Search

In this paper, Eu3+:(Y0.97Zr0.03)2O3 transparent ceramics with different doping concentrations of Eu3+ were prepared by vacuum sintering. This series of transparent ceramic samples exhibits strong red emission when excited by an electron beam at the keV level. However, color changes observed in the samples after high‐energy electron irradiation. This is due to the capture of electrons by traps related to oxygen vacancies within the Y2O3 lattice. Specifically, under electron beam irradiation, the capture of the electrons by oxygen vacancy‐related defects in the Y2O3 lattice occurs, leading to radiation damage. The color change can be suppressed to some extent by the incorporation of Zr4+ into the Y2O3 lattice, which can effectively suppress the generation of oxygen vacancies. Interestingly, samples with heavy doping of Eu3+ exhibit stronger resistance to electron irradiation damage. Based on the detailed characterizations, including optical transmittance, cathodoluminescence, photoluminescence, thermoluminescence and luminescence decay time, it is found that under heavy doping conditions, Eu3+, which has a stronger cationic character than Y3+ can more effectively suppress the generation of electron traps induced by the oxygen vacancies and the interstitial oxygen in the Y2O3 lattice, thereby enhancing radiation resistance. This research can advance the understanding of defect suppression mechanisms and benefit the application of Y2O3‐based functional transparent ceramics in high‐energy electron and β‐ray irradiation environment. [ABSTRACT FROM AUTHOR]

Hydrogen production from the decomposition of ammonia is considered an effective approach for addressing challenges associated with hydrogen storage and transportation. However, their relatively high energy consumption and low efficiency hinder practical multi‐scenario applications. In this study, Y2O3‐stabilized catalysts with Co‐loaded onto porous nitrogen‐doped carbon (Y2O3–Co/NC) are synthesized by pyrolysis of Y(NO3)3‐modified ZIF‐67 under an inert atmosphere, followed by annealing in a reducing environment. The introduction of Y2O3 enhanced the recombination and desorption of N atoms and facilitated the gradual dehydrogenation of NHx on the catalyst surface, resulting in improved catalytic activity for the thermal decomposition of ammonia. Benefitting from the electron‐donating properties of Y2O3 and N‐doped carbon, the optimized catalyst achieved a remarkable NH3 conversion efficiency of 92.3% at a high gas hourly space velocity of 20 000 cm3·gcat−1${\mathrm{g}}_{{\mathrm{cat}}}^{ - {\mathrm{1}}}$·h−1 with an encouraging H2 production rate of 20.6 mmol·gcat−1${\mathrm{g}}_{{\mathrm{cat}}}^{ - {\mathrm{1}}}$·min−1 at 550 °C. Moreover, the synthesized catalyst undergoes a fast‐dynamic reconstruction process, resulting in exceptionally stable catalytic activity during the thermal decomposition of ammonia, rendering it a promising candidate for carbon‐free energy thermocatalytic conversion technology. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusion Clinical Significance To evaluate the effect of staining, glazing, and polishing of stabilized zirconia with 5 mol% of yttrium oxide (5Y‐TZP) on the wear behavior of opposing tooth enamel.The plane specimens of 5Y‐TZP were divided into 6 groups (n = 10), according to surface treatment: as sintered, staining, glazing, polishing, staining followed by glazing, and staining followed by polishing, and positioned against tooth enamel during the two‐body wear test (20 N, 2 Hz, until completing 300,000 cycles). The wear rates of tooth enamel were evaluated using a profile projector and a digital pachymeter as a measure of vertical height loss. The data were analyzed by one‐way ANOVA and a Tukey post hoc test (α = 0.05).Polishing reduced the vertical height loss (p < 0.001) while there was no difference among other groups.Polishing is recommended as a finishing procedure to reduce the wear rates of tooth enamel, and finishing procedures (glazing or polishing) performed after staining did not affect the vertical height loss of tooth enamel.Polishing is the recommended finishing procedure for preshaded 5Y‐TZP to reduce the wear rates of opposing tooth enamel. Staining is applied to the occlusal surface to reproduce the pigmented groove appearance, and glazing or polishing performed after staining did not affect the wear rates of opposing tooth enamel. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling (PDRC) presents a promising avenue for efficient thermal management without relying on electrical power. In this study, the potential of integrating Hollow Yttrium‐Oxide Spheres (HYSs) within a Polydimethylsiloxane (PDMS) matrix to enhance PDRC is investigated. Through a combination of experimental characterization and computational analysis, the optical properties and radiative cooling performance of PDMS films embedded with HYSs are evaluated. These results demonstrate that HYSs significantly improve both solar reflectivity and long‐wave infrared (LWIR) emissivity of the PDMS matrix. Finite‐Difference Time‐Domain (FDTD) simulations confirm the scattering efficiency of HYSs across various wavelength ranges, highlighting their effectiveness as additives for enhancing the radiative properties of passive cooling materials. Experimental validation reveals enhanced reflectivity and emissivity of PDMS films with embedded HYSs, resulting in superior cooling performance compared to non‐HYS counterparts. Overall, this study underscores the potential of HYS‐infused PDMS films as a promising solution for passive radiative cooling, with broad applicability in diverse domains requiring efficient thermal management solutions. Additionally, these research insights pave the way for establishing an AI database for passive radiative cooling research, offering new avenues for further exploration and application in this field. [ABSTRACT FROM AUTHOR]

Topological constraint theory (TCT) and molecular dynamics simulations (MD) are utilized to study the effect of Y2O3/SiO2 substitution on the short‐ and medium‐range structures and properties in aluminosilicate glasses containing Y2O3. Experimental methods have been applied to characterize the structures of the as‐prepared glasses to verify the accuracy of MD simulations. It was found that the Y–O bond distance is around 2.38 Å and the Y average coordination number is around 5.78. The introduction of Y2O3 disrupts the Si–O and Al–O bonds in the network structure and elevates the proportion of non‐bridging oxygen. Meanwhile, the calculation results of Si–O and Al–O bond distances show Y shortens the distance between Si, Al cations and oxygen ions, improving the network structure tightness. Furthermore, the glass transition temperature (Tg), Vickers hardness (HV), and elastic modulus (E) of glass increase with the increase of Y2O3 content, while the viscosity decreases. TCT was used to analyze the relationship among glass compositions, structures, and properties, and the properties prediction models for Tg, HV, and E were established. The effectiveness of TCT prediction models was proved by the comparison between the results predicted by the models and the data reported in the literature. [ABSTRACT FROM AUTHOR]

This report presents a new application for yttrium oxide (YOX) in the modification of carbon paste electrodes with excellent electroactivity for the independent detection of dopamine (DA) and ascorbic acid (AA). The surface of the YOX‐modified electrode was characterized with SEM and EDS. The electroactive properties of DP and AA were studied with cyclic voltammetry (CV), square wave voltammetry (SWV) and amperometry (Am). The activity of DA and AA increased by more than 100 % when YOX/CPE was used, which allowed us to obtain detection limits of 0.04 and 0.06 μmol/L for DA and AA, respectively. The usefulness of YOX/CPE was tested with real human urine, fresh orange juice and vitamin C tablets, and the results were acceptable. [ABSTRACT FROM AUTHOR]

