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BACKGROUND: Many recent studies have found that zirconia co-doped with TiO2 and GeO2 exhibits excellent superplasticity. OBJECTIVE: To investigate the improvement of anti-cryogenic aging properties of zirconia materials stabilized by 3% yttrium oxide co-doped with TiO2 and GeO2. METHODS: The 3% yttrium oxide stabilized zirconia material samples co-doped with GeO2 and TiO2 were prepared by mechanical ball milling, drying, and pressure free sintering. Among them, the mole percentage of 3% yttrium oxide stabilized zirconia was 98%. The mole percentages of TiO2 powder (purity 99.8%) and GeO2 powder were 1.5% and 0.5%, respectively, which was recorded as the 1.5Ti-0.5Ge group. The mole percentages TiO2 powder (purity) 99.99%) and GeO2 powder were 1% and 1%, respectively, which was recorded as 1Ti-1Ge group. The mole percentages of TiO2 powder (purity 99.8%) and GeO2 powder were 0.5%, 1.5%, respectively, which was recorded as 0.5Ti- 1.5Ge group. The microstructure of all samples was investigated by scanning transmission electron microscopy and energy spectroscopy. After treatment in an autoclave, the conversion of all samples was measured by an X-ray diffractometer. RESULTS AND CONCLUSION: (1) Scanning transmission electron microscopy results showed that the composite powders of a 3% yttrium oxide stabilized zirconia material co-doped with GeO2 and TiO2 had uniform particle size and were distributed over a 50 nm; the particle shape was basically spherical and well dispersed, but there was a small amount of agglomeration. X-ray diffractometer exhibited that the Ge4+, Ti4+ stabilizers could inhibit the low-temperature aging effect of zirconia materials. With the increase of the doping amount of GeO2, the low-temperature aging resistance of zirconia could be improved. Energy spectrometer detection demonstrated that with the increase of dopant content, the degree of grain boundary segregation increased, but even if the doping amount of Ge4+ was small, the degree of grain boundary segregation could be comparable to that of Ti4+ with a large amount of doping. (2) The results suggest that the addition of GeO2 and TiO2 improved 3% yttrium oxide stabilized zirconia ceramics against low-temperature aging properties. GeO2 is superior to TiO2 in resisting low-temperature aging and can be used as the first choice. [ABSTRACT FROM AUTHOR]

This article presents electrolytic deposition of thin Rare Earth (RE) coatings on Crofer 22 APU stainless steel substrates for high temperature applications, such as interconnects in solid oxide cell stacks. The deposition of coatings based on yttrium-, gadolinium-, lanthanum-, and cerium nitrates is discussed. The high temperature corrosion properties of surface-modified steels were examined using thermogravimetry and electrical resistivity measurements. Coatings and oxide microstructures were examined by XRD and SEM of surfaces and cross-sections. The results showed that the use of the RE element oxide layers reduced the growth of oxide scale, as evidenced by lower weight gain. The layers based on Y- and Gd-oxides showed the best corrosion protection properties. The electrical measurements showed that the surface-modified samples had lower resistance than the uncoated sample. • New technique of obtaining thin ceramic layers - electrolytic technique. • Electrolytic deposition of cerium, gadolinium, lanthanum and yttrium oxide layers. • Thin ceramic layers, on the order of tens of nanometers. • Reduction of the thermogravimetric weight gain of samples covered with a ceramic layer. • Electrical measurements showed that the surface-modified samples had lower resistance than the uncoated sample. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to examine the corrosion and flexural behaviour of advanced hybrid aluminium matrix nanocomposites (HAMNCs) made with a vacuum-assisted stir die casting (two-layer feeding) and reinforced with titanium oxide (TiO2) and yttrium oxide (Y2O3) nanoparticles. The previous researchers have shown that TiO2 and Y2O3 nanoparticles make aluminium composites much more resistant to corrosion and wear. Design/methodology/approach: Salt spray corrosion tests were done on the samples over time as well as the pre-and post-corrosion morphology of the test samples was also investigated. The density, porosity and energy dispersive X-ray of the fabricated samples were observed. Findings: It was observed that a lower corrosion rate of 0.127 mils/year and 0.573 mils/year was seen in the Al/5 Wt.%TiO2/5 Wt.%Y2O3 (HAMNC1) and Al/7.5 Wt.%TiO2/2.5 Wt.%Y2O3 (HAMNC3), respectively. It was evident from the results that the pores and densities of the samples varied with the filler concentrations and matrix filler wettability. HAMNC1 has the lowest values of density and porosity at 2.568 g/cm3 and 9.91%, respectively. At the same time, a significant improvement in the flexural strength of 72 N/mm2 was also seen in the HAMNC1 configuration. Practical implications: The proposed hybrid samples are well suited for aerospace and automobile structural components such as brake drums, discs, engine cylinders and fins. Originality/value: The mixed influence evaluation of TiO2 and Y2O3 nanoparticles with pure Al on composite samples has not been studied. This research aims to examine the combined influence of nanoparticles on the corrosion aspects of two-step feeding vacuum stir casted products, as well as their morphology. [ABSTRACT FROM AUTHOR]

Highly compact green bodies are usually required to fabricate transparent or translucent polycrystalline yttrium oxide. The present work reports on the fabrication of highly dense (ρ rel >98%) translucent Y 2 O 3 from low-density green bodies by exploiting a high sinterability of nano Y 2 O 3 powder. A commercial nano Y 2 O 3 , with a crystallite size of ca. 30 nm, was shaped by uniaxial pressing and, afterwards, densified by pre-sintering at 1500 °C followed by hot isostatic pressing. The coarsening tendency of yttria nanoparticles causes the rearrangement of particles and results in the high sinterability of nano Y 2 O 3 even at low green densities. This improves the packing density and enables sintering to high densities, eliminating pores, and, thus, obtaining translucent Y 2 O 3. [ABSTRACT FROM AUTHOR]

We study the impact of yttrium oxide (Y 2 O 3) on the optical properties of iron-doped borate glasses. A series of borate glasses, with a diluted and constant amount of Fe 2 O 3 , doped with various amounts of Y 2 O 3 (labeled as BNaFeY-glasses) was prepared and studied. The impact of Y 2 O 3 doping on the optical transitions of BNaFeY-glasses was studied by analyzing the optical absorption spectra. The presence of Fe cations, with their Fe3+ state, leads to the appearance of absorption in the ultraviolet region. Furthermore, the optical transmittance spectra proved the transparency of all BNaFeY-glasses. Moreover, the transmittance of the sample with the highest Y 2 O 3 content is about 93 % within the visible range. Because of the diluted Fe content within BNaFeY-glasses, the five absorption bands of Fe are not observed. So, these bands are detected by magnifying the spectra within the visible region. These bands are labeled ʋ 1 , ʋ 2 , ʋ 3 , ʋ 4 and ʋ 5 at wavelengths 454.5, 518.4, 652.5, 707 and 808 nm respectively. These bands were used to calculate the crystal field splitting (10Dq) for all BNaFeY-glasses. The outstanding 10Dq increment with further Y 2 O 3 doping was explained in terms of more interactions between Fe cations and their surroundings. On the other side, the shielding parameters were considered to examine the competence of these transparent glasses against nuclear radiation. We found that the sample doped with the highest amount of Y 2 O 3 has the highest linear attenuation coefficient and the lowest half-value layer (HVL). From the HVL results, we need a thickness of 3.646 cm from the sample with 5 mol% of Y 2 O 3 to get protection from 50% of the photons with energy of 0.662 MeV, and this thickness is increased to 5.137 cm when the energy is 1.333 MeV. [ABSTRACT FROM AUTHOR]

