Correlation of exposure at the port of chennai (bay of bengal, India) and salt-spray tests with electrochemical impedance spectroscopy of coating systems

2002 ◽  
Vol 85 (3) ◽  
pp. 229-233 ◽  
Author(s):  
M Selvaraj ◽  
M Natesan ◽  
P Jayakrishnan
Author(s):  
L. M. Flores Tandy ◽  
J. J. Pérez Bueno ◽  
Y. Meas Vong

This chapter shows results related to synthesizing hybrid materials composed of polymer matrix/nano-TiO2, which possesses a photochromic property under UV irradiation. The synthesized TiO2 was amorphous, but, for the hybrid photochromic response, the required illumination is that with the same or superior energy than semiconductor bandgap. Moreover, the photochromism requires OH proportionate to preparing within an alcohol, and by releasing them by temperature, the color change resulted permanent. The hybrid materials were prepared as coatings, which display multifunctional characteristics. The polymeric matrix was proven with different kinds of organic polymers and solvents. This phenomenon was investigated through Salt Spray Test, Electrochemical Impedance Spectroscopy, HRTEM, SEM, Reflectance, Fluorescence, Contact Angle, and EPR. The capacity to act as a barrier for corrosion protection was investigated. Finally, the hybrid material is proposed as an indicator for applications in engineering.


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.


2011 ◽  
Vol 295-297 ◽  
pp. 1124-1128 ◽  
Author(s):  
Qiong Zhou ◽  
Xiao Mei Su ◽  
Hong Zhang ◽  
Yong Ji Weng

Polyaniline (Pani) on graphite electrode was synthesized electrochemically under galvanostatic condition at current density of 2.0 mA/cm2 from aqueous solution of 1.0 mol/L HCl and 0.25 mol/L aniline monomer. The Electrochemical Impedance Spectroscopy investigation of Pani was carried out at different stages of polymers oxidation. In the potential range 0.2V~0.7 V vs SCE, with the increase of test potential the membrane resistance decreased rapidly, and Faraday process at the polymer/solution interface weakened. When the test potential in range of -0.8V~0.2V or 0.7V~0.8V, the film has a higher membrane resistance, and lower ionic charge transfer resistance, which indicated that the ion exchange for the charge compensation at the polymer/electrolyte interface is much easier. And anticorrosion properties of Pani coating of different oxidations was investigated by salt spray test. The final visual observations of the tested coatings are in agree with the results of electrochemical impedance spectroscopy.


Sign in / Sign up

Export Citation Format

Share Document