Yttrium oxide (Y2O3)$( {{{\mathrm{Y}}}_2{{\mathrm{O}}}_3} )$ has the potential to be used as a host material for creating polycrystalline transparent ceramics (PTCs). This paper presents an experimental study on opto‐electrical properties of Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$ using zirconium oxide (ZrO2)$( {{\mathrm{ZrO}}_2} )$ and lanthanum oxide (La2O3)$({\mathrm{La}}_2{{\mathrm{O}}}_3)$ as sintering aids via the co‐precipitation technique. The sintering aids improve the properties, sintering process, and lower the sintering temperature. Five different compositions of Y2O3(((Y1−xZr0.02Lax)2O3),wherex=0,3,6,and9at.%)${{\mathrm{Y}}}_2{{\mathrm{O}}}_3\ ( {({{( {{{\mathrm{Y}}}_{1 - x}{\mathrm{Zr}}_{0.02}{\mathrm{La}}_x} )}}_2{{\mathrm{O}}}_3} ),{\mathrm{\ where\ }}x = 0,\ 3,\ 6,{\mathrm{\ and\ }}9{\mathrm{\ at}}.{\mathrm{\% }})$ were synthesized and they were then used to analyze for their structural, morphological, physio‐chemical, and electrical characteristics. For the system studied, the addition of ZrO2${\mathrm{ZrO}}_2$ and La2O3${\mathrm{La}}_2{{\mathrm{O}}}_3$ does not change the phase of pure Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$, but an increase in the crystal and grain size from 31.2$31.2$ to 42.5nm$42.5{\mathrm{\ nm}}$ and 10.2 µm to 16.4 µm was noticed. The thermal characterization over thermogravimetric analysis/differential thermal calorimetry (TGA/DSC) determines the temperature at which pure Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$ undergoes a phase transition, specifically over 700°C. A reduction in the band gap due to strain induced by the dopant resulted in a decrease in energy from 5.54$5.54$ to 4.8eV$4.8{\mathrm{\ eV}}$. The dielectric constant of Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$ doped with 9at.%La$9{\mathrm{\ at}}.{\mathrm{\% \ La}}$ exhibits a significant increase of ∼50%${\sim}50\%$. [ABSTRACT FROM AUTHOR]

Hydrogen production from the decomposition of ammonia is one of the promising methods to solve the problem of hydrogen storage and transportation. Currently, ruthenium‐based catalysts are widely recognized as highly active catalysts for ammonia decomposition reactions. Here, Ru nanoparticles (NPs) on yttrium oxide derived from yttrium carbonate precursor (c‐Y2O3) was successfully prepared by the impregnation method. A hydrogen production rate up to 31.5 mmol gcat−1 min−1 can be obtained over the 5% Ru/c‐Y2O3 catalyst at 450 °C with a weight hour space velocity (WHSV) of 30000 mL gcat−1 h−1, and the activity is stable during a test period of 120 h. The catalysts were characterized by a series of techniques such as TEM, CO‐chemisorption, XPS, and CO2‐TPD. Characterization results reveal that high metal dispersion of Ru NPs, strong metal support interaction, high concentration of oxygen vacancies, and suitable basicity of Ru/c‐Y2O3 catalyst all strongly influence on the catalytic performance in ammonia decomposition. NH3 temperature‐programmed surface reaction (NH3‐TPSR) results indicate that a strong NH3 adsorption activation and binding desorption of nitrogen ability on the surface of Ru/c‐Y2O3 catalysts are also beneficial for the high activity. These results provide a reference for the design of efficient Ru‐based ammonia decomposition catalysts for hydrogen production by tuning the precursor of Y2O3 support. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusion Clinical Significance The purpose of this in vitro study was to evaluate the effect of staining, glazing, and polishing on the survival probability of monolithic crowns manufactured with preshaded stabilized zirconia with 5 mol% of yttrium oxide (5Y‐TZP).Monolithic crowns in the shape of an upper canine (1.5 mm of thickness) were manufactured by CAD/CAM, adhesively cemented on metallic foundation, and divided into 6 groups (n = 21): C (control), S (staining), G (glazing), P (polishing), SG (staining and glazing), and SP (staining and polishing). The survival probability was determined by step‐stress accelerated life testing with a load applied to the palatine concavity of the crown. First, the specimens were subjected to a single‐load to fracture test (SLF) and next to the fatigue test (5 Hz, thermocycling immersed in water varying 5–55°C), including the light (n = 9), moderate (n = 6), and aggressive (n = 3) loading profiles (load ranged between 20% and 60% of SLF). The survival probability was calculated considering the cycles for failure (CFF) and fatigue failure load (FFL) and illustrated using a Kaplan–Meier graph. The comparison among groups was performed using a Log‐Rank test (α = 0.05).The mean value of SLF was 586.7 N. There was no difference among groups in survival probability, considering CFF and FFL.Staining, glazing, and polishing can be performed safely without damaging the mechanical behavior of 5Y‐TZP monolithic crowns.Staining is used to characterize and improve the esthetic of zirconia monolithic crowns. It can be used to reproduce the color gradient in the cervical region of the crown and pigmented grooves. This study showed that staining, glazing, and polishing did not affect the survival probability and the use of finishing procedures (glazing or polishing) after staining did not improve the survival probability of zirconia monolithic crowns. [ABSTRACT FROM AUTHOR]

Purpose: The sintering technique and cooling strategy influence the strength of zirconia. This study examined the impact of altering the cooling rate of glass‐infiltrated monolayer and multilayer 5 mol% yttria‐partially stabilized zirconia (5Y‐PSZ) on their strength. Materials and Methods: One‐hundred eighty (180) specimens (width × length × thickness = 10 × 20 × 2 mm) were prepared using monolayer (Mo: Cercon‐xt) and multilayer (Mu: Cercon‐xt ML) 5Y‐PSZ. Randomly distributed specimens (n = 15/group) were sintered with traditional (T) versus glass infiltrated (G) technique and cooled down with different cooling rates: slow (S: 5°C/min), normal (N: 35°C/min), and fast (F: 70°C/min). Four‐point bending test was used to measure flexural strength (σ). Microstructures were investigated by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X‐ray diffraction (XRD). Three‐way ANOVA and Tamhane comparisons were determined for a significant difference of σ (p < 0.05). Weibull analysis was determined for Weibull modulus (m). Results: The highest σ (MPa) was seen for GMuS (696.8 ± 69.8). Mo‐PSZ and Mu‐PSZ showed no significant difference in σ. G‐sintering presented significantly higher σ (659.9 ± 79.3) than T‐sintering (426.0 ± 63.7). S‐cooling (560.9 ± 126.1) had the highest σ. The highest m‐value was observed in GMuN (12.1 ± 3.8). A significant difference in σ was indicated due to cooling rates and sintering techniques (p < 0.05). Conclusions: Glass infiltration significantly enhanced strength through elastic gradience. F‐cooling reduced grain size, impaired grain boundary integration, and increased the tetragonal to monoclinic phase transition, significantly decreasing flexural strength in traditional sintering. Nevertheless, F‐cooling was recommended for glass‐infiltrated 5Y‐PSZ to enhance strength while reducing processing time. [ABSTRACT FROM AUTHOR]

