and Co 2+ ) in a polypyrrole coating formed on Nitinol
No full textGallium, zinc and cobalt species were immobilized in hollow rectangular-sectioned microtubes of polypyrrole(PPy) electrosynthesized on Nitinol (NiTi) alloy by means of two different methods. One of them involved theimmobilization after the PPy electropolymerization and the other one during the electrosynthesis process. Theantibacterial activity of the coating against Escherichia coli (E. coli) was evaluated and the best results wereobtained with gallium species. Characterization results demonstrated that gallium is incorporated into the PPymatrix as Ga3+ ions. The PPy film with gallium species incorporated during the electropolymerization exhibiteda good corrosion protection performance.Fil: Saugo, Melisa. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Brugnoni, Lorena Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Flamini, Daniel Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Saidman, Silvana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentin
Electrodeposition study of polypyrrole-heparin and polypyrrole-salicylate coatings on Nitinol
No full textPolypyrrole (PPy) films containing heparin (Hep), salicylate (Sa) or both anions were electrochemicallydeposited as single layers or bilayers onto Nitinol (NiTi) alloy. The PPy deposition onto the bare alloy wasachieved through an anodic electropolymerization in the presence of the anions. The aim of this studywas to determine the influence of the electrosynthesis parameters (electrolyte nature and monomer andelectrolyte concentrations) on the electroforming mechanism and morphology of the PPy. The PPycoating containing Hep and Sa not only presents a very good anticoagulant activity but also presentsexcellent anticorrosive properties in Ringer´s solution.Fil: Flamini, Daniel Omar. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Valle, M.I.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Sandoval, Marisa Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Massheimer, Virginia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Saidman, Silvana Beatriz. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentin
Immobilization of Zn species in a polypyrrole matrix to prevent corrosion and microbial growth on Ti-6Al-4V alloy for biomedical applications
No full textPolypyrrole (PPy) films were potentiostatically synthesized from an aqueous solution containing sodium salicylate (NaSa) on Ti-6Al-4 V alloy. In order to develop a coating to prevent corrosion and microbial growth on the alloy, the microstructured polymer matrix was employed for the immobilization of Zn species by means of two different methods. One of them involved the immobilization after the PPy electropolymerization (method 1) and the other one during the electrosynthesis process (method 2). The antimicrobial activity against Candida albicans and Staphylococcus aureus was evaluated. Only the coating obtained by method 2 showed antibacterial activity against S. aureus.To verify the acceptability of the coated samples for dental implant applications, the anticorrosive properties were evaluated by different electrochemical techniques (open circuit potential (OCP), linear sweep voltammetry (LSV), chronoamperometry (CA)) and electrochemical impedance spectroscopy (EIS) measurements). The electrolyte selected to simulate the intraoral condition was artificial saliva (AS) at pH 4 containing 0.20 % NaF. It was found that the electrode coated with unmodified and modified PPy showed a good corrosion protection behavior. The active dissolution process of the alloy was suppressed. Moreover, the coatings reduce the steady state current densities at 0.20 V (vs. saturated calomel electrode (SCE)) and decrease the release of Ti and V ions. No cracks or corrosion products were detected on the films after immersion in AS solution.Fil: Martínez, Alejandra Leonor. Ministerio de Ciencia. Tecnología e Innovación Productiva. Agencia Nacional de Promoción Científica y Tecnológica; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Brugnoni, Lorena Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Flamini, Daniel Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Saidman, Silvana Beatriz. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin
