B. M. Praveen

Corrosion Behavior of Zn‐TiO2 Composite Coating

Zn‐TiO2 composite coatings were electrodeposited on mild steel using an electrolyte containing dispersed nanosized TiO2. The corrosion resistance of the coating was studied in (3.5 wt.%) NaCl solution by electrochemical and weight loss measurements. The study revealed higher resistance of composite coating to corrosion. The composite coatings were porous free and the service life of coatings was examined by salt spray test. The surface morphology was investigated by recording the scanning electron microscopy (SEM) images of coating before and after corrosion. SEM studies inferred the reduction in crystalline size of composite coating and it showed the improved corrosion resistance property. The anti‐corrosion mechanism of the composite coating was also discussed.

Microstructural and Mechanical Studies of PVA Doped with ZnO and WO3 Composites Films

Polymer composites of ZnO and WO3 nanoparticles doped polyvinyl alcohol (PVA) matrix have been prepared using solvent casting method. The microstructural properties of prepared films were studied using FTIR, XRD, SEM, and EDAX techniques. In the doped PVA, many irregular shifts in the FTIR spectra have been observed and these shifts in bands can be understood on the basis of intra/intermolecular hydrogen bonding with the adjacent OH group of PVA. The chemical composition, phase homogeneity, and morphology of the polymer composites of the polymer film were studied using EDAX and SEM. These data indicate that the distribution of nanosized ZnO and WO3 dopants is uniform and confirm the presence of ZnO and WO3 in the film. The crystal structure and crystallinity of polymer composites were studied by XRD. It was found that the change in structural repositioning and crystallinity of the composites takes place due to the interaction of dopants and also due to complex formation. The mechanical studies of doped polymer films were carried out using universal testing machine (UTM) at room temperature, indicating that the addition of the ZnO and WO3 with weight percentage concentration equal to 14% increases the tensile strength and Young’s modulus.

Advancement in Microstructural, Optical, and Mechanical Properties of PVA (Mowiol 10-98) Doped by ZnO Nanoparticles

The current paper explores the preparation of PVA nanocomposites by doping with zinc oxide (ZnO) nanoparticles using the method of coagulation and solvent casting technique. The dopant zinc oxide nanoparticle is prepared by simple precipitation method and is confirmed by the X-ray diffraction (XRD) studies. The XRD studies explore that the average particle size of the synthesized nanoparticles is 55 nm and show that the crystallinity factor of PVA nanocomposites is influenced by the interaction occurring between the PVA main chain and the ZnO nanoparticle. The FTIR spectroscopy suggests that the formulation of complexes occurring between the dopants and the PVA main chain is due to inter or intra molecular hydrogen bonding. UV-vis spectra explore the dramatic decrease in the optical energy gap of nanoparticles doped polymer composites and the variations of Urbach energy () related to crystallinity for various dopant concentrations. The mechanical properties of the PVA nanocomposites were explored using universal testing machine (UTM) that reflects that, for % doping concentration, there is an increase in the tensile strength, stiffness, and Young’s modulus, whereas, for % concentration, the percentage total elongation at fracture is found to be the maximum. The morphological behavior and homogenous nanoparticle distribution in the composites were examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX).

Pulse Electrodeposition, Characterization, and Corrosion Behavior of Ni-Si3N4 Composites

The Ni-Si3N4 composites were generated by pulse electrodeposition method (PC). Operating variables were optimized for getting a good deposit. The quantity of Si3N4 particles in the coating was analyzed by an energy-dispersive x-ray diffraction spectrometer. X-ray diffraction and scanning electron microscopy were used to analyze the structure and surface morphology of the coatings. Texture coefficient and hardness of the deposits were determined and discussed. The corrosion behavior of the coatings was analyzed by traditional weight loss and electrochemical methods. Comparisons of the corrosion behavior of coatings obtained by direct current electrodeposition and with pulse electrodeposition were investigated.

Generation of Ni–Si3N4 nanocomposites by DC, PC and PRC electrodeposition methods

Ni–Si3N4 nanocomposite thin films were fabricated by direct current (DC), Pulse current (PC) and Pulse reverse current (PRC) electrodeposition methods. The structure and surface morphology of thin films were analysed by XRD, Scanning Electron Microscopy and Atomic Force Microscope. Corrosion protection performance of the Ni–Si3N4 nanocomposite on mild steel in 3.5% NaCl corrosive medium was assessed by electrochemical method. Texture coefficient and microhardness of the thin films were determined and discussed. Comparisons and performance of corrosion resistance of these coatings obtained by DC electrodeposition, PC electrodeposition and with PRC electrodeposition were investigated.