In recent years, multifunctional applications of the same material have gained wide recognition in various fields. The present study reports the synthesis, characterization, and multifunctional applications of europium (Eu)‐doped yttrium oxide (Y2O3) nanophosphor. Synergistic optimization of Eu‐doped Y2O3 results in enhanced photoluminescence (PL) and triboelectric nanogenerator (TENG) performance. Eu‐doped Y2O3 nanophosphors are synthesized using an autocombustion method, and comprehensive characterizations are conducted. The investigations indicate that the Eu doping significantly influences the PL intensity, with the highest emission observed at 3 mol% for powders. The synthesized nanophosphors are blended with silicone to fabricate hybrid films, which are utilized for energy harvesting applications using TENG technology. The TENG devices fabricated with these hybrid films demonstrate a notable relationship between the Eu concentration and the electrical output, achieving peak performance at 1 mol% Eu doping. The maximum output voltage of ≈535 V, short‐circuit current of ≈38 μA, and power density of 800 mW m−2 are observed. Further, TENG is demonstrated in a self‐powered UV photodetector application. The present results contribute to the improvement of sustainable energy technologies and open up a new window for multifunctional materials. [ABSTRACT FROM AUTHOR]

Steels strengthened by alloying elements and precipitates typically maintain their enhanced properties up to the ferrite‐austenite transformation. However, oxide dispersion strengthened ferritic steels are creep resistant even at much higher temperatures given by dispersions of nanosized oxides. To ensure homogeneous dispersion of the oxides, powder metallurgy is used for preparation of the original material. The presented study investigates the effects of direct consolidation of powder of ferritic steel strengthened with yttrium oxide nanoparticles. The powders were mechanically alloyed and sealed into evacuated steel containers, which were subjected to gradual hot consolidation via the industrially applicable intensive plastic deformation method of rotary swaging. Investigations assessing the effects of several reduction ratios showed that the direct consolidation of the oxide dispersion strengthened steel was successful – in the macroscale – at the swaging ratio of 1.03; the quality of consolidation further increased with increasing swaging ratio. At the swaging ratio of 1.83, the consolidated bulk material featured ultra‐fine grains characterized with high angle grain boundaries, homogeneous dispersion of oxide precipitates, and the average Vickers microhardness of 706.6 HV 1. [ABSTRACT FROM AUTHOR]

The development of highly active and robust non‐noble‐metal electrocatalysts for alkaline hydrogen evolution reaction (HER) at industrial‐level current density is the key for industrialization of alkaline water electrolysis. Herein, a superhydrophilic self‐supported Ni/Y2O3 heterostructural electrocatalyst is constructed by a high‐temperature selective reduction method, which demonstrates excellent catalytic performance for alkaline HER at high current density. Concretely, this catalyst can drive 10 mA cm−2 at a low overpotential of 61.1 ± 3.7 mV, with a low Tafel slope of 52.8 mV dec−1. Moreover, it also shows outstanding long‐term durability at high current density of 1000 mA cm−2 for 500 h in 1 m KOH, evidently exceeding the metallic Ni and Pt/C(20%) catalysts. The superior HER activity can be attributed to the multi‐interface engineering of the Ni/Y2O3 electrode. Construction of Ni/Y2O3 heterogeneous interface with dual active sites lowers the energy barrier of water dissociation and optimizes the hydrogen adsorption energy, thus synergistically accelerating the overall HER kinetics. Also, its superhydrophilic self‐supported electrode structure with the firm electrocatalyst‐substrate interface and weakened electrocatalyst‐bubble interfacial force ensures rapid charge transfer, prevents catalyst shedding, and expedites the H2 gas bubble release timely, further enhancing the catalytic activity and stability at high current density. [ABSTRACT FROM AUTHOR]

Atomically distributed transition metal coordinated with nitrogen is considered as a class of promising oxygen reduction reaction (ORR) catalyst. However, the challenge of ineffective distribution of Fe‐Nx active sites have been long existing, leading to low active site density and unstable performance, which needs be overcome for next generation ORR electrocatalysts. Herein, yttrium (Y) is introduced into atomically dispersed iron (Fe) nitrogen co‐doped carbon materials to integrate nanoparticles, nanoclusters, and atomic sites, which endow the Fe‐N4‐Y2O3 and Fe4N0.94‐Y2O3 (FeY‐NC) with outstanding ORR activity. The FeY‐NC achieves half‐wave potential of 0.926 and 0.809 V in alkaline and acidic condition, respectively. The kinetics current density at 0.9 V in alkaline condition is 31.2 mA cm−2, which is 7.8 times of Fe‐NC and 32.4 times of Pt/C. This outstanding activity of FeY‐NC is enabled by the generated atomic FeN4 and Fe4N nanoparticles dual active‐sites, and further the synergistic effect between the Fe‐Nx/Fe4N0.94 with Y2O3 nanoclusters are loaded on nitrogen‐doped carbon (NC) network. The superior performance of FeY‐NC is demonstrated in a primary Zinc‐air battery, deliver a peak power density of 233 mW cm−2. [ABSTRACT FROM AUTHOR]

Europium‐doped yttrium oxide (Y2O3:Eu3+) is one of the main red‐emitting luminescent materials currently used in light‐emitting devices owing to its high luminous efficiency, high color purity, and other excellent optical characteristics. However, Y2O3:Eu3+ is hydrophilic, which is a major obstacle to its long‐term application in high‐humidity outdoor environments. Hydrophobic modification is a viable solution to this problem, and can give Y2O3:Eu3+ many excellent properties and functions, such as self‐cleaning ability, anti‐static performance, oil/water separation functions, and corrosion resistance. This study reports the preparation of hydrophobic Y2O3:Eu3+ particles modified with nonfluorinated alkyl silanes. Several influencing factors, including the length of the carbon chain in the silane coupling agent, the pH value of the reaction system, the reaction temperature, and the ratio of reactants, on the hydrophobicity of the prepared samples are studied in detail, and the optimal conditions are determined. A superhydrophobic Y2O3:Eu3+ material with a water contact angle of 151.6° is finally obtained. Moreover, FTIR, TG, SEM, XPS, XRD, and PL are used to explore the mechanism of the hydrophobic modification and the structural and fluorescence performance changes imparted by this modification. [ABSTRACT FROM AUTHOR]

The influence of microwave sintering on the densification, mechanical performances, microstructure evolution and hydrothermal ageing behaviour of pure 3 mol % yttria‐stabilised tetragonal zirconia polycrystalline (3Y‐TZP) ceramics was compared with conventional sintered samples. Green bodies were sintered via conventional pressure‐less and microwave sintering method between 1200 °C to 1400 °C with dwelling time and firing rate at 120 min, 10 °C/min and 1 min, 20 °C/min. Result showed that reduced processing temperature and holding time is possible with microwave sintering technique for fabricating good resistant zirconia sample with bulk density, Young's modulus, and Vicker's hardness that are comparable to samples sintered with conventional method. However, the microwave sintered samples suffered from hydrothermal ageing where their average grain size is above critical size. The enhancement of hydrothermal ageing resistance of the sintered samples is associated with the decreasing grain size of the sintered samples instead of sintering method. [ABSTRACT FROM AUTHOR]

The industrial applications of luminescent coatings for temperature sensing and high‐security QR codes have multiple inherent problems in their application (speed, cost, industrial feasibility) or properties (poor adhesion, chemical, thermal stability, or thermal contact). Luminescent coatings created by the electrochemical Plasma Electrolytic Oxidation (PEO) process have superior properties and can be grown directly within minutes, but are limited to the number of possible luminescent dopants. Having the unlimited possibility for doping on the PEO coatings would provide for superior coatings in all industrially appealing features. Herein, it is shown that adding any luminescent powder results in its partial dissociation and incorporation of its constituents, while it also gets incorporated as a whole. In this manner, alumina coatings are grown with various combinations and concentrations of divalent samarium and europium, and yttrium oxide with trivalent europium ions. These polycrystalline coatings whose microhardness is next to that of the diamond produce intense luminescence in the blue and red regions. Al2O3:Eu2+/Sm2+/3+ + Y2O3:Eu3+ coatings show an excellent temperature sensing performance from the cryogenic up to the high temperatures. Ultimately, the proof‐of‐concept of the luminescent QR code by the electrochemical process is realized creating a highly secure code with unprecedented environmental stability. [ABSTRACT FROM AUTHOR]