Single crystal superalloys are the preferred materials for manufacturing turbine blades of advanced aero-engines, due to their excellent high temperature comprehensive performance. The interfacial reaction between alloys and ceramic mould are an important factor to influence the surface quality and service performance of the turbine blade. It is very important to reveal the interfacial reaction mechanism to improve turbine blade quality and yield rate. In this paper, the interfacial reactions between DD6 single crystal superalloy and ceramic mould were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The results show that the main reaction products were HfO2, Al2O3 and Y3Al5O12 when the yttrium oxide powders were the prime coat materials, while alloy surface suffered undesirable sand fusion; the thicknesses of the reaction layers were over 20 μm. The reaction layer can be divided into two layers, the layer close to the alloy was mainly composed of Al2O3 and Y3Al5O12, and the layer close to the mould was composed of SiO2, Al2O3 and Y3Al5O12. Avoiding the formation of Y2O3-Al2O3-SiO2 ternary low-melts can solve the interfacial reaction between DD6 alloy and yttrium oxide mould. [ABSTRACT FROM AUTHOR]

In this study, the effect of adding Dy 2 O 3 on the microstructure and mechanical properties of zirconia-toughened alumina (ZTA) stabilised by yttrium oxide was investigated. ZTA-Dy 2 O 3 composites with different Dy 2 O 3 contents (0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt%) were prepared by sintering at 1600 °C for 4 h. The phases and structures of the samples were characterised through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dy 2 O 3 formed a solid solution c-DYZ with YSZ, and an appropriate amount of Dy 2 O 3 could refine the grains and contribute to densification. The densities, hardness, flexural strength and toughness all increased and then decreased with increasing Dy 2 O 3 content, reaching maximum values of 99.2%, 1741 ± 19 HV, 449 ± 10 MPa and 5.87 ± 0.42 MPa‧m1/2, respectively, at 3 wt% Dy 2 O 3 content. [ABSTRACT FROM AUTHOR]

The effects of laser parameters on the microstructure and properties of plasma-sprayed yttrium oxide coating on the graphite matrix were investigated. Tensile strength, porosity, roughness, and scratch meter tests were carried out to evaluate the critical load and mechanical properties of the coating after spraying and laser micro-melting. When the porosity and surface roughness of the coating are minimum, the critical load of the coating is 7.85 N higher than that of the spraying surface. After laser micromelting, the crystal phase of Y2O3 coating surface does not change, the crystallinity is improved, and fine grain strengthening occurs. When the laser power density is 75 W/mm2, the scanning speed is 30 mm/s, and the defocusing distance is 40 mm, the film base bonding performance and wear resistance of the material reach the maximum value. The failure of Y2O3 coating is mainly due to the degradation of mechanical properties such as film base bonding strength, surface porosity, and surface roughness, which leads to the local collapse of the material. The coating after laser micro-melting only presents particle disintegration at the end of the scratch area. [ABSTRACT FROM AUTHOR]

Sintered tungsten electrode materials with different proportions of lanthanum oxide, yttrium oxide and zirconia were prepared by solid liquid doping, isostatic pressing and intermediate frequency sintering. The effects of different proportions of lanthanum oxide, yttrium oxide and zirconia on the microstructure, second phase particle distribution and macroscopic mechanical properties of the samples were investigated. The results show that the addition of lanthanum oxide, yttrium oxide and zirconia can effectively improve the distribution of the second phase particles in the tungsten matrix,reduce the over enrichment of the second phase at the grain boundary, and improve the comprehensive mechanical properties of tungsten electrode materials. When the mass ratio of lanthanum to yttrium zirconium is 3; 1; 1,the material shows optimal comprehensive mechanical properties, the density can reach 96. 04%,the microhardness can reach 549. 37 HVo.3, and the compressive strength can reach 3 785 MPa. The reason is that under this ratio, the second phase particles are the smallest and uniform, the dispersion degree is the highest, and the refinement effect on the matrix grain is also optimal which is the average grain size of tungsten matrix is 10. 3μm. [ABSTRACT FROM AUTHOR]

Due to their appropriate physicochemical properties, nanoparticles are used in nanomedicine to develop drug delivery systems for anticancer therapy. In biomedical applications, metal oxide nanoparticles are used as powerful and flexible multipurpose agents. This work described a green synthesis of Y2O3 nanoparticles (NPs) using the sol-gel technique with the use of aqueous leaf extracts of Lantana camara L (LC). These nanoparticles were characterized with the aid of different methods, including UV, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), transmitted electron microscopy (TEM), and photocatalytic degradation. Y2O3 nanoparticles showed excellent antibacterial activity against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli with a 10 to 15 mm inhibitory zone. Green Y2O3 NPs were released with a 4 h lag time and 80% sustained release rate, indicating that they could be used in drug delivery. In addition, the bioavailability of green Y2O3 NPs was investigated using cell viability in cervical cancer cell lines. These green-synthesized Y2O3 NPs demonstrated photocatalytic degradation, antibacterial, and anticancer properties. [ABSTRACT FROM AUTHOR]

Powder mixtures based on Si3N4 nanoparticles and yttrium and aluminum oxides were prepared. Ceramic samples with a relative density of 95–96% have been produced by spark plasma sintering at a pressure of 80 MPa and a heating rate of 50°C/min. The microstructure of the samples has been shown to be formed by Si2N2O grains ~0.7 μm in size, with an amorphous oxide phase in between. The highest hardness (13.3 GPa) was reached by the sample containing the Y2O3 and Al2O3 oxides in the molar ratio 2 : 1 and obtained at a sintering temperature of 1770°C. [ABSTRACT FROM AUTHOR]

Due to the rapid development of China's regeneration industry, secondary aluminium ash (SAA) has been extensively produced. The reuse of SAA and Y2O3 doping was studied in this research. This proved that SAA can turn into a raw material for gehlenite/magnesia-alumina spinels. Furthermore, doping with Y2O3 can aggrandize the densification feature of gehlenite/magnesia-alumina spinels. The densification of the gehlenite/magnesia-alumina spinel without Y2O3 was lower than that of the doped spinel in the temperature range of 1573 to 1773 K. At 1673 K, 3 wt% Y2O3 was added to the gehlenite/magnesia-alumina spinel. It had a density of 2.05 g·cm−3 and a compressive strength of 91.2 MPa. Generally, 3 wt% Y2O3 was added, and the sintering temperature at 1673 K was appropriate. The elevation of the densification feature was also attributable to the solubility of Y2O3 and the formation of a low-viscosity liquid phase such as YCaAl3O7. The SAA can be reused for the recovery of gehlenite/magnesia-alumina spinels. Doping it with Y2O3 can broaden its reutilization in new water-resistant ceramic materials. [ABSTRACT FROM AUTHOR]

