Electrochemical impedance spectroscopy study of CuO and Cu coating systems

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.

2018 ◽  
Vol 18 ◽  
pp. 19-26
Author(s):  
Nadjette Belhamra ◽  
Abd Raouf Boulebtina ◽  
Khadidja Belassadi ◽  
Abdelouahed Chala ◽  
Malika Diafi

The purpose of this paper was to investigate the effect of Al2O3 and TiO2 nanoparticles contents on structural proporties, microhardness and corrosion resistance of Zn-Ni alloy coationg. Zn-Ni, Zn-Ni-Al2O3 and Zn-Ni-TiO2 composite coatings were electrodeposited on steel substrate by direct current in sulphate bath.The structure of the coatings was studied by X-ray diffration and by scaning electron miroscopy. The results showed the appearance of Ni5Zn21 phases and that the incrorporation of Al2O3 and TiO2 in the Zn-Ni coating refined the crystal grain size.The corrosion performance of coating in the 0.6M NaCl as a corrisive solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy EIS methods. It was found that the incorporation of nanoparticules in Zn-Ni alloy coating have better corrosion resistance and the values of Rct and Zw increase, while the values of Cdl decrease with increasing of nanoparticules.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
J. Porcayo-Calderon ◽  
R. A. Rodríguez-Díaz ◽  
E. Porcayo-Palafox ◽  
L. Martinez-Gomez

The performance of different Cu-based coins in artificial sweat was evaluated. The electrochemical behavior of the coins was determined by potentiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy. Regardless of the chemical composition of the Cu-based coins, they showed similar polarization curves; particularly, the observed similarity in the anodic zone suggests that the corrosion mechanism is the same in all cases. The presence of Ni and Zn does not appreciably affect the corrosion resistance of Cu. However, the presence of both elements affects the corrosion resistance of Cu. Electrochemical impedance spectroscopy measurements showed the presence of three time constants with very similar characteristics, again indicating that the main corrosion mechanism is the same in all cases. Equivalent circuits confirmed that the corrosion performance of the Ni-Zn-Cu coins depends on the Zn/Ni ratio, such that decreasing this value decreases the corrosion resistance of the alloy. In general, nickel has a detrimental effect due to the formation of highly soluble Ni-based corrosion products.


2017 ◽  
Vol 64 (4) ◽  
pp. 365-370 ◽  
Author(s):  
Sebahattin Kirtay

Purpose The purpose of this paper is to investigate the corrosion resistance of SiO2-Al2O3 coating on mild steel. Design/methodology/approach SiO2-Al2O3 was coated using sol-gel method, and electrochemical measurements were applied to assess the performance of the coated steel. Findings The main conclusion is that SiO2-Al2O3-coated specimens acquired a higher corrosion resistance than that of uncoated specimen. icorr values of the coated specimens were between 12 and 14 times smaller than those of uncoated specimen. The coated specimens exhibited a higher Rcor value at electrochemical impedance spectroscopy analysis. The high values of Rcor and low values of CPEdl observed within the SiO2-Al2O3-coated samples imply an improved anti-corrosion capability. Originality/value In this work, there are three points of originality. First, steel specimens were coated with ormosil-based solution by applying sol-gel dip coating method. Second, both SiO2 and Al2O3 coatings were applied simultaneously at a considerably low temperature, i.e. 200 °C. Finally, the performance of the coated materials against wet corrosion was improved significantly.


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.


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.


2014 ◽  
Vol 789 ◽  
pp. 495-500
Author(s):  
Bing Ying Wang ◽  
Qing Hao Shi ◽  
Wen Long Zhang

The polyurea was modified by adding different amounts of nanometer ZnO. The corrosion behavior of polyurea/primer composite coating system in wet-dry cyclic environment of 3.5% NaCl solution was studied by using the Electrochemical Impedance Spectroscopy (EIS) measurement and adhesion test technology. The experimental result showed that, different mass fractions of nanometer ZnO had different influences on the corrosion resistance property of coating. When the mass fraction of nanometer ZnO was 5%, the composite coating had the largest protective action. The corrosion resistance property of nanometer ZnO can be improved by increasing the density of polyurea coating, however, the corrosion resistance property of polyurea coating will be weakened in case of exceeding the critical adding amount.


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