Rh‐promoted YZr‐supported Ni catalyst (5Ni/YZr) is investigated for DRM and characterized with X‐ray diffraction, Raman, infrared spectroscopy, cyclic reduction–oxidation–reduction temperature programmed experiment, thermogravimetry, and transmission electron microscope. Over 5Ni/YZr, some active sites become inactive under the CO2 stream and limit H2 yield to ∼71%. Upon 4 wt% Rh addition over 5Ni/YZr; more than one type of stable active sites (Rh and Ni) generates, moderate basic sites are enhanced, wide ranges of CO2‐interacted surface species (especially bidentate CO2‐adsorbed species) are grown and graphitic carbon proportion over spent catalyst declines. This resulted in 87.35% H2 yield and 86.73% CO yield up to 420 min. 5Ni4Rh/YZr catalyst maintains ∼80% H2 yield at the end of 27 h of DRM reaction. [ABSTRACT FROM AUTHOR]

In this paper, Al2O3‐TiC ceramic composites with intragranular nano‐ZrO2 were prepared in vacuum by spark plasma sintering (SPS). The effect of ZrO2 particles with different nano‐sizes on the microstructure and mechanical properties of ceramics was studied. The results show that SPS can achieve relative densification of materials without generating new impurity phases. At the same time, the sintering densification temperature of ceramic materials can be reduced by adding ZrO2 (20 nm) particles. Under the action of SPS strong electric field, the nano‐ZrO2 adsorbed on the surface of the matrix particles can enter the interior of matrix grains, and form intragranular nanostructures when the grain boundaries move and the particles merge. The microstructure and mechanical properties of ceramic materials can be improved through the intragranular structure formed by nanoparticles. The main reasons for the increased strength and toughness of ceramic materials are crack deflection, crack bridging and transgranular fracture. [ABSTRACT FROM AUTHOR]

The oxides with Al2O3‐containing and/or Y‐containing are introduced into 9Cr ferritic/martensitic steel fabricated by vacuum casting to modify its microstructures and improve its mechanical properties. The results show that the micron nonmetallic particles are refined, and the number of submicron particles is increased after the introduction of Al2O3‐containing oxides, while the number of submicron particles is decreased when both Al2O3‐and Y‐containing oxides are introduced. The average grain size, the width of martensite, and the M23C6 phases in the tempered steel are optimized when the Al2O3‐containing oxides are introduced. However, with the further introduction of Y‐containing oxides, these tempered microstructures do not change much, except for the precipitation of the δ‐Fe phase. Due to the grain refinement and second‐phase particle strengthening after the introduction of Al2O3‐containing particles, the tensile strength is improved not only at room temperature but also at 550 °C, but the impact energy drops significantly, which is caused by a large number of TiN particles promoted by Al2O3 particles through heterogeneous nucleation. At the same time, the further introduction of Y‐containing oxides reduces the tensile strength and increases the elongation at room temperature, which is attributed to the precipitation of soft δ‐Fe promoted by the addition of Y. [ABSTRACT FROM AUTHOR]

Finding a robust catalytic system for hydrogen production via dry reforming of methane (DRM) remains a challenge. Herein, MNi0.9Zr1−xYxO3 (M = Ce, La, and La0.6Ce0.4; x = 0.00, 0.05, 0.07, and 0.09) catalyst was prepared by the sol–gel method, tested for DRM and characterized by surface area and porosity, X‐ray diffraction, H2‐temperature programmed reduction, thermogravimetry, and transmission electron microscopy. In La0.6Ce0.4NiO3 catalyst, the substitution of Ni by 0.1% Zr results in a constant high catalytic activity (83% hydrogen yield at 800°C) due to the presence of reducible "NiO‐species interacted strongly with the support" (stable metallic Ni over reduced catalyst) and redox input by ceria phase for laying instant lattice oxygen during lag‐off period of CO2. Substitution of Ni by Zr and Y in the CeNiO3 catalyst system nurtures Ni3Y (providing highly stable metallic Ni for CH4 decomposition) and cerium yttrium oxide phases (providing strong redox input). CeNi0.9Zr0.01Y0.09O3 shows 85% H2 yield at 800°C. [ABSTRACT FROM AUTHOR]

SiAlONs are a class of liquid‐phase sintered ceramics with excellent room‐temperature strength and toughness, but whose residual grain boundary glass softens at high temperatures, limiting use in extreme environments. For this reason, efforts are made to minimize the volume of the grain boundary glass while still facilitating full densification. This work describes a potential route for the densification of SiAlONs with very low concentrations of liquid‐phase sintering additive (e.g., rare‐earth oxides such as yttria) by using an organometallic precursor. Solid solution of Al and O in the Si3N4 lattice was accomplished through the incorporation of solute atoms via liquid organic precursor aluminum sec‐butoxide (ASB). Al2O3 powder is conventionally used for this purpose, and the subsequent lattice softening associated with the solid solution helps to facilitate densification. However, a liquid‐phase additive is still essential for the full densification of SiAlONs. Higher densities were obtained from SiAlON powder blends utilizing organometallic ASB than those utilizing alumina powder, allowing for greater densification at very low Y2O3 concentrations. The thermal decomposition of the organic precursor was investigated by high‐temperature scanning electron microscopy, thermogravimetric analysis, and various X‐ray diffraction experiments. Immersion density measurements and lattice parameter refinements were performed for samples sintered with varying Y2O3 concentrations and/or dwell times. Results indicate that ASB‐containing powder blends favor SiAlON formation more strongly than Al2O3‐containing powder blends and favor densification at very low Y2O3 concentration. [ABSTRACT FROM AUTHOR]

The study was conducted to investigate the apparent digestibility coefficients (ADC) of nutrients in commonly used protein sources for largemouth bass. A reference diet and test diets with 70% reference diet and 30% feedstuff were formulated with yttrium oxide as a digestibility indicator. Overall, the ADC of dry matter of tested protein ingredients was 69.5%–96.4%, and the ADC of dry matter in animal protein sources was significantly higher than in the other five plant protein sources. The ADC of crude proteins ranged from 89.1% to 97.3% for all tested feedstuffs. The ADC value of total amino acids in the tested ingredients is consistent with that of the protein. The ADC of crude lipid of tested ingredients ranged from 45.4% to 96.2%, and the lowest and highest values were observed in porcine haemoglobin powder and pet‐grade poultry by‐product meal, respectively. The ADC of total phosphorus of animal protein ingredients, except porcine haemoglobin powder, was significantly higher than that of plant protein ingredients, except fermented soybean meal. The results revealed the difference in availability of nutrients in plant and animal protein sources for largemouth bass, which could provide a theoretical basis for the selection of protein sources of commercial feed for largemouth bass. [ABSTRACT FROM AUTHOR]