Sintered blanks for spherical rolling bodies of silicon nitride ceramics were obtained by addition of an yttrium-containing organoalumoxane, i.e., an organoelement oligomer, that was soluble in traditional organic solvents and converted during pyrolysis into an aluminum-yttrium oxide sintering additive with a given mass ratio Al2O3/Y2O3 = 3/1. Studies conducted using thermogravimetry, x-ray phase analysis, and optical and scanning electron microscopy showed that features of the use of the elementoxane instead of aluminum- and yttrium-oxide sintering additives were a uniform distribution of aluminum and yttrium oxides in Si3N4 ceramics and the chemical activity of the pyrolysis products of organoyttriumoxanealumoxane (OYA), including amorphous nanoscale oxides on the surface of the Si3N4 powder. The density, porosity, microstructure, and degree of purity of the polished surface of the obtained ceramic indicated it was promising for use as a blank for high-quality rolling bodies. [ABSTRACT FROM AUTHOR]

Mode-locking is an ultra-short pulse laser generation technique. The range of pulse duration may vary from picoseconds to femtoseconds. Yttrium Oxide (Y2O3) based saturable absorber (SA) was appropriately revealed in the mode-locked method within the 1.55-micron regime. Y2O3 is perfect for strength, melting point, and chemical stability and can be used as a laminated insulator due to its properties. Moreover, Y2O3 also owns broadband service, switching speed, and engineering features. The Y2O3-PVA film was produced by combining the 50 mg Y2O3 powder into a 50 mL polyvinyl alcohol (PVA) solution and stirring it at room temperature for about 24 h. A mode-locked pulse was recorded with the integrated Y2O3-PVA SA in the erbium-doped fiber laser (EDFL) cavity, and the output spectrum optical spectrum analyzer displayed was around 1560.66 nm. In addition to the sustained mode-locked pulse, a nearly constant repetition rate of 1.01 MHz at a specific pump power begins from 175.87 mW to 228.04 mW while the pulse duration is 4.15 ps. Lastly, the mode-locked pulse had been evaluated, which showed the peak power started from 4.94 kW to 6.07 kW. [ABSTRACT FROM AUTHOR]

The tribological properties of ceramic coating often fall short of expectations because of their inherent brittleness and internal microcracking and weak bonding strength. Gradient materials containing different Yttrium oxide stabilized zirconia ceramics (YSZ) and NiCrAlY were prepared at 1050 °C using discharge plasma sintering technique. Two interlayers consisting of different content of YSZ and NiCrAlY was located between the top YSZ and the NiCrAlY substrate, and the layers obtain good bonding. The microstructure and tribological properties of the ZrO 2 -based gradient-structured material were investigated. The element distribution on the surface of the sample after sintering was relatively homogeneous without obvious segregation. Nanoscratch tests indicate that the YSZ based layer obtains high coefficient of friction than the NiCrAlY layer. The tribological results suggested that the coefficient of friction decreases gradually with the increase of load, adhesive wear and oxidative wear were the main wear mechanisms, the formed oxidized layer rich of Zr and Ag contribute to the reduced coefficient of friction under different loads. [ABSTRACT FROM AUTHOR]

• First-time review paper based on B-type Y 2 O 3. • Studied various synthesis routes in preparing monoclinic Y 2 O 3. • Theoretical studies published are covered. • Luminescence capability of the material is explored. • Biological applications of the material were also investigated. Research on monoclinic Y 2 O 3 has been limited, not because of a lack of potential applications, but rather due to challenges associated with synthesizing phase-pure material. The limited understanding of the material and its properties has hindered researchers from further exploring this compound. Some studies suggest that the B-type polymorph of Y 2 O 3 exhibits superior performance compared to its cubic counterpart. Additionally, there are reports indicating the existence of simple synthesis techniques that could potentially overcome the material's significant disadvantage highlighted by many researchers, namely, complex synthesis routes. To date, no comprehensive reports have summarized the key findings related to B-type Y 2 O 3. In this effort, we aim to provide an exhaustive overview of research conducted on this polymorph. This includes an examination of diverse synthesis techniques employed by researchers, theoretical studies conducted on the material, an exploration of its luminescence properties, and an overview of various applications studied thus far. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • TiSiN suggested an alternative electrode due to its improved mechanical strength. • Zr-silicate formation degrades dielectric properties of ZrO 2 films on TiSiN. • Y 2 O 3 passivation suppresses Si diffusion in TiSiN/ZrO 2 capacitors. • Y 2 O 3 contributes tetragonal phase formation of ZrO 2. • High k value maintained even at 4 nm ZrO 2 thickness with Y 2 O 3. This study investigates the degradation and improvement of the dielectric properties of ZrO 2 -based metal-insulator-metal (MIM) capacitors using TiSiN electrodes. As dynamic random-access memory (DRAM) design rules scale down, the mechanical properties of TiSiN electrodes provide advantages over conventional TiN, but also introduce challenges due to Si diffusion into ZrO 2 films, forming low-dielectric constant (k) Zr-silicate and defect-related dielectric degradation. We evaluate the dielectric properties of ZrO 2 films on TiSiN electrodes and identify significant reductions in the dielectric constant and an increase in DC and AC non-linearity due to Zr-silicate formation. To mitigate these problems, a Y 2 O 3 passivation layer is introduced between the TiSiN electrode and ZrO 2 dielectric film. Physical and chemical analyses, including X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), confirm that Y 2 O 3 passivation effectively suppresses Si diffusion, preventing formation of Zr silicate, and preserving the high- k tetragonal phase of ZrO 2. Electrical measurements show that the Y 2 O 3 layer significantly improves the dielectric constant and reduces non-linearity effects. Notably, even at a reduced ZrO 2 thickness of 4 nm, a relatively high k value is maintained with Y 2 O 3 passivation. This study concludes that the Y 2 O 3 passivation layer is indispensable for maintaining high dielectric performance in ZrO 2 -based MIM capacitors with TiSiN electrodes, ensuring stability and efficiency in advanced DRAM applications. [ABSTRACT FROM AUTHOR]

