Addition Of Y2O3 Research Articles

Enhancement of mechanical and physical properties of Cu–Ni composites by various contents of Y2O3 reinforcement

The increasing demand for materials possessing enhanced mechanical strength, high thermal conductivity, and excellent electrical properties has grown significantly. Cu-matrix composites, especially Cu– Ni, present a promising candidate to fulfill these demands. In this study, Cu–Ni composites were successfully synthesized using powder metallurgy with various additions (0–1.5 wt%) of Yttria (Y2O3)-reinforcement aiming to enhance their mechanical, thermal, and electrical properties. The microstructural investigations demonstrated a uniform distribution of Y2O3 particles and a slight increase in porosity of the Cu–Ni matrix. The Cu–Ni composites with 1.5 wt% Y2O3 showed the presence of Cu2NiZn intermetallic compounds, potentially harming their physical and mechanical properties. Y2O3-reinforcement significantly increased the hardness and led to a moderate rise in the yield and ultimate compressive strengths. The results indicated that the Cu–Ni matrix without Y2O3-reinforcement had the highest coefficient of thermal expansion, which decreased with the addition of Y2O3, potentially leading to improved thermal properties of Cu–Ni composites. This study puts an emphasis on the importance of Y2O3 particles dispersion and on the extent of porosity in enhancing the thermal and mechanical properties of Cu–Ni composites.

Waste to shield: Tailoring cordierite/mullite/zircon composites for radiation protection through controlled sintering and Y2O3 addition

In this study, investment casting shell waste successfully utilized to produce cordierite/mullite/zircon composites. Green pellets, consisting of investment casting shell waste, alumina, and magnesia, were prepared and sintered at temperatures between 1250 and 1350 °C. The influence of the sintering temperature on the crystalline phase composition, densification behavior, flexural strength, microstructure, and radiation shielding properties of the cordierite/mullite/zircon composites is investigated. Phase analysis showed that characteristic cordierite peaks appear at 1250 °C, but the complete conversation of silica from investment casting shell waste into cordierite requires a sintering temperature of at least 1300 °C. Notably, the cordierite/mullite/zircon composite sintered at 1350 °C exhibited a sixfold increase in flexural strength compared to the ceramic composite directly fabricated from investment casting shell waste at the same sintering temperature. Furthermore, the effect of Y2O3 addition on composites' radiation shielding properties is investigated. The results show that the Y2O3 addition improves densification behavior, enhancing the shielding capabilities of the composites against fast neutron and gamma radiation. Our findings suggest that the developed ceramic composites show significant potential for gamma-ray and neutron shielding applications.

Rapid and cost-effective fabrication of SiC from Si scrap through flash sintering

A rapid, cost-effective and eco-friendly approach for fabricating SiC using Si particles derived from Si scrap is highly recommended from both economic and environmental standpoints. Herein, we demonstrate the fabrication of β-SiC effectively in argon atmosphere at 1500°C by utilizing combustion synthesis followed by flash sintering in a single-step experiment for the first time. Synthesis of β-SiC was relied on exothermic reaction between Si and C elements present in the powder compact whereas densification was accomplished eventually through flash sintering. In addition, the effects of different flash sintering conditions on the properties of β-SiC are examined with and without Y2O3 sintering additive. A high relative density of 85% was realized when a current density of 60 mA/mm2 was applied for 60 min with Y2O3 addition. This novel one-step fabrication approach has the potential to reduce production cost of β-SiC significantly and has both commercial and environmental advantages.

Properties of Al/Y2O3 composites produced by Y2O3-Al2O3 interaction in powder metallurgy route

This study aims to improve the interfacial properties of Al/Y2O3 composites by using pre-oxidised powder. For this purpose, aluminium powder was oxidized, and composites were fabricated via vacuum hot-pressing process at 600 °C with 5 and 15 wt% Y2O3 contents, respectively. The pre-formed Al2O3 and Y2O3 reacted during the hot-pressing process, and the Y4Al2O9 phase was formed at the interface. The wear resistance and corrosion behaviour of samples were improved by the addition of Y2O3 and the formation of Y4Al2O9. Especially, the corrosion resistance of samples increased significantly, and corrosion rate of the aluminium was reduced from 0.1698 mm/year to 0.0261 mm/year by the addition of 15 % Y2O3 and formed Y4Al2O9.

Preparation and characterization of porous reaction bonded silicon nitride by paraffin emulsified suspension

Porous Si3N4 ceramics with an interconnected pore structure were prepared by a paraffin emulsified suspension method. The effects of the volume ratio of paraffin to silicon and Y2O3 addition on the structure and properties of porous Si3N4 were studied. Uniform dispersed pores introduced by the emulsified paraffine droplets can be observed in the green samples. With the increase of the volume ratio of paraffin to silicon, the bulk density and the strength of the sample were decreased, and the apparent porosity and Darcy permeability were increased. The formation of α-Si3N4 whiskers could be promoted by the addition of the Y2O3 during the nitriding process, and numerous nano whiskers could be obtained in the pores left by the paraffine droplets with suitable addition of the Y2O3. The porous Si3N4 with interconnected whiskers prepared via the paraffin emulsion method exhibited potential application for hot gas particular matter filtration.