This is the second in a two‐paper series concerning the quantitative characterization of nanocrystalline materials using an electron‐diffraction‐based approach, in which a full‐pattern fitting Rietveld‐based refinement is applied to electron powder diffraction data in transmission electron microscopy (TEM). Part I [Sinha et al. (2022). J. Appl. Cryst.55, 953–965] established a standard calibration protocol to determine the instrumental effects, with special emphasis on the camera length and the diameter of the selected area apertures. Possible application cases are now considered to demonstrate the capabilities of the approach, including the evaluation of the phase composition of TEM specimens, an operation that reveals new application fields for this powerful materials characterization technique. In this regard, different types of material specimen are examined: nanocrystalline yttrium oxide, silicon, titanium dioxide and debris from disc brake wear, each one featuring specific aspects to be tackled with the proposed methodology. To demonstrate the limits of the proposed approach as concerns the material characteristics, an analysis of a hematite sample obtained from the heat treatment of natural goethite, displaying a relatively coarse crystallite size, is performed and a critical discussion of the results is given. [ABSTRACT FROM AUTHOR]

This study is aimed at evaluating the apparent digestibility coefficients (ADC) of six novel protein sources in Pacific white shrimp (Litopenaeus vannamei), including black soldier fly larvae meal (BSFLM), Chlorella vulgaris meal (CM), cottonseed protein concentrate (CPC), Tenebrio molitor meal (TM), Clostridium autoethanogenum protein (CAP), and methanotroph (Methylococcus capsulatus, Bath) bacteria meal (BPM). The control diet (CD) was formulated to contain 448.8 g/kg crude protein and 71.8 g/kg crude lipid. Then, six experimental diets were formulated to contain 70% CD and 30% test ingredients. The yttrium oxide was used as an exogenous indicator for apparent digestibility detection. Six hundred and thirty healthy and uniform-sized shrimp (approximately 3.04 ± 0.01 g) were randomly distributed into triplicate groups of 30 shrimp and they were fed three times daily. After the shrimp was acclimating for one week, their feces were collected 2 hours after the morning feeding until sufficient samples were available for compositional analysis to calculate apparent digestibility. The apparent digestibility coefficients for a dry matter of diets (ADCD) and ingredients (ADCI) as well as the apparent digestibility coefficients for crude protein (ADCPro), crude lipid (ADCL), and phosphorus (ADCP) of test ingredients were calculated. Results showed that the growth performance of shrimp fed BSFLM, TM, and BPM diets significantly decreased compared to that fed the CD (P < 0.05), and no significant differences were found among those fed CD, CM, CAP, and CPC diets (P > 0.05). There were no significant differences in survival among each group (P > 0.05). As for the diets, results showed that the ADCD of BSFLM, CM, CPC, and TM diets was significantly lower than that of CD, while that of the CAP diet was significantly higher than that of CD (P < 0.05) and there were no significant differences between BPM and CD diets (P > 0.05). As for the test ingredients, the ADCPro and ADCL of BSFLM, CM, CPC, and TM were significantly lower than those of CD in Litopenaeus vannamei (P < 0.05). The ADCPro of CAP was significantly higher than that of CD (P < 0.05), but no significant differences were found in ADCL between CAP and CD (P > 0.05). The ADCPro of BPM was significantly lower than that of CD (P < 0.05), but there were no significant differences in ADCL between BPM and CD (P > 0.05). The ADCP of CM, CAP, and BPM were significantly higher than that of CD, while that of BSFLM was significantly lower than that of CD (P < 0.05), and no significant differences were found in ADCP between TM and CD (P > 0.05). To conclude, newly developed protein sources such as single-cell protein (CAP, BPM, and CM) showed great potential as a fishmeal alternative, and insect protein meals (TM and BSFLM) were less effective for shrimp compared to the CD. Although the utilization of CPC by shrimp was lower than other protein sources, it had been much improved compared to the untreated cottonseed meal. The present study will contribute to the application of novel protein sources in shrimp feeds. [ABSTRACT FROM AUTHOR]

Summary: This work targets the design of a novel composite nanomaterial (NCM) based on the exchange of electro current between magnesium oxide and yttrium oxide on the surface of the synthetic self‐assembly (graphene oxide/carboxymethyl cellulose) for supercapacitors, biosensors, and photocatalytic. The different techniques utilize for the characteristic synthesized NCM such as morphology, optical properties, and structural evidence. The electrochemical behaviors and the optical properties perform emphasize the improvement of the electron transfer via the incorporation of the two metal oxides on the surface of the self‐assemble. The photocatalytic efficiency records at 85% after 80 min, and the rate constant documents at 4 × 10−3 min−1 due to the ease of the oxygen reactive species generation for removing the pollutants. The impedance spectroscopy data emphasize the development of the surface and electron transfer that enable it to be a promising candidate for supercapacitors applications. The capacitance value of CNM has been documented at 58.81 nF/cm2, also the biosensor applications for glucose and D‐galactose are detected by UV–Vis spectroscopy and the electrochemical method. From the results, the CNM is a promising candidate for water treatment membrane, supercapacitors manufacture, and biosensors applications. [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]

In this study, the apparent digestibility coefficients (ADCs) of 13 animal‐based feedstuffs were determined for a common aquaculture fish, the Orange‐spotted Grouper Epinephelus coioides. The feedstuffs included five kinds of fish meal (white fish meal [WFM]; low‐temperature‐steam‐dried brown fish meal [LTSBFM]; domestic flame‐dried fish meal; imported flame‐dried fish meal; miscellaneous fish meal [MFM]), two kinds of blood meal (spray‐dried hemoglobin meal; dried‐blood meal [DBM]), and six kinds of animal by‐product meal (chicken meal; meat and bone meal; pork meat meal; fermented feather meal [FFM]; hydrolyzed feather meal [HFM]; shrimp meal). Experimental diets were composed of reference diet at 699 g/kg, yttrium oxide at 1 g/kg (as a tracer), and each tested feedstuff at 300 g/kg. The ADCs of dry matter, crude protein, lipid, gross energy, phosphorus, and amino acids were determined for each experimental diet by the fecal sedimentation method. Overall, the ADCs of dry matter, crude protein, lipid, energy, phosphorus, and amino acids had ranges of 61.39–76.72, 72.23–91.96, 60.75–91.56, 45.20–88.45, 39.61–76.20, and 70.39–96.71%, respectively. The protein ADCs of the WFM (91.96%) and LTSBFM (91.28%) diets were significantly higher than those of the other feeds. The protein ADCs of the remaining tested diets were over 80%, except for those of the MFM, DBM, and HFM diets. The DBM and HFM diets each had the lowest and second‐lowest ADCs of crude protein, lipid, and energy. In conclusion, Orange‐spotted Grouper demonstrated high nutrient digestibility for the tested animal‐based feedstuffs except MFM, DBM, FFM, and HFM. This digestibility information can aid in the formulation of feed substitutes for least cost diets to be used with cultured Orange‐spotted Grouper. [ABSTRACT FROM AUTHOR]

Highly pure and well‐dispersed yttria nanocrystalline powders were synthesized with a modified coprecipitation method that uses mixed ammonium hydroxide‐carbonate solution as the precipitant and poly acrylic acid (PAA) as the dispersant. Comparing with the yttria powders synthesized using the same route but without PAA dispersant, the PAA‐assisted powders exhibit lower level of agglomeration and better sinterability. Sintering trajectories of the powders with and without PAA dispersant were investigated. Y2O3 ceramics sintered with the PAA‐assisted powders exhibited smaller grain size, homogeneous microstructure, and higher in‐line optical transmittance. The result suggests that the polymer‐assisted coprecipitation could be used to synthesize yttria nanopowders for fabricating high optical quality transparent ceramics. [ABSTRACT FROM AUTHOR]