Erbium oxide (Er 2 O 3)-doped optical fibers (EDF) are well-known for their applications in optical amplification at 1550 nm. In this study, we present the synthesis of Er 2 O 3 -doped yttrium oxide (Y 2 O 3) nanoparticles (NPs) using a homogeneous coprecipitation technique and their integration into optical fibers for enhanced optical amplification. A series of NP samples with varying Y/Er molar ratios were synthesized to identify the optimal composition for incorporation into optical fibers. X-ray diffraction (XRD) analysis revealed that the nanoparticles crystallize in a cubic geometry (space group Ia3) with crystallite sizes ranging from 20 to 41 nm. These sizes increased approximately to 90 nm as the calcination temperature was raised from 1000°C to 1400°C. Field emission scanning electron microscopy (FESEM) corroborated the XRD results, while high-resolution transmission electron microscopy (HRTEM) confirmed the crystalline structure and an average particle size of approximately 100 nm. Photoluminescence studies showed that emission and excitation intensities were functions of the Y/Er molar concentration ratio and calcination temperature, with the lifetime extending up to 6.86 ms for a sample with a 0.25:0.01 Y 2 O 3 :Er 2 O 3 ratio calcined at 1400°C. To assess the performance of the synthesized NPs, an optical preform was prepared using the Vapor Phase Delivery (VPD) method combined with the Solution Doping (SD) technique. The preform was then drawn into fiber, and its amplification performance was evaluated. The resulting fiber demonstrated efficient amplification with a gain of 14.9 dB with respect to 0 dBm input signal at 1550 nm under 150 mW pump power from 9 m active fiber, indicating its potential as a gain medium for constructing erbium-doped fiber amplifiers (EDFAs). • Er 2 O 3 doped Y 2 O 3 nanoparticle (NP) has been synthesized with variation of Y/Er molar concentration ratio (0.1:0.01 to 0.50:0.01). • The effect of calcination temperature (1000 °C–1400 °C) is critically analyzed using X-ray diffraction (XRD) characterization technique to calculate the crystallite size and to optimize the composition ratio. • Photoluminescence (PL) characterization is carried out to identify the effect of Y/Er molar concentration ratio and calcination temperature. • The optimized NP has been incorporated through Vapor Phase Delivery (VPD) - Solution Doping (SD) technique to fabricate an optical fiber. • The fabricated optical fiber shows numerical aperture (NA) of ∼0.14 and exhibits amplification performance with a gain of 14.9 dB. [ABSTRACT FROM AUTHOR]

The continuous utilization of ultraviolet (UV) light sources within both academic and industrial contexts necessitates the imperative advancement of alternative UV sources to replace hazardous mercury lamps. Herein, we proposed a mercury-free narrowband UVB (NB-UVB)-emitting device from Y 2 O 3 :Gd3+ nanofilm on a tubular quartz substrate. The nanofilm is fabricated utilizing the spin-coating sol-gel precursor technique and is subsequently synthesized via a high-annealing temperature solid-state reaction. This synthesis resulted in the formation of a single-phase cubical structure of Y 2 O 3 characterized by a crack-free morphology. The NB-UVB radiative output with a peak at 315 nm is generated through vacuum UV-induced photoluminescence originating from the emission of Xe excimer, which subsequently excites the Gd3+ luminescent centers incorporated within the Y 2 O 3 host matrix. Moreover, in a high-voltage bipolar power system operating at 19 kV and 19 kHz, the device exhibited an NB-UVB radiance output of 1.34 mW, accompanied by a power efficiency of 0.02 %, whilst preserving exceptional temporal performance. Thus, this investigation introduces an innovative perspective on a mercury-free NB-UVB-emitting device, thereby promoting further exploration into the application of UV radiation sources derived from excimer lamp technology. • A mercury-free narrowband-UVB-emitting device is presented using gadolinium-doped yttrium oxide nanofilm. • The optimum Gd3+ content is investigated for efficient excimer operation. • The nanofilm exhibits vacuum UV excitation characteristics, suggesting its potential application in narrowband-UVB emission facilitated by a xenon excimer lamp. • The device performance, reliability, and post-operation morphology are examined to evaluate the practicality and prospects. [ABSTRACT FROM AUTHOR]

Air plasma spraying (APS) is widely used for preparing superhydrophobic rare earth oxide (SH-REO) coatings due to its advantages of capable for large-scale and fast deployment with low cost. However, the origin of the superhydrophobicity remains unclear, which has impeded the design and development of robust APS-deposited SH-REO coatings. In this work, by studying APS-deposited superhydrophobic yttrium oxide (SH-Y 2 O 3) coatings, we found a close correlation between oxygen vacancy and surface adsorbed species. Our results suggest that oxygen vacancy introduced during APS makes the Y 2 O 3 surface liable to the adsorption of nonpolarized, hydrocarbon molecules, which contributes to a low-energy surface. Therefore, we showed the crucial role of oxygen vacancy in the acquirement of reliable SH-REO coatings. [ABSTRACT FROM AUTHOR]

The D2Σ+-X2Σ+ electronic absorption spectrum of the astrophysically relevant yttrium oxide (YO) molecule has been recorded for the first time in the 400-440 nm region using laser induced fluorescence. YO molecules are produced by corona discharge of oxygen between the tips of two yttrium needles in a supersonic jet expansion. Anunambiguous spectroscopic identification of theD2Σ+-X2Σ+ transition becomes possible from a combined analysis of the moderate-resolution laser excitation spectrum and dispersed fluorescence spectrum. We have also performed multi-state complete active space second order perturbation theory calculations on the first six doublets of YO, and the results support our assignment of the D2Σ+ state. Accurate spectroscopic constants for D2Σ+ v' = 0 and 1 levels have been determined from a rotational analysis of the high resolution spectra that are recorded with a resolution of ~0.018 cm-1. Severe perturbations are observed in the experimental spectra and are considered to originate from interactions with at least one nearby 2/4Σ electronic state, e.g., the undetected C2Π state. We have also measured the radiative lifetimes of B2Σ+ v0 = 0, and D2Σ+ v' = 0 and 1 states, based on which the B2Σ+-X2Σ+ (0, 0) and D2Σ+-X2Σ+ (0/1, 0) band oscillator strengths have been determined. [ABSTRACT FROM AUTHOR]

The nickel-based superalloys prepared by additive manufacturing (AM) commonly exhibit inferior mechanical properties at high temperatures, particularly in terms of ductility and creep resistance, compared to the corresponding conventional manufactured (CM)alloys, and this significantly hinders the widespread application of AM nickel-based superalloys in the aerospace industry. To address this problem, a novel nickel-based superalloy for additive manufacturing, Hastelloy X-AM (HX-AM), using the yttrium (Y) alloying strategy has been developed in this work. The results show that the Y element is present in the matrix as Ni 5 Y phase and yttrium oxide nanoparticles after laser additive manufacturing, exerting a significant inhibitory effect on the precipitation and coarsening of detrimental second phases at grain boundaries (GBs) during subsequent heat treatment or service processes. The HX-AM alloy exhibits an exceptional matching relationship between strength (ultimate tensile strength = 315 ± 3 MPa) and ductility (total elongation = 56 ± 1.7 %) at 900 °C. What's more, the creep performance of HX-AM alloy is significantly improved simultaneously compared with CM Ni-based alloys at 900 °C, overcoming the longstanding challenge of inferior creep performance in AM nickel-based superalloys at high temperature. The fatigue lifetime of HX-AM alloy reaches 295.6 h at 900 °C/40 MPa, showing over fifteenfold enhancement compared to that of CM Hastelloy X alloy. [ABSTRACT FROM AUTHOR]

The editors announces the retraction of the article "Aqueous room temperature mono-dehydration of sugar alcohols using functionalized yttrium oxide nanocatalysts" by J. Yang and colleagues.

