97 research outputs found
Extract of Combretum micranthum as corrosion inhibitor for Al – Si – Mg alloy in simulated sea water environment
The leaf extract of Combretum micranthum (CM) was tested as green corrosion inhibitor for Al-Si-Mg alloy in 3.5wt% NaCl solution using gravimetric and linear polarization methods at 300C, 500C and 700C, from 1, 2, 3, 4, 5 hours of exposure time with concentration of the extract 0, 0.2, 0.4, 0.6, 0.8 and 1.0 v/v respectively. The result obtained indicate that the leaf extract of CM is a good corrosion inhibitor in the simulated sea water medium. The inhibition efficiency of the extract increased with an increase in concentration of the CM extract and decreased with increase in temperature. On the other hand, inhibition efficiency (IE%) synergistically decreased on addition of surfactant (Monoethylamine). The adsorption of the inhibitor on Al-Si-Mg surface is exothermic, Spontaneous and is best described by Langmuir, Freundlick and El-Awady adsorption models. The calculated values of activation energy, enthalpy of activation entropy of activation, free energy of process is by physical adsorption. Equally, methanol extract CM is a good adsorption inhibitor for the corrosion of Al-Si-Mg in 3.5wt% NaCl solution. Tafel polarization analysis indicates that the studied plant extract is a mixed type inhibitor. http://dx.doi.org/10.4314/njt.v35i4.2
Corrosion Resistance of AA6063-Type Al-Mg-Si Alloy by Silicon Carbide in Sodium Chloride Solution for Marine Application
The present work focused on corrosion inhibition of
AA6063 type Al-Mg-Si alloy in sodium chloride (NaCl) solution
with a silicon carbide inhibitor, using the potentiodynamic
electrochemical method. The aluminium alloy surface morphology
was examined, in the as-received and as-corroded in the
un-inhibited state, with scanning electron microscopy equipped
with energy dispersive spectroscopy (SEM-EDS). The results
obtained via linear polarization indicated a high corrosion potential
for the unprotected as-received alloy. Equally, inhibition efficiency
as high as 98.82% at 10.0 g/v silicon carbide addition was obtained
with increased polarization resistance (Rp), while the current
density reduced significantly for inhibited samples compared to the
un-inhibited aluminium alloy. The adsorption mechanism of the
inhibitor aluminium alloy follows the Langmuir adsorption
isotherm. This shows that the corrosion rate of aluminium alloy
with silicon carbide in NaCl environment decreased significantly
with addition of the inhibito
Corrosion Protection Effect of Chitosan on the Performance Characteristics of A6063 Alloy
This article outlines the behaviour of water-soluble chitosan as an effective inhibitor on aluminium alloy in 3.65% NaCl at room temperature. The inhibitive ability of water-soluble chitosan was examined using electrochemical potentiodynamic polarization techniques, mass loss measurements and computational studies. The outcome of the experiment reveals that chitosan inhibited aluminium alloy in sodium chloride solution exhibits better corrosion protection than the uninhibited because chitosan nanoparticles minimize the ingression of chloride ion into the active sites of aluminium alloy by forming thin film on its surface. The losses in mass by the inhibited aluminium alloy were found to reduce as the concentration of chitosan increases. Results obtained showed that chitosan could offer inhibition efficiency above 70%. Polarization curve demonstrated that chitosan in 3.65% NaCl at room temperature acted as a mixed-type inhibitor. Adsorption of chitosan nanoparticles on the aluminium alloy was found to follow Langmuir adsorption isotherm with correlation regression coefficient (R2
) value of 0.9961
Treated Rhizophora mucronata tannin as a corrosion inhibitor in chloride solution
Treated Rhizopora mucronata tannin (RMT) as a corrosion inhibitor for carbon steel and copper in oil and gas facilities was investigated. Corrosion rate of carbon-steel and copper in 3wt% NaCl solution by RMT was studied using chemical (weight loss method) and spectroscopic (FTIR) techniques at various temperatures in the ranges of 26–90C. The weight loss data was compared to the electrochemical by the application of Faraday’s law for the conversion of corrosion rate data from one system to another. The inhibitive efficiency of RMT was compared with commercial inhibitor sodium benzotriazole (BTA-S). The best concentration of RMT was 20% (w/v), increase in concentration of RMT decreased the corrosion rate and increased the inhibitive efficiency. Increase in temperature increased the corrosion rate and decreased the inhibitive efficiency but, the rate of corrosion was mild with RMT. The FTIR result shows the presence of hydroxyl group, aromatic group, esters and the substituted benzene group indicating the purity of the tannin. The trend of RMT was similar to that of BTA-S, but its inhibitive efficiency for carbon-steel was poor (6%) compared to RMT (59%). BTA-S was efficient for copper (76%) compared to RMT (74%) at 40% (w/v) and 20% (w/v) concentration respectively. RMT was efficient even at low concentration therefore, the use of RMT as a cost effective and environmentally friendly corrosion inhibiting agent for carbon steel and copper is herein proposed
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