Electrodeposition Based Preparation of Zn–Ni Alloy and Zn–Ni–WC Nano-Composite Coatings for Corrosion-Resistant Applications

Zinc (Zn) is one of the five most widely consumed metals in the world. Indeed, more than 50% of all the zinc produced is used in zinc-galvanizing processes to protect steel from corrosion. Zn-based coatings have the potential for use as a corrosion-resistant barrier, but their wider use is restricted due to the poor mechanical properties of Zn that are needed to protect steel and other metals from rusting. The addition of other alloying elements such as Ni (Nickle) and WC (Tungsten Carbide) to Zn coating can improve its performance. This study investigates, the corrosion performance of Zn–Ni coating and Zn–Ni–WC composite nanocoatings fabricated on mild steel substrate in an environmentally friendly bath solution. The influence of WC nanoparticles on Zn–Ni deposition was also investigated. The surface morphologies, texture coefficients via XRD (X-ray diffraction), SEM (Scanning Electron Microscopy), and EDS (Energy-dispersive X-ray spectroscopy) were analyzed. The electrochemical test such as polarization curves (PC) and electrochemical impedance spectroscopy (EIS) resulted in a corrosion rate of 0.6948 Å/min for Zn–Ni–WC composite nanocoating, and 1.192 Å/min for Zn–Ni coating. The results showed that the Zn–Ni–WC composite nanocoating reduced the corrosion rate by 41.71% and showed an 8.56% increase in microhardness compared to the hardness of the Zn–Ni coating. These results are augmented to better wettable characteristics of zinc, which developed good interfacial metallurgical adhesion amongst the Ni and WC elements. The results of the novel Zn–Ni–WC nanocomposite coatings achieved a great improvement of mechanical property and corrosion protection to the steel substrate surface.

Comparison of processing parameter effects during magnetron sputtering and electrochemical anodization of TiO2 nanotubes on ITO/glass and glass substrates

Titanium thin films were deposited on glass and indium tin oxide (ITO) coated glass substrates by radio-frequency (RF) magnetron sputtering under varying sputtering parameters as: power, pressure, substrate temperature and target-substrate distance. The crystalline structure, crystallite size and texture coefficients of the films were evaluated in detail. As the evaluation points out, 100 W, 1.33 Pa ambient temperature and 70 mm were determined as the optimum sputtering parameters for intended crystalline structures. Subsequently, electrochemical anodization experiments were performed via varied electrolytes and under various anodization parameters (voltage, time and electrolyte type) in a two-electrode electrochemical cell using the films obtained through the optimized sputtering parameters. The anodized samples were annealed at 450 °C for 1 h in air in order to obtain anatase transformation and the desired crystalline structure. The surface morphologies and the crystalline structures of the anodized films were evaluated through x-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. Finally, the anodization parameters for the formation of TiO2 nanotube arrays were determined as: 35 V and 35 min. in an electrolyte composed of 0.3 wt.-% NH4F – 2 wt.-% water – ethylene glycol.

Preparation and Characterization of Transparent Conducting Mn and Ni-Doped Zinc Oxide Films Prepared by Successive Ionic Layer Adsorption and Reaction Method

This paper reported the preparation and characterization of transparent conducting oxide thin films. Undoped and doped ZnO thin films were prepared by SILAR method. The micro-structural and optical properties were investigated. X-ray diffraction patterns revealed that the prepared thin films are polycrystalline in nature and has a hexagonal structure. The micro-structural properties of prepared thin films were calculated and crystallite size tends to changes due to dopant. The texture coefficients have been evaluated and found to be greater than unity revealing high texturing of the film. Undoped and Mn-doped ZnO prefer the orientation of (002) but Ni-doped ZnO and Mn and Ni co-doped ZnO prefers (100) orientation. The transmittance spectra of pure and transition metal-doped films were plotted against UV-Vis-NIR region and found that the transmittance changes with dopant and nature of doping. The optical band gap values were found to be in the range of 3.00–3.39 eV. The optical constants such as extinction coefficient, refractive index, dielectric constant and optical conductivity were examined.

Synthesis and Characterization of Co0.8-x Nix Zn0.2 Fe2O4 Ferrites by Williamson–Hall and Size–Strain Plot Methods

The Co-Zn ferrite (x=0.00) and Nickel doped Co-Zn ferrites (x=0.24) was synthesized by low cost solid state reaction method and characterized by XRD technique. The X-ray diffraction results for the samples showed the formation of single phase cubic spinel. The lattice constant and particle size for Co-Zn ferrite(x=0.00) is found to be 8.3465 Å and 26.72 nm and for Nickel doped (x=0.24) it is 8.3440 Å and 24.21nm. Micro strain (ε), Dislocation density(ρD), Hopping lengths (LA and LB), Bond lengths (A - O and B-O), Ionic radii (rA and rB), Texture coefficients (Thkl) and Standard deviation (σ) are also reported. The particle size is confirmed by scanning electron microscope (SEM). The Williamson-Hall plot and stress-strain plot also employed to understand the mechanical properties of materials.

Role of Oxygen Pressure on the Surface Properties of Polycrystalline Cu2O Films Deposited By Thermal Evaporator

<p>Polycrystalline cuprous oxide (P-Cu2O) films are deposited on Cu substrates for various (0.2, 0.3 and 0.4 mbar) oxygen pressures (OP) by thermal evaporator. The XRD pattern shows the development of Cu (200), Cu2O (200) and Cu2O (311) diffraction planes which confirms the deposition of P-Cu2O films. The intensity of Cu2O (200) and Cu2O (311) planes is associated with the increase of OP. The crystallite size and microstrains developed in (200) and (311) planes are found to be 19.31, 21.18, 11.32 nm; 22.04, 23.11, 12.08 nm and 0.113, 0.103, 0.193; 0.099, 0.096, 0.181 with increasing OP respectively. The d-spacing and lattice constant are found to be 0.210, 0.128 nm and 0.421, 0.425 nm respectively. The bond length of P-Cu2O film is found to be 0.255 nm. The crystallites/unit area of these planes is found to be 12.21, 7.46, 45.16 nm-2 and 8.21, 5.75, 37.16 nm-2 respectively. The texture coefficients of these planes are found to be 1.22, 1.26, 1.11 and 0.78, 0.74 and 0.56 with increasing OP respectively. The O and Cu contents are found to be 5.31, 5.92, 6.94 wt % and 83.01, 82.44, 80.65 wt % respectively. The thickness and growth rate of P-Cu2O films are found to be 87.9, 71.9, 65.5 nm and 17.6, 14.2, 13.1 (nm/min) with increasing OP respectively. The SEM micro-structures reveal the formations of patches of irregular shapes, rounded nano-particles, clouds of nano-particles and their distribution depend on the increasing OP. The refractive index and energy band gap of P-Cu2O films are found to be 1.96, 1.89, 1.92 and 2.47, 2.44 and 2.25 eV with increasing OP respectively.<br /><br /></p>

Synthesis and structural analysis of Ni0.45Cu0.55Mn2O4 by Williamson–Hall and size–strain plot methods

This paper describes synthesis and structural properties of Ni0.45Cu0.55Mn2O4 nanopowder, obtained by co-precipitation route. XRD pattern reveals cubic structure with lattice parameter 8.305 Å. We report crystallite size (D), micro strain (ε), dislocation density (ρD), and hopping lengths (LA and LB). We also report preferential orientation by texture coefficients [Tc (h k l)]. The Williamson-Hall plot and stress-strain plot also employed to understand the mechanical properties of materials.