Binder jetting additive manufacturing (BJAM), a combination of liquid binder and solid powders, was widely utilized to fabricate complex–structured alumina (Al 2 O 3) ceramic cores. However, the high porosity, high brittleness and low mechanical strength of Al2O3 ceramics generally limit their industrial applications. To balance the contradiction between porosity and bending strength and improve the fracture toughness of Al2O3 ceramic core, sodium silicate (Na2O·3.2SiO2) solution and 5 mol% yttrium oxide stabilized zirconia (5YSZ) nanopowders were selected as densifier and toughening phase in this study. By means of the vacuum infiltration and sintering process, the effects of Na2O·3.2SiO2 contents, sintering temperatures and 5YSZ amounts on porosity, bending strength, and fracture toughness of Al2O3 ceramic were systematically investigated. Results show that the porosity and fracture stress of Al 2 O 3 infiltrated with 30 wt% Na 2 O·3.2SiO 2 solution sintered at 1550 ℃ reached 21.4±1.1% and about 52.7 MPa, respectively. When the amounts of 5YSZ in 30 wt% Na 2 O·3.2SiO 2 solution were increased from 0 wt% to 6 wt% and the sintering temperatures were varied from 1400 ℃ to 1550 ℃, the fracture toughness of Al 2 O 3 ceramic gradually enhanced to the maximum value of 2.8185±0.071 MPa/m1/2 obtained at 4 wt% 5YSZ and 1550 ℃, which was increased by 87.44% compared with the infiltrated sample without 5YSZ. Therefore, using BJAM technology to fabricate a strong–tough Al 2 O 3 ceramic cores for the turbine blades casting could realize short process and efficient preparation of the ceramic cores, which had a great theoretical foundation and application potential in the casting field. [Display omitted] • A strong and tough Al 2 O 3 ceramic core was fabricated by binder jetting technology. • Porosity and bending strength of Al 2 O 3 were adjusted by infiltrating sodium silicate. • Toughness of Al 2 O 3 was increased by adding 5 mol% yttrium oxide stabilized zirconia. • Experimental results expand the toughening research of BJAM Al 2 O 3 ceramic. [ABSTRACT FROM AUTHOR]

A known issue for future nuclear reactors is helium accumulation inside the steel structure materials, responsible for structural issues such as embrittlement and cracking. One possible solution is using new types of reinforced steel, such as oxide dispersion strengthened (ODS) steel. It consists of adding oxide nanoparticles to the Fe-based material, especially yttrium oxide (yttria, Y 2 O 3), improving its properties. Therefore, one first step is understanding the helium diffusion inside this system. Very little is known about helium inside yttria, with most studies being theoretical ones. Based on this context, this work proposes a combined theoretical and experimental multiscale approach to investigate helium diffusion inside yttria. The theoretical approach starts with the density functional theory, used to model the atomic yttria cell and determine helium insertion sites. The transitions between the sites were described using the Nudged Elastic Bond (NEB) method. Kinetic Monte Carlo was then employed to obtain the interstitial diffusion coefficient expression for the first time for this material. It showed a limited diffusion at temperatures below 600 K, which may indicate a tendency for He to be blocked in the oxide. Then, the charged vacancies were explored. It showed that the vacancy further reduces helium diffusion. Finally, it was demonstrated that helium spreads across different vacancies and interstitial sites. The experimental part involved implanting helium ions at 50 keV in samples with nanometric or micrometric grains. Then, the specimens were characterised with transmission electron microscopy (TEM) and thermo-desorption spectroscopy (TDS) techniques. TEM did not evidence detectable bubbles even at the highest studied fluence (1 × 1016 cm−2). The TDS highlighted different mechanisms for helium diffusion and the grain size's role, providing a novel model for diffusion coefficient calculation based on interstitial diffusion. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a common neurodegenerative disorder characterized by progressive cognitive decline. Yttrium oxide nanoparticles (Y 2 O 3 NPs) have recently attracted much attention for their potential anti-inflammatory and antioxidant properties. However, the effects of Y 2 O 3 NPs in animal models of AD are less studied. This study aimed to investigate the potential therapeutic effects of Y 2 O 3 NPs in streptozotocin (STZ)-treated rats, a reliable animal model of AD, with special emphasis on cognitive function, neuroinflammation, and mitochondrial biogenesis in the hippocampus. Male Wistar rats were stereotaxically injected with STZ (3 mg/kg, 3 µl/ventricle). Three weeks after STZ injection, cognitive function was assessed using the Morris water maze, elevated plus maze, and passive avoidance tasks. Intraperitoneal treatment with Y 2 O 3 NPs (0.1, 0.3, or 0.5 mg/kg) was started 24 h after the STZ injection and continued for 21 days. The mRNA and protein levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) and components involved in mitochondrial biogenesis (PGC-1α, NRF-1, and TFAM) were measured in the hippocampus. The results indicated that STZ induced cognitive impairment and led to neuroinflammation and mitochondrial biogenesis impairment in the hippocampus of rats. Interestingly, treatment with Y 2 O 3 NPs effectively reduced STZ-induced cognitive deficits in a dose-dependent manner, possibly by attenuating neuroinflammation and mitochondrial biogenesis impairment. These findings suggest that Y 2 O 3 NPs can be considered as a promising therapeutic agent for treating or ameliorating the neuropathological effects associated with AD. [ABSTRACT FROM AUTHOR]

[Display omitted] • The phosphors were synthesized according to precursor technology using Y 1-x (Er/Yb) x (HCOO) 3. • The crystal structure of ytterbium formate was established for the first time. • The (Y 0.9 Er 0.02 Yb 0.08) 2 O 3 sample exhibited the strongest reddish-orange color luminescence. The (Y 0.9 Er 0.1-x Yb x) 2 O 3 (x = 0, 0.02, 0.05, 0.07, 0.08, 0.09) and Y 1-(0.02+y) Er 0.02 Yb y O 3 (y = 0.05, 0.07, 0.09, 0.11) solid solutions have been synthesized by the precursor technique using mixed anhydrous formates. The crystal structure of ytterbium formate, Yb(HCOO) 3 , was established for the first time. The structural parameters and phase purity of the synthesized precursors and oxides were determined by X-ray phase analysis. The average sizes of crystallites are in the 60–80 nm range. The upconversion spectra of solid solutions exhibit a weak green and an intense red line attributed to 2H 11/2 ,4S 3/2 →4I 15/2 and 4F 9/2 →4I 15/2 transitions of Er3+ ions. The green and red emissions of (Y 0.9 Er 0.1-x Yb x) 2 O 3 and Y 1-(0.02+y) Er 0.02 Yb y O 3 oxides are caused by two-photon conversion processes. The effect of dopant (erbium and ytterbium) concentration and Er3+/Yb3+ ratio on the intensity of upconversion emission were established, the contribution of upconversion green luminescence decreases with increasing the ytterbium concentration. [ABSTRACT FROM AUTHOR]

