Gazala Ruhi; Haritma Chopra;Sundeep K. Dhawan; Pradeep Sambyal; Hema Bhandari
Abstract
In a novel approach, Polypyrrole/Gum Acacia composites (PPy/GA) were synthesized by in-situ oxidative polymerization of pyrrole on the Gum Acacia (GA) surface by using FeCl3 as oxidant. The 1 HNMR and FTIR confirms the presence of peaks of Polyprrole and Gum Acacia in the composite. The microstructural ...
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In a novel approach, Polypyrrole/Gum Acacia composites (PPy/GA) were synthesized by in-situ oxidative polymerization of pyrrole on the Gum Acacia (GA) surface by using FeCl3 as oxidant. The 1 HNMR and FTIR confirms the presence of peaks of Polyprrole and Gum Acacia in the composite. The microstructural analysis of the composite reveals uniform layer of Polypyrrole on the surface of GA particles. The X-ray Diffraction pattern reveals the amorphous nature of the composite. Powder coating technique was used to design the composite coatings. The electrochemical studies like Open Circuit Potential (OCP) variation with time, Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) were conducted in 3.5% NaCl solution to evaluate the corrosion resistance of the coatings. The composite coatings demonstrated superior corrosion resistance in salt spray fog of 5.0% NaCl (under accelerated test conditions in salt spray chamber). The synergistic combination of the corrosion inhibition properties of Gum Acacia and the redox properties of Polypyrrole is the reason for the occurrence of high corrosion resistance of the composite coatings. The present coating composition has shown excellent corrosion resistance and can be a potential coating formulation for mild steel substrate used in various applications under saline conditions.
H. C. Ananda Murthy; Somit Kumar Singh
Abstract
Aluminum matrix composites (AMCs), reinforced with ceramic particulates, have significant applications in the field of aerospace, marine, automobiles, sports and recreation. Al-TiC particulate composite has better potential for high-temperature applications. The corrosion behaviour of Al 6061-TiC particulate ...
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Aluminum matrix composites (AMCs), reinforced with ceramic particulates, have significant applications in the field of aerospace, marine, automobiles, sports and recreation. Al-TiC particulate composite has better potential for high-temperature applications. The corrosion behaviour of Al 6061-TiC particulate composites prepared by stir casting route, has been explored in chloride medium using electroanalytical techniques such as Tafel, Cyclic polarization and Impedance measurements (EIS). SEM and EDX analysis of the microstructures obtained in both matrix alloy and reinforced composites were performed in order to know the effect of titanium carbide on the corrosion resistance of composites. The polarization studies reveal an increase in the corrosion resistance in composites compared to the matrix alloy. The observed increase in corrosion resistance of TiC particulate reinforced composites is attributed to excellent bond integrity of TiC particulates with aluminium and possible electrochemical decoupling between TiC particles and Al 6061 matrix alloy. The EIS study reveals that the polarisation resistance (Rp) increase with increase in TiC content in composites and the corrosion process is mainly charge transfer controlled. Titanium carbide is proved to be a potential reinforcement for improved corrosion resistance in Al MMCs.
N. A. Al-Mobarak
Abstract
The corrosion resistance of titanium alloy, Ti–6Al–7Nb, was investigated through electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) measurements and scanning electron microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. The tests were done in Hank's solution ...
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The corrosion resistance of titanium alloy, Ti–6Al–7Nb, was investigated through electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) measurements and scanning electron microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. The tests were done in Hank's solution at 37 o C for immersion periods expanded to 169 h. A high corrosion resistance was obtained for Ti–6Al–7Nb alloy in hank's solution due to the stable passive film formed on its surface. The EIS results indicated the presence of a single passive layer immediately after immersion. However, after 24 h of immersion in hank's solution, the EIS exhibited the presence of a bi-layered surface corresponding to an inner layer and an outer layer. Further, the film formed on the alloy after 169 h was confirmed by SEM and EDX analysis as calcium and phosphate may be due to apatite formation.