Effect of Y2O3 Concentration on the Surface and Bulk Crystallization of Multicomponent Silicate Glasses

Multicomponent silicate glasses are crystallized by Y2O3 addition. Depending on the Y2O3 concentration, different crystalline phases evolve. In the absence of Y2O3, a multicomponent glass crystallizes as ZnSnO3, while with the addition of just 3% of this oxide, ZnSnO3 no longer crystallizes and ZrSiO4 appears instead. Different yttrium silicate crystals are formed in all glasses containing Y2O3, but, while α-Y2Si2O7 and β-Y2Si2O7 are favored at low Y2O3 concentrations, the γ-Y2Si2O7 and y-Y2Si2O7 phases are favored at the maximum Y2O3 content. At a 12% Y2O3 concentration, barium and calcium silicate crystalline phases also evolve. Interestingly, the crystalline phases appearing on the surface of the material present different microstructures compared to crystals developed in the bulk. While the crystallized surface presents a tabular-shape type, crystallization in the bulk is of a prismatic type at low Y2O3 concentrations and of a globular (spherical) type at higher concentrations. The main crystal size ranges between 0.85 and 0.75 micrometers, but most of the crystals coalesce to form larger superstructures depending on the Y2O3 concentrations.

Influence of Grain-Growth Inhibitors on Modified (Ba,Sr)(Sn,Ti)O3 for Electrocaloric Application.

The paper reports on effect of grain-growth inhibitors MgO, Y2O3 and MnCO3 as well as Ca modification on the microstructure, dielectric, ferroelectric and electrocaloric (EC) properties of Ba0.82Sr0.18Sn0.065Ti0.935O3 (BSSnT). Furthermore, the effects of the sintering time and temperature on the microstructure and the electrical properties of the most promising material system Ba0.62Ca0.20Sr0.18Sn0.065Ti0.935O3 (BCSSnT-20) are investigated. Additions of MgO (xMgO = 1%), Y2O3 (xY2O3 = 0.25%) and MnCO3 (xMnCO3 = 1%) significantly decreased the mean grain size of BSSnT to 0.4 µm, 0.8 µm and 0.4 µm, respectively. Ba0.62Ca0.20Sr0.18Sn0.065Ti0.935O3 (BCSSnT-20) gained a homogeneous fine-grained microstructure with an average grain size of 1.5 µm, leading to a maximum electrocaloric temperature change |ΔTEC| of 0.49 K at 40 °C with a broad peak of |ΔTEC| > 0.33 K in the temperature range from 10 °C to 75 °C under an electric field change of 5 V µm-1. By increasing the sintering temperature of BCSSnT-20 from 1350 °C to 1425 °C, the grain size increased from 1.5 µm to 7.3 µm and the maximum electrocaloric temperature change |ΔTEC| increased from 0.15 K at 35 °C to 0.37 K at 20 °C under an electric field change of 2 V µm-1. Our results show that under all investigated material systems, BCSSnT-20 is the most promising candidate for future application in multilayer ceramic (MLC) components for EC cooling devices.

Effect of Y2O3 addition on the organization and tribological properties of Ni60A/Cr3C2 composite coatings obtained by laser-cladding

This study aims to enhance the surface toughness and overall performance of arc-shaped nail teeth, which are vital components of presowing film-recovery machinery. Laser cladding technology was employed to deposit Ni60A/Cr3C2 composite coatings with the rare-earth oxide Y2O3 onto 60Si2Mn steel surfaces. The effects of different amounts of Y2O3 on the wear resistance of Ni60A/Cr3C2 composite coatings were evaluated. Scanning electron microscopy (SEM), X-ray diffraction, X-ray photoelectron spectroscopy, and 3D morphological analysis were used to investigate the microstructure, microhardness, elemental distribution, and tribological properties of the coatings. The ideal amount of Y2O3 to add to the mixtures to enhance the wear resistance was determined. The results showed that the coating containing 1.5% Y2O3 and Ni60A/Cr3C2 composite powder exhibited superior overall performance. Coatings with different amounts of added Y2O3 exhibited similar phase compositions, mainly consisting of γ-Ni-based, Ni2Si, M7C3 (M = Cr, Mn), and M23C6-strengthened phases. SEM analysis revealed that the coating with 1.5% Y2O3 exhibited excellent metallurgical bonding with the substrate. In addition, the coating exhibited finer grains, increased density, a more uniform distribution of coating elements, and a microhardness of 990 HV. Fewer grooves and smoother abrasions were observed after the wear test. The wear amount and depth were 14 × 10−4 g and 8.97 μm, which were 22.2% and 55.4% lower than the coating without added Y2O3, respectively. The tribological behavior indicated that adding the appropriate amount of Y2O3 facilitated the grain boundary consolidation while enhancing the adhesive properties of the oxide film, thereby increasing the wear resistance of the coating.