Ti-48Al- x Y (x = 0, 0.1, 0.2, 0.5, 1.0, 1.5, 2.0 at. %) alloys were prepared in a vacuum induction melting furnace using the micro-submicron double-scale yttrium oxide crucible. The microstructure and interfacial reaction between the melt and crucible were charactered, and the mechanical properties of the alloy after melting were tested. The results show that the purity of the double-scale yttrium oxide crucible prepared by the slip casting method is 99%, the linear shrinkage of the crucible is 31%, and the internal pores exist in the gain of the crucible after sintering. After melting, there are no new compounds are formed on the surface of the alloy ingots, which indicates that the crucible does not react with the alloy melt. A small part of Y 2 O 3 is dissolved into the melt, resulting in the formation of Y and O. The active alloy melt absorbs O element, and Y element can contribute to reducing the dissolution of Y 2 O 3. The formation heat and activity coefficient of each alloy element were calculated by the Miedema model. The formation heat of Al Y and Ti Al is negative, while the formation heat of Ti Y is positive. The activity coefficient of Y is the highest of all. As a result, as the Y content increases, the binding force of the Al atom increases, and the binding force of the Ti atom weakens, resulting in a decrease in the melt activity of Ti-48Al- x Y alloys. The microhardness of Ti-48Al- x Y alloys by the double-scale yttrium oxide crucible increases with the increase of Y content. The compressive strength of the Ti-48Al- x Y alloys by the double-scale yttrium oxide crucible increases initially and decreases subsequently with the addition of Y. The total compressive strength is higher compared to the compressive strength of Ti-48Al- x Y alloys by the water-cooled copper crucible. Therefore, the double-scale yttrium oxide crucible is suitable for the melting of TiAl alloys. [Display omitted] • Ti-48Al- x Y alloys were prepared by the double-scale yttrium oxide crucible. • There was no interaction between double-scale yttrium oxide crucible and alloy melt. • The addition of Y to TiAl alloy can help to slow down the dissolution of Y 2 O 3. • Compressive strength of Ti-48Al- x Y alloys did not decrease melted by Y 2 O 3 crucible. • Microhardness of Ti-48Al- x Y alloys increased with the increase of Y content. [ABSTRACT FROM AUTHOR]

This study investigates the deposition process and characterization of yttrium oxide thin films using high-power impulse magnetron sputtering (HiPIMS) and bipolar HiPIMS, which are advanced deposition technologies that can effectively use high energy for controlling energy flux to produce thin films. These two techniques require no heat for the control of phase formation of yttrium oxide thin films. The properties of the films were analyzed using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, ultraviolet–visible spectrometry, and water contact angle analyses. The results indicated that the energy of sputtered species can be effectively tuned by adjusting the process parameters, and it can then be used to achieve phase control of yttrium oxide thin films. The monoclinic phase is associated with a high number of oxygen vacancies in the films. The cubic phase with low oxygen vacancies produces more compact thin films with wide bandgaps. Therefore, the relationship between the process parameters and the resultant structural, morphological, and optical properties as well as the wettability of the deposited films is confirmed. This allows the film properties to be tuned to each application, enabling their use in various fields. • Y 2 O 3 thin films were deposited using HiPIMS and bipolar HiPIMS techniques with no external heating. • The Y 2 O 3 phase is controlled with each parameter of HiPIMS and bipolar HiPIMS. • Growth conditions affect the film surface morphology, optical bandgap, and contact angle. [ABSTRACT FROM AUTHOR]

We describe our study of the treatment of ceramics based on zirconium dioxide (ZrO 2), partially stabilized with yttrium oxide (Y 2 O 3) (5.15 % wt.), by continuous and pulsed electron beams in the forevacuum pressure range. We find that continuous electron beam treatment at certain heating rates can lead to changes in the surface structure, with increase in roughness and change in crystalline phase composition. High heating rate leads to increase in the cubic phase of ZrO 2. The results of irradiation by a pulsed electron beam depends on the pulse energy density and pulse power of the beam, with noticeable changes in the surface characteristics when the energy density reaches about 10 J/cm2; increased roughness of the ceramic surface is observed at this energy density. Further increase in pulse energy density (>10 J/cm2) and/or power can lead to increase in roughness by an order of magnitude. A change in color of the ceramic surface and formation of a layer with a columnar structure is observed when the energy density reaches 21 J/cm2 at a pulse power of 320 kW. These results show the suitability of electron beam treatment for controlled modification of zirconium dioxide ceramic materials. • Treatment by continuous and pulsed electron beams modify surface of ZrO 2 ceramics. • The heating rate of a sample influences on surface structure of zirconia ceramics. • Surface roughness can be changed by varying the parameters of the electron beam. • The layer with a columnar structure on the treated ceramic surface is observed. [ABSTRACT FROM AUTHOR]

Nuclear reactors operating at high temperatures and in harsh environments can benefit significantly from the use of 316L Oxide Dispersion Strengthened (ODS) steel. This steel is particularly suitable due to its excellent machinability, ductility and ability to maintain mechanical integrity at temperatures above 1000 °C. ODS 316L steel achieves its excellent performance through the dispersion of fine, stable oxide particles in the steel matrix. In addition, ODS 316L steel exhibits excellent corrosion and oxidation resistance, further extending its life and reliability under prolonged exposure to high temperatures and radiation. This study aimed to enhance the corrosion resistance of 316L steel by incorporating yttrium oxide (Y2O3) into its matrix. Samples differed in the way the powders were prepared by mechanical alloying (MA). Powder preparation parameters included time: 5, 10 and 50 hours, rotational speed: 250 rpm, with grinding cycles of 15 minutes and 15-minute intervals for diversion. The materials were manufactured using pulse plasma sintering (PPS) and then compared with standard 316L steel rods. The corrosion resistance of the 316L+Y2O3 was investigated, with Y2O3 added in concentrations of 1 wt.% and 3 wt.% in both nano and micro sizes. Electrochemical techniques including corrosion potential measurements, electrochemical impedance spectroscopy (EIS) and potentiodynamic tests in various solutions (0.5M NaCl, 0.5M H2SO4, 0.5M H2SO4+0.5MNaCl) were performed to assess the corrosion properties. Additionally, the surfaces affected by corrosion were analyzed using scanning electron microscopy (SEM) and optical profilometry. [ABSTRACT FROM AUTHOR]

Austenitic stainless steels are promising materials for next generation nuclear reactors due to their excellent mechanical properties and reasonable corrosion resistance compared to ferritic and ferritic-martensitic steels. However, they suffer from lower strength and void swelling resistance. Oxide dispersion strengthening (ODS) addresses these issues by incorporating nano-sized oxides, which pin dislocation motion and prevent grain coarsening, thus enhancing mechanical strength and creep resistance at high temperatures. Additionally, the matrix-oxide interfaces act as sinks for radiation-induced defects, improving swelling resistance. In this study the preparation of oxide dispersion-strengthened austenitic steel 316L involved mechanical alloying of the steel powder with Y2O3. Elemental Y was also introduced to dissolve within the Fe matrix as an alternative method. These powder precursors were then compacted using Spark Plasma Sintering (SPS) and analysed for their microstructure. The mechanical properties of the resulting compacts were assessed, revealing an initial formation of chromium-containing carbides, likely due to carbon diffusion from the graphite tools used. Both Y2O3 and Y were successfully incorporated into a solid solution during mechanical alloying, with precipitation occurring during compaction. The mechanical properties varied based on chemical composition and specific SPS conditions. Homogeneously distributed Y2O3 particles were successfully achieved through this powder metallurgy process. Future research will aim to optimize SPS conditions to prevent carbide formation. [ABSTRACT FROM AUTHOR]