Dielectric and electric conductivity studies of PVA (Mowiol 10-98) doped with MWCNTs and WO3 nanocomposites films

In this article, we report the doping of MWCNTs and WO3 nanoparticles into the PVA matrix for fabricating a novel class of PVA nanocomposite using solvent casting method. The behavioral effect of these embedded nanoparticles in PVA matrix for different doping concentrations on microstructural, dielectric and electric properties are analyzed for possible device applications. The formation of nanocomposites and their microstructural variations for different doping concentration were inspected by x-ray diffraction studies. As the doping concentration increases from x = 0 to 7.5 wt%, the DC conductivity rises from 1.0528 × 10−11 to 3.7764 × 10−9 S cm−1 and beyond the dopant concentration x > 7.5 wt% the DC conductivity was found to decrease. The frequency dependent dielectric constant decreases with an increase in dopant concentration. The values of electric modulus, AC conductivity and polarization relaxation time extracted from dielectric data spectacles an enhancement behavior in conducting property of PVA nanocomposites with increasing concentration up to x = 7.5 wt% and above x > 7.5 wt% the values found decreasing. The information regarding the surface morphology and chemical configuration of the nanocomposites are determined by using atomic force microscope (AFM), scanning electron microscope (SEM) and energy dispersive analysis of x-rays (EDS) techniques.

Acid Corrosion Inhibition of Steel by Lamotrigine

Corrosion inhibition effect of lamotrigine on steel in 1.0 M HCl and 0.5 M H2SO4 was studied by techniques like weight loss, polarisation, and electrochemical impedance spectroscopy. Results indicated that lamotrigine is more competent in HCl than in H2SO4 and is justified by scanning electron micrographs. Protection efficiency increased with the concentration of inhibitor and decreased with temperature. Adsorption study revealed the comprehensive adsorption of lamotrigine molecules on steel surface.

Electrochemical study on inhibitory effect of Aspirin on mild steel in 1 M hydrochloric acid

Abstract Aspirin was investigated as a good corrosion inhibitor for mild steel in 1 M hydrochloric acid at a temperature region from 303 to 333 K. The computed inhibition efficiency increases by increasing the inhibitor concentration and decreases by increasing the temperature. The investigation was done by weight loss, electrochemical measurements such as Tafel polarization and electrochemical impedance spectroscopy. Inhibition effect is attributed to the adsorption of inhibitor on the surface of the mild steel. The Tafel method reveals that the Aspirin acts as a mixed type inhibitor. Activation parameters suggest that the adsorption process is exothermic in nature. SEM photographs of mild steel in the absence and presence of inhibitor visualize the adsorption layer on the surface of the mild steel.

Experimental and theoretical studies of hydralazine hydrochloride as corrosion inhibitor for mild steel in HCl acid medium

Purpose – The purpose of this paper is to investigate the inhibition effect of hydralazine hydrochloride as a corrosion inhibitor for mild steel in 1M HCl. The inhibition effect was studied at different temperatures, ranging from 303 to 333°K. Design/methodology/approach – The inhibition efficiency of hydralazine hydrochloride was analyzed using weight loss, Tafel polarization, electrochemical impedance spectroscopy and surface morphology methods. The effect of temperature on the corrosion behavior of mild steel in 1M HCl was studied and discussed using an adsorption isotherm and activation parameters. Findings – Weight loss, polarization and impedance showed that the inhibition efficiency increases with an increase in the concentration of hydralazine hydrochloride for mild steel in 1M HCl. The inhibitive action may be attributed to the adsorption of the inhibitor molecule on the active sites of the metal surface by the Langmuir adsorption isotherm. Polarization curves indicated that hydralazine hydrochlo...

Benzimidazole derivatives as corrosion inhibitors for zinc in acid solution

The corrosion inhibition characteristics of 2-mercapto benzimidazole (MBI), 2-mercapto benzimidazolyl-ethyl acetate (MBEA), 2-hydroxy benzimidazole (HBI) and 2-hydroxy 5-nitro benzimidazole (HNBI) on zinc corrosion in 0.1 M hydrochloric acid were investigated by weight loss and potentiodynamic polarization techniques. The inhibition efficiency increased with increase in inhibitor concentration but decreased with increase in temperature. The adsorption of MBI and MBEA obeyed Langmuir’s adsorption isotherm but HBI and HNBI followed Temkin’s adsorption isotherm. Thethermodynamic functions for adsorption processes were evaluated. The existence of film on metal surface in presence of inhibitors was established by scanning electron microscopy (SEM) images.