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Electrochemical impedance spectroscopy was employed to evaluate protective performance of the solvent-borne epoxy coatings pigmented with zinc aluminum polyphosphate as a representative of phosphate-based anticorrosion compounds at different Lambda values. Furthermore, the effective ratio of the pigment volume concentration (PVC) to the critical pigment volume concentration (CPVC) was determined. To compare the function of zinc aluminum polyphosphate and zinc phosphate incorporated into coatings, electrochemical noise method as well as electrochemical impedance spectroscopy was taken into consideration. The trend and magnitude of charge transfer, coating and noise resistances plus the amplitude of the current noise fluctuation indicated superiority of the modified pigment. In order to provide an insight into the mechanism by which anticorrosion pigments improve protective behavior of coating, performance of bare metals exposed to pigment extracts was assessed through taking advantage of electrochemical impedance spectroscopy and electrochemical noise method as well. 相似文献
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R. Naderi 《Electrochimica acta》2009,54(27):6892-8733
This work intends to study inhibitive performance of organic and inorganic complexes of Zn(II) using electrochemical techniques along with surface analysis. In this regard, inorganic zinc aluminum polyphosphate pigment as modified zinc phosphate and zinc acetylacetonate and benzimidazole mixture representing organic replacement of zinc phosphate were employed. Through taking advantage of electrochemical impedance spectroscopy and DC polarization, two mentioned approaches were indicated to be efficient. Charge transfer resistance and corrosion current density values exhibited superiority of zinc aluminum polyphosphate and mixture of zinc acetylacetonate and benzimidazole compared to zinc phosphate and also zinc acetylacetonate and benzimidazole as individual inhibitors. Corrosion inhibition efficiencies calculated based on charge transfer resistance in consistent with those calculated from corrosion current density showed the following sequence; zinc aluminum polyphosphate > mixture of zinc acetylacetonate and benzimidazole > zinc acetylacetonate > zinc phosphate > benzimidazole. Showing film formation, surface analysis SEM/EDX confirmed the results obtained by electrochemical methods. 相似文献
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Protective performance of the epoxy primer containing strontium aluminum polyphosphate (SAPP) as a zinc-free phosphate-based anticorrosion pigment is aimed to assess in this work through taking advantage of electrochemical impedance spectroscopy (EIS) and electrochemical noise method (ENM). The absence of zinc offers an excellent environmentally friendly profile to the class of inhibiting compound. In the pigment extracts, the electrochemical techniques revealed superiority of SAPP compared to the conventional zinc phosphate (ZP). The behavior was connected to precipitation of a protective layer on the surface exposed to SAPP. In comparison with ZP, the most effective SAPP content in the protective primer was then determined using EIS. 相似文献
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S.M. Mousavifard P. MalekMohammadi Nouri M.M. Attar B. Ramezanzadeh 《Journal of Industrial and Engineering Chemistry》2013,19(3):1031-1039
The epoxy/polyamide coating was loaded with different pigment mixtures of the zinc phosphate (ZP), zinc aluminum phosphate (ZPA) and zinc aluminum polyphosphate (ZAPP) pigments. The electrochemical impedance spectroscopy (EIS) and salt spray test were used to investigate corrosion inhibition performance of the coatings. The adhesion strengths of the coatings were measured by a pull-off test. Results revealed lower coating pull-off strength loss when the ZPA and ZAPP pigments were used. A significant decrease in number of blisters together with low pull-off strength loss and best corrosion inhibition properties were observed when the mixture of 80:20 of ZAPP:ZPA was used. 相似文献
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Epoxy/polyamide coatings were loaded with different mixtures of strontium aluminum polyphosphate (SAPP) and zinc aluminum phosphate (ZPA) pigments. Moreover, a coating containing zinc phosphate (ZP) was prepared as a reference sample. The coatings were applied on St-37 steel substrates and then were exposed to 3.5 wt% NaCl solution up to 35 days. The corrosion inhibition properties of the pigments extracts were studied on bare steel samples by a potentiodynamic polarization technique after 24 h immersion. The morphological properties and corrosion resistance of the coatings were investigated by scanning electron microscope (SEM), optical microscope, electrochemical impedance spectroscopy (EIS) and salt spray tests. 相似文献