Thin films of pure yttrium oxide (Y2O3) and doped with cerium oxide (CeO2) were prepared by the chemical spray pyrolysis(CSP)method. The structural, optical and electrical properties of the prepared films were investigated. The analysis of Xray diffraction (XRD) thin films revealed that the undoped and doped Y2O3 were amorphous with a broad hump around 27o and narrow humps around 48o and 62o for all samples. Except for the Y2O3:6wt.%CeO2 thin film, all had signal preferential orientation along the (100) plane at 2θ=12.71o which belongs to CeO2, Field emission scanning electron microscopic (FE-SEM) images confirmed the formation of the nanosized particles which resembles circles and others revealed rods and balls shape. UV-Vis spectra study showed peak absorption at a wavelength of 305 nm, with blue shift due to quantum confinement, and this also happened for the doped films, with direct energy band gaps. The photoluminescence spectra (PL) of undoped Y2O3 and doped thin films showed an emission peak at 365 nm at the same wavelength of all the prepared samples with a slight difference. All prepared films show three activation energies except Y2O3:6wt.%CeO2 film has two activation energies. From I-V characteristic curves, the prepared films have Schottky behavior except Y2O3:6wt.%CeO2 film, which displayed ohmic behavior. Y2O3:6wt.%CeO2 fabricated device revealed good photosensitivity for VIS and IR wavelength. [ABSTRACT FROM AUTHOR]

Microstructure and thermal properties of aluminum nitride ceramics are strongly affected by sintering conditions. Reducing sintering environments, which are typically encountered during liquid-phase sintering of aluminum nitride in graphite furnaces, have a particular impact on the distribution of secondary phase and properties in the final ceramic part. In order to gain a deeper understanding of the effect of the sintering atmosphere, a systematic study of sintering conditions during consolidation of aluminum nitride ceramics at 1700 °C containing calcium oxide and yttrium oxide as sintering additives was carried out, varying carbon content in the sintering environment as well as nitrogen partial pressure. Compositional and microstructural changes were clarified employing electron microscopy techniques as well as phase and mass loss analysis. An increased migration of the secondary phase in the presence of reducing species was observed, resulting in a significant change in microstructural evolution, which was shown to affect mechanical as well as thermal properties of the resulting materials. Based on these findings, suitable sintering parameters for aluminum nitride ceramics leading toward consistent reducing conditions are proposed, resulting in materials with a flexural strength of 390 MPa and thermal conductivity of up to 175 W m-1 K−1. Thus, a robust framework for generating materials with well-controllable properties, an essential prerequisite for current and future applications of aluminum nitride in the field of thermal management, is provided. [ABSTRACT FROM AUTHOR]

Lu 3 TaO 7 was prepared through a modified sol-gel technique and high-temperature sintering method to investigate its lattice type, micro-morphology, phase stability, thermal expansion coefficient, and conductivity. The results indicate that the obtained powder and bulk samples are composed of a single fluorite structure. The obtained bulk sample shows a dense microstructure, and uniform element distribution. The thermal conductivity of the Lu 3 TaO 7 oxide slightly increases with temperature due to typical amorphous-like behaviour, which is much lower than those of 7 wt% yttrium oxide–stabilized zirconium oxide (7YSZ) and Sm 2 Zr 2 O 7 ceramics. Furthermore, the enhanced phonon scattering leads to a lower thermal conductivity of Lu 3 TaO 7 than that of Gd 3 TaO 7. The thermal expansion coefficient of the Lu 3 TaO 7 oxide reaches 10.72 × 10−6 K−1 at 1200 °C, which is slightly greater than that of 7YSZ. The outstanding phase stability up to 1200 °C satisfies the requirements for thermal barrier coatings. [ABSTRACT FROM AUTHOR]

Full dense aluminum nitride ceramics (AlN) were prepared by hot-pressing sintering with and without yttrium oxide (Y2O3) as sintering aid. An intensive analysis of the AlN raw powder was performed to identify impurities. AlN grains appeared to be coated of an amorphous layer mainly composed of boehmite-like bonds. Thanks to the sintering process used all samples obtained exhibit high densification rate. The crystalized secondary phases identified by x-ray diffraction belong to the pseudo-binary Al2O3 – Y2O3. During sintering, AlN's native oxide phase, observed on grains surface, plays a key role on formation of yttrium-based secondary phases such as YAM (Y4Al2O9), YAP (YAlO3) and YAG (Y3Al5O12). The formation of secondary phases was investigated thanks to quenching tests at different temperatures from 1400 to 1600 °C. Influence of secondary phases on DC electrical behavior was determined using current leakage measurement. The electrical properties appeared to be more impacted by the presence of these phases than by the densification improvement caused by yttria addition. [ABSTRACT FROM AUTHOR]

Low-temperature sinterable and low-loss composites consisting of La2O3–B2O3–ZnO glass-ceramics and Al2O3 filler have been investigated. The phase composition of LBZ/Al2O3 composites is closely related to the sintering temperature. When the sintering temperature was 850 °C, the main phases included LaBO3 and La(BO2)3 precipitated from LBZ glass-ceramics, ZnAl2O4 and LaAl2.03(B4O10)O0.54 phases generated by interfacial reactions, and Al2O3 filler. The high content of crystalline phases in the composites indicated the low content of residual glassy phases, which was related to the low loss of the composites at high frequencies, especially at microwave frequencies. The initial sintering temperature and the temperature corresponding to the fastest shrinkage speed of LBZ/40A and LBZ/50A composites were related to the content of LBZ glass-ceramics, and all the composites could be densified at low temperatures. Optimum properties were exhibited for the composite of LBZ glass-ceramic with 50 wt% Al2O3 sintered at 900 °C with a permittivity εr = 7.3 and a dielectric loss tan δ = 1.62 × 10−3 (at 12.1 GHz). The low εr and tanδ coupled with a low sintering temperature, suggesting that the LBZ glass-ceramic/Al2O3 composites had potential to meet the requirements of LTCC substrate materials for high frequencies. [ABSTRACT FROM AUTHOR]

Due to the increasing number of applications for ceramic components in reactive etching processes, the interest in the specific erosion behavior of highly etch‐resistant materials like yttrium oxide (Y2O3) has increased in the past years. Despite the large number of investigations already existing in this field, a more general understanding of the erosion mechanisms still lacks due to the limited comparability of these investigations. The huge difference in the kind of etching setups, processing parameters (bias voltage and plasma gas composition), and sample microstructures prevented consistent conclusions so far. To achieve a more general understanding, this study investigates the erosion behavior Y2O3 under a broad spectrum of plasma etching parameters. Therefore, the bias voltage is increased from 50 to 300 V and the plasma gas composition is gradually changed from Ar‐rich to CF4‐rich compositions. This systematic approach allows to directly correlate the morphology changes caused by plasma erosion with the related plasma etching parameters and enables to better understand their influence on the depth of physical and chemical interactions, surface damage, and etching rate. We discovered three distinct erosion regimes, which exhibit specific erosion characteristics. Using these observations, a schematic processing map for Y2O3 was developed, which could help to estimate the severity of the erosion attack dependent on the processing parameters. [ABSTRACT FROM AUTHOR]