This work investigates the effects of doping on both the thermodynamics and kinetics of sintering in aluminum‐doped yttrium oxide nanoparticles (Al‐doped Y2O3), with the objective of delineating their interdependent effects at different stages of the process. Direct measurements of surface and grain boundary energies using differential scanning calorimetry showed that Al‐doping decreases both interfacial energies, leading to an increase in dihedral angle (from 152.7 ± 5.6° to 165.8 ± 5.5°) and, therefore, sintering stress. Densification and grain growth analyses showed that despite this increase in sintering stress, the onset of sintering is delayed for the Al‐doped samples, demonstrating that a large dihedral angle is a necessary but not sufficient condition for densification. The measurements of activation energies for densification and grain growth point out that Al suppresses grain boundary mobility by increasing the activation energy from 400 to 448 kJ/mol, hindering densification at the intermediate stages of sintering. At temperatures above 1150℃, grain growth is activated in the Al‐doped samples, which rapidly releases the accumulated sintering stress and exhibits a higher densification rate than in undoped Y2O3. This study demonstrates a complex interconnectivity between the thermodynamics and kinetics at different temperature ranges of sintering and reinforces the need for a comprehensive description for proper design of sintering aids. [ABSTRACT FROM AUTHOR]

The initial configuration of Yttrium oxide clusters (Y2O3)n (n = 1–15) was creatively constructed by combining artificial bee colony algorithm with density functional theory. The structures of large and medium‐sized yttrium oxide clusters with molecular number greater than 10 were established for the first time, and many new structures that are different from existing research have been obtained. Studies have shown that for small‐sized clusters, the atomic stacking structure is cage‐like, while for medium‐sized and large‐sized clusters, the composite trapezoidal structure and ellipsoid‐like structure are more stable. The nanoclusters tend to be stable as a whole, and the relative stability of the cluster structure is higher when n = 2, 4, 7, 9. The heat capacity (Cp), enthalpy change (H) and entropy (S) of (Y2O3)n (n = 1–15) clusters increase with the increase of temperature (T), and the vibration free energy (Gv) decreases with the increase of T. [ABSTRACT FROM AUTHOR]

Yttrium oxide (Y2O3) thin films are deposited by the third‐generation mist chemical vapor deposition (CVD) system. To avoid high growth temperature, H2O and O2, as oxygen sources, are selected to support the fabrication process. The Y2O3 films are prepared under different oxygen‐source supporting conditions to obtain high‐quality thin films; the effects of H2O and O2 on the film properties are also investigated to confirm the formation processes of Y2O3 films fabricated by mist CVD. Y2O3 films with a deposition rate of 9.0 nm min−1, refractive index of 1.76, and dielectric constant ranging from 15 to 20 are obtained at 400 °C when H2O is used to support the fabrication. Thermogravimetry–differential thermal analysis of the yttrium precursor Y(C5H7O2)3·nH2O is conducted using air and air+H2O mist as carrier gas. The analysis confirms that H2O supporting can lower the growth temperature and improve the film quality by reducing the formation temperature of main products in the process of obtaining Y2O3. Moreover, the H2O and O2 used in the fabrication are in liquid and gas phases, respectively. Consequently, the supporting processes of H2O and O2 occur at different time and space inside the reactor, which results in different supporting effects. [ABSTRACT FROM AUTHOR]

In order to get a general regularity of erosion performance in alumina‐strengthened yttria ceramics, High‐quality yttrium‐aluminum oxide composite ceramics with different alumina/yttria molar ratios were fabricated, and the as‐prepared specimens were named Y2O3, YAG, YAGA, and Al2O3. The erosion behavior of the ceramics was examined and explained. The etching morphologies of the ceramics revealed that the multi‐phase composite ceramic (YAGA) was etched selectively, whereas the single‐phase ceramics were corroded homogeneously. The weight loss rate of the ceramics after etching was not proportional to the Al2O3 content, and it conformed to the percolation theory. As the alumina content in yttrium‐aluminum oxide composite ceramics was below the minimum value of percolation transition in two‐phase system the erosion resistance of the strengthened composite ceramics demonstrated excellent as well yttria ceramics. [ABSTRACT FROM AUTHOR]

In dentistry, monolithic zirconia restorations have been preferred over all‐ceramic restorations in recent years. Translucency is an aesthetic demand in dental restorations, and it can be identified with translucency parameter (TP). Zirconia thickness, Y2O3 content, and sintering conditions are important parameters that influence the translucency of the restorations. It is crucial to investigate monolithic zirconia ceramics under different sintering regimes and reveal the critical parameters for dental restorations. The aim of this study was to determine the optical and microstructural behaviors of monolithic zirconia ceramics containing different amounts of yttria depending on various sintering regimes and thicknesses. Therefore, a conventional zirconia CopranZri (CZI) and two monolithic zirconia materials, CopraSupreme (CSP), CopraSmile (CSM) were used. Slow, normal, speed, and translucency sintering regimes with thicknesses of 0.7, 1.0, 1.3 mm were selected. TP of the specimens was calculated, and statistical analyses were performed by using one‐way ANOVA and Tukey‐Kramer post hoc tests. Characterization of the specimens was performed by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X‐ray (EDX) techniques. The results showed that the effect of different sintering programs is more critical for CSP and CSM in terms of translucency variations and translucency program led to the most grain growth. [ABSTRACT FROM AUTHOR]

The sections of control liver, kidneys, heart, brain, and spleen have been shown in Figure 2A,C,E,G, and I, respectively. The sections of control liver, kidneys, brain, spleen, and heart have been shown in Figure 2A,C,E,G, and I, respectively. A, C, E, G, and I, respectively, showing the normal architecture of liver, kidney, brain, heart, and spleen of control rats. [Extracted from the article]

Design of highly active and stable catalysts for ammonia decomposition to produce COx‐free hydrogen is an urgent task for the utilization of NH3 as H2 carrier. Herein, Yttrium oxide (Y2O3) has been demonstrated to be capable of dispersing and stabilizing Ru nanoparticles as a functional support. Highly dispersed Ru nanoparticles on Y2O3 (Ru/Y2O3) was prepared and investigated as catalyst for NH3 decomposition. Under a relatively high weight gas hourly space velocity (30000 mL gcat−1 h−1), the Ru/Y2O3 with Ru content of 5 wt. % can catalyze NH3 decomposition with excellent catalytic activity and can achieve nearly complete NH3 conversion at 475 °C, superior to many typical oxides supported Ru catalysts. The Ru/Y2O3 catalyst is also highly stable for NH3 decomposition, and the activity can be well maintained in a period of 100 hours. Characterization results reveal that the superior catalytic performance of Ru/Y2O3 for NH3 decomposition reaction may originate from the high dispersion of Ru nanoparticles as well as their strong interaction with Y2O3 support. This work offers opportunity to achieve new kind of active and stable oxide supported Ru catalysts for NH3 decomposition reaction. [ABSTRACT FROM AUTHOR]