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The inhibition efficiencies of zinc chromate, barium metaborate, calcium silicate, amino carboxylate, calcium barium phosphosilicate, aluminum triphosphate and a modified zinc phosphate on the corrosion of steel and zinc were determined by polarization experiments on pigment extracts. Zinc phosphate and zinc chromate were the best and were studied further to determine the effect of pH and chloride concentration on their inhibition of steel. Zinc chromate is adversely affected by high concentration of chloride ions, which effect seems to be less pronounced on zinc. A low pH, although increasing the solubility of zinc phosphate, does not increase its efficiency. The pigments were also incorporated into an epoxy-poly(amide) binder, applied to cold-rolled steel and galvanized steel, exposed at a marine exposure station and the degradation monitored by electrochemical impedance spectroscopy. There was a general correlation between the results of pigment extract studies and atmospheric exposure except in the case of phosphate pigments on cold rolled steel. 相似文献
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The electrochemical potential and current noise generated by multiple electrodes are analyzed by considering the current flowing across each electrode and the electrochemical potential of the electrode array. By introducing the concept of a “virtual electrode”, the analysis of the electrochemical noise generated by an array of electrodes is reduced to the case of two dissimilar electrodes. For each electrode, an apparent impedance, Zρ*, can be determined as the square root of the power spectral density of potential divided by the power spectral density of the individual electrode current. When two dissimilar pairs of nominally identical electrodes are used and it is possible to assume that the pair of electrodes corroding more produces higher noise levels and displays lower impedance, the actual electrode impedance can be obtained with acceptable precision from the value of the nominal impedance. Further, the asymmetry between the two dissimilar pairs can also be quantitatively evaluated. 相似文献
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Ni2+对铝合金磷化膜结构和耐蚀性的影响 总被引:1,自引:0,他引:1
通过表面分析和电化学测试等研究了Ni2+对LY12铝合金表面锌系磷化膜结构和耐蚀性的作用.结果表明,LY12铝合金表面锌系磷化膜的主要成分是Zn3( PO4)2·4H2O,而Ni2+的细化晶粒作用使锌系磷化膜的结构变得更加完整致密,其加入不影响锌系磷化膜的化学组成和相组成;与不含Ni2+的磷化液处理相比,经含有Ni2+的磷化液处理后的铝合金在3.5%的NaCl溶液中的腐蚀电流密度明显下降,在100 mHz频率下的阻抗值明显增大,表现出良好的防护性. 相似文献
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Undesirable anti-corrosion performance of zinc phosphate pigment, the classical chromate replacement, has led researchers to take modification into account. Polyphosphate-based anti-corrosion pigments as a result of modification of zinc orthophosphate have been found to function much more efficiently. This study aimed to evaluate performance of steel samples immersed in 3.5% NaCl aqueous solution-containing zinc aluminum polyphosphate (ZAPP) pigment extract compared to those involving conventional zinc phosphate (ZP) pigment extract and also no pigment (blank) using electrochemical tests such as electrochemical impedance spectroscopy (EIS) and linear polarization (LP) as well as surface analysis. Impedance spectra and polarization curves revealed two different trends, showing the superiority of ZAPP pigment. Based on the results of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), presence of a precipitated layer on the surface was confirmed when steel sample was immersed into the solution-containing ZAPP. 相似文献
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The work deals with the effect of sodium phosphate on the corrosion at the cut edge of electrogalvanized steel, studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and the scanning vibrating electrode technique (SVET). Mapping of the ionic currents revealed that in non-inhibiting solution, the cathode shifts away from the anode as zinc corrosion products precipitate along concentric whitish lines that result from the location of the peak cathodic current. Sodium phosphate inhibits corrosion at the cut edge by precipitation of gel-like zinc phosphate clusters with barrier properties. Breakdown and repassivation of this layer can occur under certain conditions. 相似文献