Highly transparent cerium‐doped yttria ceramics were fabricated via a pressureless sintering method with an addition of 10 at.% La2O3 and 1 at.% ZrO2 as a binary sintering additive. With an increase in the Ce doping concentration from 0 to 3 at.%, the optical absorption edge of yttria ceramics exhibited a significant red shift from 290 to 380 nm as a result of the 4f–5d transition of Ce3+ and the charge transfer of Ce4+ (i.e., Ce4++e–→Ce3+). For a 2‐mm thick sample doped with 3 at.% Ce, the total ultraviolet radiation (UV) transmittance (220–400 nm) is only 1.7%, indicating a nearly complete UV absorption. Meanwhile, the specimens possess high in‐line transmittance levels in both the visible and the infrared regions (i.e., >70% at 450 nm and ∼80% at 1100 nm). Additionally, the present specimens were confirmed to have good enough mechanical strength levels (∼165 MPa) and thermal conductivity (∼5 W/m·K), which are comparable or even better compared to those of previously reported transparent yttria ceramics. The results of this work indicate that cerium‐doped transparent yttria ceramics are promising candidate materials for full‐band UV‐shielding window applications. [ABSTRACT FROM AUTHOR]

Magnetoelectric (ME) (100-x) Na0.5Bi0.5TiO3 (NBT)–xCoFe2O4 (CFO) (x = 30 and 35) particulate composites were prepared from the pre-sintered individual constituents by adopting mixed oxide route. The composites consisting of CFO grains embedded in a twice-grain-sized NBT matrix were investigated for the enhancement of the ME coefficient. CFO grains are not interlinked which implied that composites are within percolation limit and thereby 0–3 particulates are formed without impurity phase at the interface is evidenced by XRD, SEM micrographs and elemental mapping. Raman modes due to the influence of CFO are visible around 213 cm−1. A non-saturated PE loop indicates leaky behavior and the MH loop depicts the magnetic behavior of samples. ME coefficient is 18.9 mV/cm Oe for the 65NBT-35CFO composite and it is higher than that reported in the NBT–CFO composites. Theoretical modeling of the ME coefficient signifies that the observed experimental value is much smaller than the theoretical value. [ABSTRACT FROM AUTHOR]

Herein, we assess the dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide. The antioxidant properties of these nanoparticles were investigated in three groups of Sprague–Dawley rats (10 per group) exposed to environmental stress daily for 1 week and one control group. Groups 2 and 3 were intravenously injected twice a week with YNPs at 0.3 and 0.5 mg at 2nd and 5th day of environmental stress exposure respectively. Different samples of blood and serum were collected from all experimental groups at end of the experiment to measure oxidative biomarkers such as total antioxidant capacity (TAC), hydroxyl radical antioxidant capacity (HORAC), oxygen radical antioxidant capacity (ORAC), malondialdehyde (MDA), and oxidants concentration as hydrogen peroxide (H2O2). The liver, brain, and spleen tissues were collected for fluorescence imaging and histopathological examination in addition to brain tissue examination by transmission electron microscope (TEM). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to estimate YNPs translocation and concentration in tissues which is consecutively dependent on the dose of administration. Depending on all results, poly EGMP YNPs (poly EGMP yttrium oxide nanoparticles) can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB). Also, the neuroprotective effect of YNPs opening the door to a new therapeutic approach for modulating oxidative stress–related neural disorders. Highlights: • The dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide was assessed. • The dose of administration directly affecting the brain, liver, and spleen tissues distribution, retention, and uptake of YNPs and direct correlation between the absorbed amount and higher dose administered. • YNPs can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB). [ABSTRACT FROM AUTHOR]

In this paper, the thermodynamic properties of yttrium oxide clusters, nano-sized yttrium oxide particles and yttrium oxide crystals were calculated and analyzed based on density functional theory. The multi-scale nucleation and growth model of yttrium oxide inclusions formed by yttrium deoxidation during steelmaking was established. Firstly, the first-principles calculations were carried out by using the yttrium oxide clusters models and the nanometer yttrium oxide particles calculation models. It was found that the thermodynamic properties of the clusters and the nanometer particles changed with the size and temperature basically consistent with the conventional materials, but when the size was small, both of them showed the size-dependent effect. Based on the two-step nucleation theory, a multi-step thermodynamic model of "yttrium oxide reaction → yttrium oxide clusters → yttrium oxide critical crystal nucleus → nanoscale growth → macro yttrium oxide inclusion particles" was established by analyzing the change rule of Gibbs free energy of each structure transformation. [ABSTRACT FROM AUTHOR]

The current study is focused on the microstructure, phase transition, and mechanical properties of the aluminum yttrium oxide (Al–Y2O3) composite material. Microwave hybrid sintering using Y2O3 nanoparticles as reinforcement at various (i.e., 0.5, 2, 3.5 and 5) wt% was used. Simultaneous thermal analysis (STA) and X-ray photoelectric spectroscopy (XPS) were used to investigate the chemical interaction between Al and Y2O3. This research will aid in gaining a better knowledge of the changes in thermal characteristics and compositional changes that occur throughout the microwave hybrid sintering process. The insight into material properties reveals that intermetallic Al3Y and Al2O3 are generated during the synthesis process, which was substantiated by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX) analysis. The Al–Y2O3 composite material has a well-consolidated microstructure and improved mechanical characteristics. To further understand material behaviour, a robust and non-destructive depth sensing nano-indentation technology was being used. With the addition of 5 wt% Y2O3, the microhardness of composite material is enhanced by 1.62 times. Furthermore, with 5 wt% Y2O3, the produced composite's nano hardness and elastic modulus augmented by 2.43 and 1.8 times, respectively. It is caused by the presence of intermetallic in the composite material, as well as the prevalence of uniform reinforcement distribution. [ABSTRACT FROM AUTHOR]

Zirconium oxide (zirconia) ZrO2 is widely used for applications in high-temperature structural materials. In this work, yttria-stabilized zirconia has been studied. Series of specimens of ZrO2 ceramics stabilized with 6, 7, and 8 mol% Y2O3 were prepared using the conventional sintering technique. Four sintering temperatures (1450, 1500, 1550, and 1600°C) were used for the 6% yttria-stabilized zirconia series, and two sintering temperatures (1550 and 1600°C) were used for the 7% and 8% yttria-stabilized ZrO2 series. The tests of microhardness and fracture toughness of the materials were performed by the indentation method. It was found that both the yttria percentage and the sintering temperature affect the mechanical behaviour of the ceramics. The maximum transformation toughening effect during indentation was revealed for the ceramic ZrO2–6 mol% Y2O3. Using the phase balance analysis, it was found that such toughening of ceramics is related to corresponding levels of fracture toughness. [ABSTRACT FROM AUTHOR]