Studies on anticorrosion properties of polyaniline-TiO2 blended with acrylic-silicone coating using electrochemical impedance spectroscopy

2016 ◽  
Vol 45 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Siti Khumaira Mohd Jamari ◽  
Ramesh Kasi ◽  
Leeana Ismail ◽  
Nur Amirah Mat Nor ◽  
Ramis Rau Subramanian ◽  
...  

Purpose – The purpose of this paper is to study the performance of coatings for corrosion protection. In this research, different compositions of polyaniline (PANI) were added in a pigmented acrylic polyol-silicone coating. The important performance property is corrosion protection. The coatings must be evaluated under corrosive environment. Electrochemical impedance spectroscopy (EIS) is the suitable method to investigate the effect of the addition of PANI in the binder mixture. Design/methodology/approach – The coating resistance, coating capacitance, water uptake and the diffusion coefficient of the coatings were tested for each of the sample. These parameters of the coatings were tested for a period of 60 days of exposure of 3.5 weight per cent solution of sodium chloride salt. EIS results will be further verified by immersion test and salt spray test. Findings – Coating materials developed using 8 and 10 weight per cent of PANI exhibited better coating properties with higher coating resistance for a period 60 days immersion in corrosive environment compared to coatings with lower amount of PANI (2-6 weight per cent). The best coating system obtained the coating resistance value in the range of giga ohms even after the 60th day of exposure. The lowest capacitance value suggested that the coatings have not allowed the electrolyte to permeate to the interface. Water uptake values were found to be in the range of 5 per cent. Salt spray test results showed that the corrosion has initiated at the edges of the scratches only. Practical implications – The study of the effect of conducting polymers in acrylic polyol/silicone resin hybrid binder will be useful for more exploration in coating science. Originality/value – The development of protective hybrid coatings using conducting polymer and TiO2 particles is new. The results show high coating resistance values.

2014 ◽  
Vol 43 (6) ◽  
pp. 371-378 ◽  
Author(s):  
N.A. Mat Nor ◽  
L. Ismail ◽  
S.K.M. Jamari ◽  
K. Ramesh ◽  
B. Vengadaesvaran ◽  
...  

Purpose This paper aims to analyse the coating behaviour in corrosion environment as well as to evaluate the best percentage amount of copper oxide and copper needed for organic coating in order to prevent the corrosion degradation. Electrochemical impedance spectroscopy (EIS) studies have been conducted in order to evaluate the corrosion performance of polyester-epoxy-copper oxide and polyester-epoxy-copper coating systems. Design/methodology/approach The availability of this modem instruments is used to obtain impedance data as well as computer programs to interpret the results that made the technique popular. In addition, EIS is well suited to the study of polymer-coated metals. Findings The results showed that samples containing 25 weight per cent of copper oxide and copper (90P25CuO and 90P25Cu) obtained the excellent corrosion properties from the first day up to 30 days of NaCl immersion. The highest corrosion resistance values obtained by 90P25CuO and 90P25Cu on the 30th day were 7.107 × 108 O and 5.701 × 108 O, respectively, with lower double layer capacitance of 1.407 × 10−9 Farad and 3.935 × 10−9 Farad, respectively. Moreover, the water uptake gained by these two coating samples was the lowest at the end of immersion, which was 0.0084 for 90P25CuO and 0.1592 for 90P25Cu, showing that the sample has good corrosion performance. Originality/value This paper discussed on the highest corrosion resistance, double layer capacitance and the water uptake of the copper (Cu) and copper oxide (CuO) coating system obtained from the EIS measurements.


2015 ◽  
Vol 44 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Siti Khumaira Mohd Jamari ◽  
Ramesh Kasi ◽  
Leeana Ismail ◽  
Nur Amirah Mat Nor ◽  
S. Rames Rau ◽  
...  

Purpose – The purpose of this paper is to develop different combinations of acrylic polyol and silicone resins with various weight ratios and to test the coating properties using electrochemical impedance spectroscopy (EIS). Design/methodology/approach – The performance properties such as coating resistance, capacitance, dielectric constant, water uptake and diffusion coefficient were evaluated using EIS with exposure to 3.5 per cent NaCl solution for 60 days. Findings – The binders developed in this study were coated on cold rolled steel plates. The dry film thickness was found to be in the range of 50 microns. From EIS results, it was found that Acrylic polyol sample with 30 weight per cent of silicone exhibits the best properties, as it has high coating resistance in the range of 109 Ohms for the full period of exposure, whereas all other samples showed poor performance with the exposure time. For these samples, the parameters measured such as the coating resistance of the samples decreased while the coating capacitance, percentage of water uptake and diffusion coefficient of the samples increased after being exposed to corrosive solution for 60 days. The coatings developed by 0, 10 and 60 weight per cent silicone showed high coating capacitance on the first day of exposure, and these systems failed early during the exposure. The water uptake percentage and diffusion coefficient of all samples were found to be less than 50 per cent and below 10-11 cm2 s−1, respectively. An optimum cross-linking between the resins is considered as the main contribution for the best performance shown by the sample that consists of 30 weight per cent of silicone in acrylic matrix that provides maximum barrier properties of the coating. Originality/value – Developing coatings using hybrid binders (silicone resin and acrylic polyol resin) is new area of research. This will explore more research in the formulation of novel coatings.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 113
Author(s):  
Jacob Ress ◽  
Ulises Martin ◽  
Juan Bosch ◽  
David M. Bastidas