Natural dye‐sensitized solar cells (DSSCs) are becoming promising candidates for replacing synthetic dyes. Graphene oxide is prepared from natural graphite flakes by modified Hummers method. A novel graphene oxide/yttrium oxide (GO/Y2O3) nanocomposites are prepared by chemical precipitation method. The different concentration of (5:1, 5:2, and 5:3) of yttrium oxide nanoparticles exaggerated on the surface of graphene oxide nanosheets. The prepared nanocomposites are characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), high‐resolution transmission electron microscopy (HR‐TEM), energy‐dispersive X‐ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FT‐IR), Raman scattering spectroscopy and ultraviolet–visible (UV–vis) absorption spectroscopy. The XRD analysis showed that the crystallite size of the GO/Y2O3 (5:1, 5:2, and 5:3) is found to be around 23, 25.2, and 26.92 nm. Field emission scanning electron microscopy (FE‐SEM) revealed that the flakes like shaped yttrium oxide nanoparticles are uniformly dispersed on the surface of GO sheets. The UV–vis studies showed that the prepared Jasminoum grandiflorum L (JG) dye belongs to chlorophyll group with the absorption of 4.2 eV. The electrochemical activity of the prepared nanocomposites is investigated by cyclic voltammetry (CV) technique. The power conversion efficiency of prepared sandwich type DSSCs (5:3) is found to be 1.67%. [ABSTRACT FROM AUTHOR]

Dopant segregation at grain boundaries (GBs) in ceramics has been widely reported, while whether similar segregation behavior occurs in glass‐ceramics remains unknown. The distribution of dopant in glass‐ceramics may be totally different due to the existence of glass phase. This study examines the distribution of Y3+ ions in a ZrO2‐SiO2 glass‐ceramic. Two samples were prepared by hot pressing, yttrium oxide‐doped, and undoped 65 mol% ZrO2‐35 mol% SiO2 nanocrystalline glass‐ceramics (NCGCs). The NCGCs had the same microstructure, that is, ZrO2 nanoparticles (NPs) embedded in an amorphous SiO2 matrix. XRD results showed that the undoped NCGC was composed of 20.9 wt% (weight percentage) monoclinic ZrO2 (m‐ZrO2) and 79.1 wt% tetragonal ZrO2 (t‐ZrO2), while the yttrium oxide‐doped NCGC was composed of 9.6 wt% m‐ZrO2 and 90.4 wt% t‐ZrO2. X‐ray energy‐dispersive spectrometry (EDS) results in scanning electron transmission microscopy (STEM) mode demonstrated that Y3+ ions segregated both on the surface of ZrO2 NPs and within the thin intergranular glass film (with a thickness of approximately 7 Å) between ZrO2 NPs in the yttrium oxide‐doped NCGC. Interestingly, no obvious Y signals were detected in the amorphous SiO2 matrix. Density functional theory calculation results showed that Y3+ ions had a strong segregation tendency in the GB area and the segregation of Y3+ ions increased the work of separation of GB layer. These findings provide new understanding of the segregation behavior of dopant in glass‐ceramics, which may offer useful guidance for other researchers to tailor the properties of glass‐ceramics through GB engineering. [ABSTRACT FROM AUTHOR]

Yttrium oxide (Y2O3) thin films are implemented as a functional component in a broad field of applications such as optics, electronics or thermal barrier coatings. Atomic layer deposition (ALD) is a promising technique to fabricate high‐quality thin films with atomic level precision in which the precursor choice plays a crucial role in process development. The limited number of suitable yttrium precursors available for ALD of Y2O3 has triggered increasing research activity seeking new or modified precursors. In this study, heteroleptic compounds of yttrium bearing the cyclopentadienyl (Cp) ligand in combination with the chelating amidinate or guanidinate ligands were targeted as potential precursors for ALD. In this context, a systematic and comparative study of the structure and thermal characteristics of (bis‐cyclopentadienyl‐(N,N'‐diisopropyl‐2‐methyl‐amidinato)yttrium) [YCp2(dpamd)] 1 and (bis‐cyclopentadienyl‐(N,N'‐diisopropyl‐2‐dimethylamido‐guanidinato)yttrium) [YCp2(dpdmg)] 2 was performed. Complementary characterization tools such as 1H‐NMR, elemental analysis, electron‐impact mass spectrometry (EI‐MS) and single‐crystal X‐ray diffraction (XRD) confirmed the spectroscopic purity and the monomeric nature of the metalorganic compounds. Hirshfeld surface analysis revealed influence of the ligand choice on the intermolecular interactions of the compounds. The important figures of merit for a precursor, namely the thermal properties were investigated via thermogravimetric analysis. Thus, the volatility, transport behavior and thermal stability were examined and compared to their homoleptic counterparts [YCp3], [Y(dpamd)3] or [Y(dpdmg)3]. [ABSTRACT FROM AUTHOR]

Surface energy (γS) and grain boundary energy (γGB) of yttrium oxide (Y2O3) were determined by analyzing the heat of sintering (ΔHsintering) using differential scanning calorimetry (DSC). The data allowed quantification of sintering driving forces, which when combined with a thorough kinetic analysis of the process, provide better understanding of Y2O3 densification as well as insights into effective strategies to improve its sinterability. The quantitative thermodynamic study revealed moderate thermodynamic driving force for densification in Y2O3 (as compared to other oxides) represented by a dihedral angle of 152.7° calculated from its surface and grain boundary energies. The activation energy was determined as 307 ± 61 kJ/mol, consistent with activation energies previously reported for processes relevant to sintering of Y2O3, such as Y3+ diffusion and grain boundary mobility. Finally, we propose that a refined deconvolution study on the DSC curve for Y2O3 sintering, combined with the associated material's microstructure evolution, may help identify shifts in sintering mechanisms, and therefore, specific activation energies at increasing temperatures. [ABSTRACT FROM AUTHOR]

This research focused on the identification of parasitic signal sources introduced by sintering under reductive atmospheres of oxide transparent ceramics. The examination encompassed a wide set of materials, like Mg‐spinel, magnesia, alumina. YAG, yttria, zirconia and titania, so as to allow one to detect general rules if operating. The main finding is the dependence between the ability of such ceramics to generate, under reductive conditions, intrinsic parasitic light‐absorbing centers and their composition and structure. Thus it was determined that oxides based on transition element cations have ,in this sense, abilities not present in the case of oxides of elements from the main periodic table groups. The reason is the possibility of non‐absorbing transition cations to be reduced to oxidation states that absorb light. Drive toward reduced oxidation states is motivated by the stabilization energy associated with the ligand fields acting upon the such cations. It has been also found out that YAG lattice distortion, by dopants like tetravalent silicon or zirconium facilitates reduction of Y 3+ to Y 2 + (a light absorbing, d1, cation). Oxygen vacancies do not significantly influence visible light absorption. Carbon atoms penetrate inside ceramics, even dense ones and cause achromatic tints formation. [ABSTRACT FROM AUTHOR]

Surface energy (γS) and grain boundary energy (γGB) of yttrium oxide (Y2O3) were determined by analyzing the heat of sintering (ΔHsintering) using differential scanning calorimetry (DSC). The data allowed quantification of sintering driving forces, which when combined with a thorough kinetic analysis of the process, provide better understanding of Y2O3 densification as well as insights into effective strategies to improve its sinterability. The quantitative thermodynamic study revealed moderate thermodynamic driving force for densification in Y2O3 (as compared to other oxides) represented by a dihedral angle of 152.7° calculated from its surface and grain boundary energies. The activation energy was determined as 307 ± 61 kJ/mol, consistent with activation energies previously reported for processes relevant to sintering of Y2O3, such as Y3+ diffusion and grain boundary mobility. Finally, we propose that a refined deconvolution study on the DSC curve for Y2O3 sintering, combined with the associated material's microstructure evolution, may help identify shifts in sintering mechanisms, and therefore, specific activation energies at increasing temperatures. [ABSTRACT FROM AUTHOR]

