Narrow Results

This study is conducted to examine the tribological performance of WC-12Co coating and WC-12Co mixed with yttrium oxide coating applied on mild steel. Mild steel machinery is usually used for hydropower generation but the sediments present along with the river water cause wear on the machinery surface. DUCOM slurry pot tester setup was used for the experiments. This study was based on the coatings of WC-12Co as well as the mixing of yttrium oxide with WC-12Co powder in various proportions ranging from 1–3% by weight on mild steel. The high-velocity oxygen fuel thermal spray coating process was used to deposit a microlayer coating on the mild steel. It is observed that the microhardness of the coatings increases with the addition of yttrium oxide. The experiments were carried out varying the concentration, rotational speed, and test duration in the range of 10–40% by weight, 750–1500rev/min, and 30–120min duration, respectively. It is observed that the WC-12Co+2%Y₂O₃ coating has a higher erosion resistance.

Using the conditions obtained from various simple and complex models, the energy of the surface area was calculated with the help of electronic structural transitions and thermo-sublimation approximations occurring in yttrium oxide nanoparticles irradiated with different energy deuterium ions. The depth of penetration of deuterium ions of different energies into the yttrium oxide sample, the rate of energy loss, and the energy of the surface area under the influence of temperature sublimation were determined using basic methods. In addition, the screening radius and erosion rate were determined using the Sigmund and Thomas–Fermi shielding function.

In this study, ${\mathrm{\text{Eu}}}^{3+}$-doped yttrium oxide nanophosphors were prepared using the hydrothermal method assisting with the polyacrylic acid (PAA), phenol formaldehyde resin precursor (PF), and gum arabic (GA), respectively and their structural and optical properties were studied. X-ray diffraction (XRD) patterns of the samples can be well indexed to the cubic structure. Additionally, scanning electron microscopy (SEM) images showed that the samples were different morphologies, via combining with different templates. The luminescence results revealed that the addition of templates have a significant influence on the luminescence properties of ${\mathrm{\text{Eu}}}^{3+}$-doped ${\mathrm{\text{Y}}}_2{\mathrm{\text{O}}}_3$.

Yttria nanoparticles are synthesized by co-precipitation method and as-prepared nanoparticles are annealed at various temperatures. The as-prepared and annealed particles are characterized by X-ray diffraction and transmission electron microscope (TEM). Here we estimated the lattice strain, crystallite size, deformation stress, and deformation energy density for annealed (800°C) yttrium oxide nanoparticles by Williamson-Hall-Isotropic Strain Model (W-H-ISM), W-H-Anisotropic Strain Model (W-H-ASM) and W-H-Energy Density Model (W-H-EDM) based on W-H plot from powder X-ray diffraction data. The shape and size of the nanoparticles are determined using TEM. The results of the estimated crystallite size of yttria nanoparticles by various methods agreed with the TEM results.

Blue–green-emitting Y₂O₃ : $x$Bi${}^{3+}$ ($x$ = 0.25–1.50 mol.%) phosphors were synthesized by a solution combustion method followed by high temperature annealing. The effect of Bi${}^{3+}$ ion concentration on the crystal structure and photoluminescence performance of the phosphors were investigated. The results show that the cell parameter and cell volume of Y₂O₃host were increased with the Bi${}^{3+}$ concentration, and all the phosphor powders exhibited porous lamellar structure with the width of $\sim$500 nm. The emission spectra of the phosphors (${\lambda }_{ex}$ = 335 nm) consist of three broadband emission spectra centered at 370 nm (³A${}_u\to {}^1$A${}_g)$, 410 nm (³E${}_u\to {}^1$A${}_g)$ and 486 nm (³B $\to {}^1$A), respectively. The phosphor exhibited the optimal luminescence performance at $x$= 0.50% and the dipole–dipole and quadrupole–quadrupole interactions among Bi${}^{3+}$ ions could lead to the concentration quenching. The color coordinates of Y₂O₃:0.50%Bi${}^{3+}$ were (0.1595, 0.2250), indicating that the as-synthesized blue–green phosphors have a broad application prospect in the field of white light-emitting diodes.

Innovating dosimetric materials, which includes design and development of new dosimetric materials based on rare earth oxides, is challenging. Yttrium oxide (Y${}_{\mathrm{\text{2}}}$O${}_{\mathrm{\text{3}}})$ is one of the most important sesquioxides and presents crystal characteristics that enable doping with rare earth ions, making it a promising material for radiation dosimetry. This paper reports on the development and measurement of Electron Paramagnetic Resonance (EPR) signal response for Y${}_{\mathrm{\text{1.98}}}$Eu${}_{\mathrm{\text{0.02}}}$O${}_{\mathrm{\text{3}}}$micro rods that have undergone facile low-pressure hydrothermal synthesis and bio-prototyping. As- synthesized powders with narrow sub-micrometer particle size distribution with d${}_{\mathrm{\text{50}}}$ of 584 nm exhibited a reactive surface, which led to the formation of stable aqueous suspensions by controlling the surface charge density of particles through alkaline pH adjustment. Ceramic samples with dense microstructure were formed by sintering at 1600 ${}^{\text{o}}$C for 4h at ambient atmosphere. Y${}_{\mathrm{\text{1.98}}}$Eu${}_{\mathrm{\text{0.02}}}$O${}_{\mathrm{\text{3}}}$micro rods were irradiated using a ${}^{\mathrm{\text{60}}}$Co source with doses from 1 to 100 kGy, and EPR spectra were measured at room temperature in X-band microwave frequencies. Sintered samples exhibited linearity of the main EPR signal response from 10 Gy to 10 kGy. Supralinearity was observed for higher doses, which is possibly ascribed to formation of more defects. Using europium as a dopant enhanced the EPR signal of yttrium rods remarkably, due to 4f–4f transitions of the Eu${}^{\mathrm{\text{3+}}}$ ion. These innovative findings make europium-doped yttrium oxide a promising material for radiation dosimetry.