The protection of mild steel by modified epoxy coating containing colophony microencapsulated corrosion inhibitors was investigated in this study. The corrosion behavior of these epoxy coatings containing colophony microcapsules was studied by electrochemical analysis using cyclic potentiodynamic polarization and electrochemical impedance spectroscopy. The microcapsule coating showed decreased corrosion current densities of 2.75 × 10−8 and 3.21 × 10−8 A/cm2 along with corrosion potential values of 0.349 and 0.392 VSCE for simulated concrete pore solution and deionized water with 3.5 wt.% NaCl, respectively, indicating improved corrosion protection in both alkaline and neutral pH. Electrochemical impedance spectroscopy analysis also showed charge transfer resistance values over one order of magnitude higher than the control sample, corroborating the electrochemical corrosion potential and current density testing results. Overall, the use of colophony microcapsules showed improved corrosion protection in simulated concrete pore solution and DI water solutions containing chloride ions.


2015 ◽  
Vol 227 ◽  
pp. 515-518 ◽  
Author(s):  
Luigi Calabrese ◽  
Lucio Bonaccorsi ◽  
Chiara Borsellino ◽  
Angela Caprì ◽  
Francesca Fabiano ◽  
...  

In this work the assessment of the corrosion performances in saliva solution of NdFeB magnets coated with silane layers was studied for its application in orthodontic brackets. The silane film, deposited by dip coating technique, has been prepared with varying dipping steps, with the purpose to identify the number of layers able to achieve an optimal protective action. Corrosion protection performance, during immersion in Fusayama synthetic saliva solution, was evaluated by means electrochemical impedance spectroscopy (EIS). The silane coatings evidenced good barrier properties resulting in an improvement of the anti-corrosion performances of the magnets. Better results were observed for samples with at least 15 layers of silane, that evidenced still acceptable protective action after three days of immersion in a Fusayama synthetic saliva solution.


2017 ◽  
Vol 24 (6) ◽  
pp. 825-832 ◽  
Author(s):  
Murat Ates

AbstractMethylcarbazole (MCz) and its nanocomposites with Montmorillonite nanoclay and Zn nanoparticles were chemically synthesized on a stainless steel (SS304) electrode. The modified electrode was characterized by optical microscope, scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), Fourier-transform infrared spectroscopy-attenuated transmission reflectance (FTIR-ATR), four-point probe, and electrochemical impedance spectroscopy (EIS) analysis. The synthesized stainless steel/poly(methylcarbazole) (SS/P(MCz)), stainless steel/poly(methylcarbazole)/nanoclay (SS/P(MCz)/nanoclay), and stainless steel/poly(methylcarbazole)/nanoZn (SS/P(MCz)/nanoZn) were studied by potentiodynamic polarization curves. The protective behavior of these coatings in 3.5% NaCl as the corrosion medium was investigated using Tafel polarization curves, as well as electrochemical impedance spectroscopy. The corrosion protection parameters were also supported by EIS and an equivalent circuit model of Rs(Qc(Rc(QpRct))). The corrosion current of the SS/P(MCz)/nanoclay samples was found to be much lower (icorr=0.010 μA×cm-2) than that of SS/P(MCz)/nanoZn (icorr=0.031 μA×cm-2) and pure SS/P(MCz) samples. These results reveal that chemically synthesized SS/P(MCz), SS/P(MCz)/nanoclay, and SS/P(MCz)/nanoZn nanocomposite film coating have high corrosion protection efficiency (PE=99.56%, 99.89%, and 99.67%, respectively). Thus, based on the study findings, we posit that nanoclay and Zn nanoparticles possess favorable barrier properties, which can be employed in order to achieve improvements in chemical corrosion protection through P(MCz) coating.


2020 ◽  
Vol 25 (4) ◽  

The study is examines the assessment of the corrosion-protective properties of zinc-rich coating based on water sodium silicate (ZRC) using the Electrochemical Impedance Spectra (EIS) with AutoLAB PGSTAT204N. The system consists of three electrodes: Ag/AgCl reference electrode in 3 M solution of KCl, auxiliary electrode – Pt (8x8 mm) and working electrodes for determination potential (Ecorr) and impedance measurement, salt spray test method and natural teszzt method at Dam Bay Marine Research Station, Nha Trang, Khanh Hoa, Viet Nam. ZSC can provide good cathodic protection when zinc content is 70% by weight or more. ZSC with a mixing ratio of High Modulus Liquid Sodium Glass / Zinc Powde : 25/75 by weight (working title – TTL-VN) has good corrosion protection after 16 cycles salt spray test and after 18 months natural test in seawater. The paint film has basic parameters as adhesion – 4,41 MPa, flexural strength – 2 mm, pendulum hardness – 0,62 conventional units and initial coating potentia l – 0,96 V Ag/AgCl.


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