The effects of zirconia and yttrium oxide addition on microstructure, bulk density, microhardness, flexural strength, and wear resistance of high alumina ceramics (>97 wt% Al2O3, MSA ceramics) composed of MgO–SiO2–Al2O3 system have been investigated. The results show that the addition of zirconia makes the mechanical properties and wear properties of ceramics composed of MgO–SiO2–Al2O3–ZrO2 (MSAZ ceramics) system have been greatly improved compared with MSA ceramics. In addition, the ceramics composed of MgO–SiO2–Al2O3–ZrO2–Y2O3 (MSAZY ceramics) system have better mechanical properties and wear properties than MSAZ ceramics. With the contents of zirconia and yttrium oxide increase, the bulk density, microhardness, and flexural strength of MSAZ and MSAZY ceramics increased at first and then decreased. However, the wear rate shows the opposite. When 0.4 wt% ZrO2 and 0.6 wt% Y2O3 were added to the matrix, the wear rate of MSAZY ceramics reached a minimum of 0.042%, and the wear resistance was improved by about 73.8% compared with MSA ceramics with a wear rate of 0.16%. In addition, the optimum additions of zirconia and yttria are 0.4% and 0.6%, respectively. [ABSTRACT FROM AUTHOR]

The effect of direct current (DC) and alternating current (AC) on nitridation of 3 mol% Y2O3‐doped ZrO2 (3YSZ) after keeping in a flash state for 1 hour was investigated. The inside of the DC‐flashed compact was confirmed to exhibit blacking. Scanning transmission electron microscopy, electron energy loss spectroscopy, and X‐ray diffraction analysis revealed that zirconium nitrides formed in the blackened area. In contrast, a uniformly densified compact without blackening was obtained by AC fields. No zirconium nitrides formed in the compacts exposed to AC fields even when the flash state was maintained for 1 hour. Therefore, AC fields are effective to suppress nitridation of 3YSZ during flash sintering. [ABSTRACT FROM AUTHOR]

Luminescence nanothermometers are promising for noninvasive, high resolution thermographics ranging from aeronautics to biomedicine. Yet, limited success has been met in the NIR‐II/III biological windows, which allow temperature evaluation in deep tissues. Herein, a new type of phonon‐based ratiometric thermometry is described that utilizes the luminescence intensity ratio (LIR) between holmium (Ho3+) emission at ≈1190 nm (NIR‐II) and erbium (Er3+) emission at ≈1550 nm (NIR‐III) from a set of oxide nanoparticles of varying host lattices. It is shown that multi‐phonon relaxation in Er3+ ions and phonon‐assisted transfer process in Ho3+ ions play a significant role in LIR determination through channeling the harvested excitation energy to the corresponding emitting states. As a result, temperature sensitivity can be tuned by the dominant phonon energy of host lattice, thus endowing aqueous yttrium oxide (Y2O3, 376 cm−1) nanoparticles to have a relative temperature sensitivity of 1.01% K−1 and absolute temperature sensitivity of 0.0127 K−1 at 65 °C in a physiological temperature range (25–65 °C). And their temperature sensing for biological tissues is further explored and the influence of water and chicken breast on thermometry is discussed. This work constitutes a solid step forward to build sensitive NIR‐II/III nanothermometers for biological applications. [ABSTRACT FROM AUTHOR]

Al2O3‐based ceramic cores with a uniform microstructure were fabricated successfully by a traditional pressing forming method, in which Al2O3 powders were used as matrix and yttrium oxide as additive. The influences of yttrium oxide content and sintering temperature on properties of ceramic cores were studied carefully. Results indicated that a higher sintering temperature benefited the preparation of ceramic cores with excellent properties. As the temperature was above 1400°C, the reaction of Al2O3 and yttrium oxide occurred, leading to the formation of YAG phases. And, YAG was uniformly adhered on the surface of Al2O3 particles, exerting a good role in connecting Al2O3 particles. Based on XRD analyses, it was found that the increase in the sintering temperature could promote the formation of more YAG phases. When sintering temperature was adjusted to 1600°C, with the increase in the yttrium oxide content, their relative density developed a trend of decreasing first and then increasing, while the apparent porosity had an opposite change tendency. With the increase in the sintering temperature, the line shrinkage and bending strength of Al2O3‐based ceramic cores both increased gradually. In our research, their bending strength reached to 53.5 MPa and apparent porosity was 33.9% when the ceramic cores were prepared with 9 wt% yttrium oxide at 1600°C. [ABSTRACT FROM AUTHOR]

Yttrium‐doped glasses have been utilized for biomedical applications such as radiotherapy, especially for liver cancer treatment. In this paper, the crystallization behavior of phosphate‐based glasses doped with yttrium (in the system 45P2O5–(30 − x) Na2O–25CaO–xY2O3—where x = 0, 1, 3 and 5) have been investigated via Differential Scanning Calorimetry (DSC) using nonisothermal technique at different heating rates (5°C, 10°C, 15°C and 20°C/min). The glass compositions were characterized via EDX, XRD, Density and Molar volume analysis. The Moynihan and Kissinger methods were used for the determination of glass transition activation energy (Eg) which decreased from 192 to 118 kJ/mol (Moynihan) and 183 to 113 kJ/mol (Kissinger) with increasing yttrium oxide content. Incorporation of 0 to 5 mol% Y2O3 revealed an approximate decrease of 71 kJ/mol (Ozawa and Augis) for onset crystallization (Ex) and 26 kJ/mol (Kissinger) for crystallization peak activation energies (Ec). Avrami index (n) value analyzed via Matusita–Sakka equation suggested a one‐dimensional crystal growth for the glasses investigated. SEM analysis explored the crystalline morphologies and revealed one‐dimensional needle‐like crystals. Overall, it was found that these glass formulations remained amorphous with up to 5 mol% Y2O3 addition with further increases in Y2O3 content resulting in significant crystallization. [ABSTRACT FROM AUTHOR]

This study presents the fabrication and characterization of composite materials of hydroxyapatite and aluminum oxide. Hydroxyapatite powder was obtained from bovine bones via conventional calcination routine. Although hydroxyapatite shows great biocompatibility with the human body, its applications are limited to non‐load bearing areas. For this purpose, fine powders of hydroxyapatite/alumina were admixed with 1 and 5 wt.% yittria. Powder‐compacts were sintered by two‐step sintering route by increasing temperature to 1550 °C for 2 h and then sintering at 1450 °C for 4 h. The effect of increasing yittria content on sintering behavior and mechanical properties was investigated in biocomposite hybrid materials. [ABSTRACT FROM AUTHOR]

Al2O3/ZrO2(Y2O3) pseudo‐binary eutectic melt may solidify in the dendritic form at the low G/v ratio (thermal gradient G divided by growth rate v) associated with the Y2O3 microsegregation along the monovariant line. Especially, in the system with high Y2O3 content (≥4.5 mol%), an Al2O3/ZrO2/YAG ternary eutectic in situ microstructure growing with a "plane front" will appear at the boundaries of dendritic structures. The volume fraction of the ternary eutectic increases with the increase in Y2O3 content. It was found that the amount of ternary eutectic can be well predicted by the Scheil equation (or nonequilibrium lever rule). The blurb content for The graphical abstract is: Microstructure distribution characteristic of dendritic‐eutectic solidification in Al2O3/ZrO2 system doped with the high Y2O3 content, in which the formed microstructure consisting of the Al2O3/YSZ binary eutectic columnar colonies surrounded by the Al2O3/ZrO2/YAG ternary eutectic in situ microstructure. [ABSTRACT FROM AUTHOR]