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A commercial zinc phosphate pigment was incorporated into polypyrrole (PPy) matrix during its electrochemical synthesis in order to improve the corrosion protection of polypyrrole on AISI 1010 steel. PPy/zinc phosphate composite films were synthesised in sodium salicylate medium with high current efficiency and containing 10% by weight of zinc and 4% by weight of phosphate. The influence of stirring and concentration of the electrolyte on the degree of pigment incorporation were investigated, as well as polymerisation time and applied current density. The morphology of the films was determined by scanning electron microscopy (SEM) and the distribution of pigment in the polymeric matrix was carried out by X-ray photoelectron spectroscopy (XPS). The PPy and PPy/zinc phosphate films were submitted to salt spray corrosion test, weight loss test and to electrochemical measurements like corrosion potential with time. In all tests, the composite films showed an enhancement in its protective action in comparison with PPy films. 相似文献
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C. Kavitha T. S. N. Sankara Narayanan K. Ravichandran Il Song Park Min Ho Lee 《Journal of Coatings Technology and Research》2014,11(3):431-442
The present work aims at the development of an energy-efficient and eco-friendly approach for the deposition of zinc phosphate coatings on steel. The study describes the possibility of preparing zinc–zinc phosphate composite coatings by cathodic electrochemical treatment using dilute phosphoric acid as an electrolyte and zinc as an anode. The methodology enables the preparation of coatings with different proportions of zinc and zinc phosphate by suitably varying the applied current density, pH, and treatment time. Adhesion of the coating on mild steel and adhesion of paint film on the phosphate coating were found to be good. The surface morphology of the coatings exhibited platelet-type features and small white crystals (agglomerated at some places) which represented zinc and zinc phosphate, respectively. An increase in current density (from 20 to 50 mA/cm2) increased the size of the zinc crystals, and coatings prepared at 40 and 50 mA/cm2 resembled that of electrodeposited zinc. Since the proportions of zinc and zinc phosphate could be varied with applied current density, pH, and treatment time, it would be possible to use this methodology to prepare coatings that would offer different degrees of corrosion protection. 相似文献
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Cathodic disbondment of epoxy coating with zinc aluminum polyphosphate as a modified zinc phosphate anticorrosion pigment 总被引:1,自引:0,他引:1
As an approach to improve the resistance of protective coatings to the disbondment, modification of the formulation through incorporation of zinc aluminum polyphosphate anticorrosion pigment representing third generation phosphates was examined in this paper. The data obtained from cathodic disbonding test, electrochemical impedance spectroscopy and pull-off indicated that introduction of zinc aluminum polyphosphate within epoxy coating could provide improved resistance to cathodic disbonding as well as superior adhesion strength. The superiority in the presence of the modified pigment was connected to deposition of a layer at the disbonding front and locally controlled pH as well. The precipitation restricting active zone available for electrochemical reaction was confirmed by SEM. 相似文献
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G. Blustein M. C. Dey�� R. Romagnoli A. R. Di Sarli B. del Amo 《Journal of Coatings Technology and Research》2011,8(2):171-181
The purpose of this investigation was focused on reducing the content of zinc phosphate in anticorrosive paints by means of
the incorporation of low quantities of selected soluble corrosion inhibitors. The article describes the anticorrosive behavior
of alkyd paints containing reduced levels of zinc phosphate, zinc oxide, and some soluble compounds used as additives (e.g.,
sodium polyphosphate, sodium phosphate, and sodium benzoate). Anticorrosive solventborne alkyd paints were formulated with
a zinc phosphate content of 10% by volume (v/v) with respect to the total pigment concentration. In all cases, the PVC/CPVC
(pigment volume concentration/critical pigment volume concentration) ratio was 0.8. Experimental paints, applied on sandblasted
SAE 1010 panels, were evaluated by accelerated tests (salt spray cabinet) and electrochemical measurements (electrochemical
impedance spectroscopy, EIS). The results show that the additions of small amounts of soluble corrosion inhibitors to low
content zinc phosphate paint formulations enhance their performance in a very remarkable way. Perhaps, the most outstanding
feature is that the employment of soluble additives allowed the reduction of the zinc phosphate content with concomitant savings. 相似文献
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