Corrosion and Dye

The 1,2,3-Benzotriazol were evaluated in the present work as corrosion inhibitors for protection of the carbon steel in chloride solutions. The corrosion protection performance was investigated by means of weight loss and DC polarization and electrochemical impedance spectroscopy (EIS). Scanning electron microscope was used to study the surface topography during corrosion tests. The results show that all inhibitors under study confer corrosion protection to the carbon steel forming a thin organic layer on the substrate surface. The following quantum chemical indices such as the charge density distribution, highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), energy gap, ?N and dipole moment (u) were considered. The inhibition efficiencies obtained from the employed methods are nearly closed. From the obtained data it was found that, the inhibition efficiency increases with increasing the inhibitor concentration until the optimum one.

The natural plant product used as a medicine namely marigold were tested as corrosion inhibitor of Zn in 0.5M of HCl. The Cyclic-Voltameter, potentiometry technique data suggested that the inhibition efficiency increases with the concentration of extract. The inhibition efficiency of inhibitor interpreted as adsorption on metal surface.

Plant extracts are excessively used as corrosion inhibitors. Plant extracts contain a variety of organic compounds such as alkaloids, flavonoids, tannins, cellulose and polycyclic compounds. The compounds with hetero atoms-N, O, S, P coordinate with (corroding) metal atom or ion consequently forming a protective layer on the metal surface, that prevents corrosion. These serve as cheaper, readily available, renewable and environmentally benign alternatives to costly and hazardous corrosion inhibitors .This study reports screening of phytoconstituents and also reports the influence of the addition of Pongamia pinnata (L.) Pierre leaves extract on the corrosion inhibition of mild steel in 2.0 M H2SO4 solution using the Mylius thermometric technique. Results of the study revealed that Pongamia pinnata (L.) Pierre. leaves act as corrosion inhibitor for mild steel in the acidic medium. The addition of 0.1 M potassium chloride, potassium bromide and potassium iodide to the inhibitor enhanced the inhibition efficiency. The order of reactivity of halide ions is of the order KI > KBr > KCl. The inhibition efficiency increased 58 % to 78 % at a concentration of 0.1 M KI and 5.0 % of inhibitor concentration. The values of adsorption of Pongamia pinnata (L.) Pierre leaves extract onto the mild steel surface show that the process is spontaneous.

Bipolar plates (BPs) are a key component of Proton Exchange Membrane (PEM) Fuel Cells with multifunctional character. They uniformly distribute fuel gas and air, conduct electrical current from cell to cell, remove heat from the active area, and prevent leakage of gases and coolant. Bi-Polar Plates also significantly contributes to the volume, weight and cost of Proton Exchange Membrane Fuel Cell stacks. Hence, there are vigorous efforts worldwide to find suitable materials for Bi-Polar Plates. The materials include non-porous graphite, coated metallic sheets, polymer composites, etc. This paper reviews various types of materials, in use and proposed, for Bi-Polar Plates and critically examines their physical and chemical properties.

Cyperus Articulates extract (CA), was investigated as a green corrosion inhibitor for C steel in 0.5 MH2SO4 solution using mass loss, electrochemical frequency modulation (EFM), potentiodynamic polarization, and (EIS)electrochemical impedance spectroscopy techniques. The temperature effect on corrosion behavior with addition of various concentrations was done in the temperature range of 25-45 ºC by weight loss. Polarization diagram given that the investigated extract is a cathodic behavior. The inhibition efficiency was found to rise with increase in the investigated extract concentration and lower with increase in solution temperature. Adsorption of inhibitor on metal surface found obeyed the adsorption isotherm Langmuir’s. The activation and adsorption parameters were measured and illustrated. The data from electrochemical and chemical methods are a good agreement.

The effect of Psidium guajava leaf as corrosion inhibitors in 10 % sulfamic acid solution was conducted using different techniques at temperatures 298 K.The effect of temperature was studied and activation and adsorption thermodynamic parameters were computed and discussed. The surface morphology was analyzed using scanning electron microscope (SEM). Potentiodynamic polarization studies showed that Psidium guajava leaf acts as mixed type inhibitor for corrosion of C-steel in 10% NH2SO3H solution. The addition of Psidium guajava leaf led to increase in the charge transfer resistance (Rct) and decrease in capacitance of the double layer (Cdl). The inhibition mechanism involve physisorption. The adsorption of this extract on C-steel surface obeys isotherm. All studied techniques gave similar results. Surface of C-steel was analyzed using scanning electron microscopy (SEM) technique.

Effect of Black tea extract (BTE) as green inhibitor on the corrosion behavior of mild steel in 1.0M HCl, 1.0M H2SO4 and 35g/l NaCl was studied by potentiodynamic polarization techniques open–circuit potential, linear polarization resistance and Tafel plots polarization, its clear BTE gives inhibition in both anodic and cathodic slopes in Tafel polarization, that indicate this inhibitor used as mixed-type inhibitor, the thermodynamic adsorption isotherm was studied and falls into Langmiur isotherm, and it is physisorption isotherm. Also the surface morphology of MS samples without and with the inhibitor was examined using scanning electron microscopy.

This research has focused on developing eco-friendly treatments for modifying the fabric surface. In the present study, the cotton fabric was treated with chitosan at different concentrations to find a suitable concentration on the dyeability with a natural dye from the flowers of Lantana camara. The influence of dyeing methods with mordants, i.e. pre-mordanting, post-mordanting and simultaneous mordanting was determined. The light, wash and rub fastness of chitosan treated samples were measured and compared with untreated samples. Chitosan-treated cotton fabrics improved both in dyeability and fastness compared with untreated cotton fabric. The cotton fabrics treated with chitosan not only provided better depth of shade but also provided better wash fastness and light fastness than those of the untreated fabrics. The use of different mordants and mordanting methods affected the dye shade and depth of shade differently on the dyed fabrics both with and without chitosan. The range of colour developed on the dyed materials was evaluated and the dye absorption on the cotton was studied by using K/S values.

The adsorption and inhibition efficiency effect of antipyrine derivatives on the c-steel alloy in 1M HCl were investigated using electrochemical techniques (potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM)). The inhibition efficiency of the inhibitors increased with increasing the concentration of the derivatives and increased also with increasing the temperature. Polarization curves revealed that these compounds are chemical type inhibitors. The adsorption of these compounds follows Langmuir adsorption isotherm. Some thermodynamic parameters of activation and adsorption processes were also determined and discussed.