Journal of Molecular and Engineering Materials

Undoped and Mn-doped TiO₂ thin films have been prepared by sol–gel dip-coating technique on glass and silicon substrates. X-ray diffraction studies showed that both TiO₂ and Mn-doped TiO₂ thin films are of anatase phase with (101) as preferential orientation. All films exhibit high transparency ($\sim$80%) over the visible range. The optical bandgap decreases from 3.66eV to 3.52eV due to the extent of electronic states introduced by doping. Infrared transmission spectra showed Ti–O (625cm${}^{-1}$) and Ti–O–Ti (495–436cm${}^{-1}$) bands. Thermal analysis revealed endothermic reactions between 94^∘C and 110^∘C and exothermic reactions between 406^∘C and 443^∘C. The Nyquist plots depicted that equivalent circuit of the films is an $R_{\mathrm{\text{P}}}{C}_{\mathrm{\text{P}}}$ parallel. The resistance $R_{\mathrm{\text{P}}}$ decreases while the capacitance $C_{\mathrm{\text{P}}}$ increases with Mn-doping.

In this study, coal ash/recycled plastic composite material was fabricated with post-consumer high-density polyethylene (HDPE) and coal ash particles. The main idea of using coal ash, since it is also a waste product, as reinforcing filler in recycled HDPE is to reduce the cost, develop lightweight and produce environmental-friendly materials. Coal ash/recycled plastic composite have been used in significant applications as construction materials including flooring, landscaping, fencing, railing window framing and roof tiles. Effect of coal ash loading on the mechanical properties and thermal conductivity of coal ash/recycled HDPE composite were determined. It is expected to use waste materials in new field by getting novel composite materials with developed mechanical properties. It was found that coal ash filler indicated significant improvement on the mechanical properties of composites. The results show that the impact decreased tremendously from 57.32 to 15.8kJ/m² with only 30wt.% loading of coal ash. The filler increases the elasticity of the material and reduces its ability to absorb deformation energy.

The present work deals with the synthesis of chemically deposited nickel–phosphorous (Ni–P) coating on copper substrate. The process parameters are optimized for maximum hardness based on L${}_{27}$ Taguchi orthogonal design with three process parameters, viz., bath temperature, concentration of nickel Sulphate (a nickel source) and concentration of sodium hypophosphite (a reducing agent), respectively. This is considered and fitted into an L${}_{27}$ orthogonal array (OA) to find out the optimized condition for improved hardness of the coating. The optimized results were obtained from 35g/L of Nickel Sulphate, 20g/L of Sodium Hypophosphite and 90^∘C of temperature. Analysis of variance (ANOVA) was performed to determine the significance of the individual process parameters. ANOVA showed that the factor Nickel Sulphate, the interaction between Sodium Hypophosphite and Temperature were significant in determining the hardness of the coating deposited in the optimized condition. The surface morphology, compositional and phase structure analysis of optimized sample are conducted with the help of scanning electron microscope (SEM), energy-dispersive X-ray analysis and X-ray diffraction (XRD) analyzer, respectively.

The corrosion inhibition of carbon steel (CS) in 3 M HCl was thoroughly investigated in the presence and absence of areca plant extracts as a green corrosion inhibitor. The effect of solution temperature and different amounts of areca plant extracts was examined through gasometric, colorimeter and atomic absorption spectroscopy techniques. Surface studies were screened by scanning electron microscopy (SEM) technique. The results of these techniques show that areca plant extracts (arecanut husk extract, arecanut seed extract and areca flower extract) behave as a nontoxic corrosion inhibitor for CS in 3 M HCl solution. Areca plant extract (arecanut husk extract, arecanut seed extract and areca flower extracts) shows maximum protection efficiency at 4 g/L extract amount.