Regulating the pore structure of periclase refractories by adding Y2O3 to enhance corrosion resistance for copper slag

AbstractThe penetration of copper‐smelting slag into refractories is a major challenge to the research of chromium‐free refractories for copper‐smelting furnace. In this paper, Y2O3 was added to regulate the pore structure of periclase refractories, which enhanced their various properties, especially corrosion resistance to copper converter slag. The results showed that the periclase refractories doped with 1.0 wt.% Y2O3 (1Y sample) possessed the optimum properties. Compared to the sample without Y2O3, the apparent porosity of 1Y sample was decreased by 7.3%, and its average pore diameter was only 3.7 μm. The addition of Y2O3 filled the pores among MgO grains and promoted the expansion of high melting point silicates, thereby reducing the pore size and causing more complex pore structures. This was beneficial to improving the corrosion resistance of periclase to copper slag, especially to prevent the penetration of Cux+ and Na+. After static slag corrosion, the permeability index was significantly decreased by 41% compared to periclase refractories without Y2O3. Moreover, compared to industrial MgO–Cr2O3 refractories, the 1Y sample possessed better resistance to copper slag erosion based on rotating finger tests, and its permeability index and penetration depth decreased by almost 50%.

Cu/ZrO2 Catalyst Modified with Y2O3 for Effective and Stable Dehydration of Glycerol to Acetol.

Glycerol is a main by-product of biodiesel production, and its further processing is essential for the biorefinery. In this paper, a highly active and stable catalyst for the catalytic dehydration of glycerol to acetol is obtained by modifying a Cu-Zr (ZrO2 supported Cu) catalyst with Y2O3 using a co-precipitation method. It is found that the addition of Y2O3 effectively enhances the catalytic performance of Cu-Zr. Cu-Zr reaches the highest selectivity (82.4%) to acetol at 24 h. However, the selectivity decreases to 70.1% at 36 h. The conversion also decreases from 99.2 to 91.1%. Cu-Zr-Y exhibits very high activity and very good stability. During a 250 h reaction, no deactivation is observed, and the conversion and selectivity remains ~100% and ~85%, respectively. The catalysts are characterized by XRD, TEM, H2-TPR, and NH3-TPD. The results reveal that Y2O3 not only improves the dispersion of Cu and the acidity of the catalyst but also restrains the agglomeration of Cu particles and assists retaining the main structure of support under reaction conditions. The high dispersion, high acidity content, and stable structure contributes to the excellent catalytic performance of Cu-Zr-Y.

Investigation on different additions as candidates for nano-oxide particles in nickel-based ODS superalloys

Four nickel-based oxide dispersion strengthened (ODS) superalloys with the additions of YH2, Y2O3, La2O3 and CeO2 (denoted as ODS-Y1 ODS-Y2, ODS-La and ODS-Ce) are prepared, respectively. The tensile tests at temperatures ranging from room temperature (RT) to 1000 °C were conducted on them. In this work, by means of microstructure characterization and theoretical modeling, different strengthening mechanisms including grain boundary strengthening, solution strengthening, dislocations and dispersion strengthening, were estimated to contribute to the yield strength in different degrees, which would help to further enhance the tensile properties of alloys through nanoparticles optimization thereafter, and the formation and evolution mechanism of nanoparticles are discussed. The results show that ODS-Y1 has the smallest particles and the best comprehensive mechanical property in the tested alloys. The nanoparticles having M-Al-rich (M = Y, La, Ce) cores and Ti-O-rich shells structure are observed in nickel-based ODS superalloys, and the M-Al-O are preferentially formed, due to the higher diffusion rate of Al atom and high M/Al value. Then Ti and O atoms diffuse to the surface of nanoparticles, forming a core-shell structures in the later precipitation stages.

Synthesis of Y2O3 and graphite-added copper-based hybrid composites by powder metallurgy: Mechanical properties and tribological behavior

In the presented study, Y2O3 and graphite-reinforced Cu matrix hybrid composite materials were prepared using the powder metallurgy method. The aim is to compare the microstructure, density, hardness, and wear behavior of composites with different yttria contents (5, 10, and 15 weight%) and graphite (2 weight%) reinforcements. An increase in the Y2O3 ratio, along with the addition of graphite, resulted in an observed increase in the hardness values of the composites. Additionally, it was observed that Y2O3 and graphite are homogeneously distributed in the copper matrix in the SEM-EDX spectra. Upon examining the microstructures of the composites, it was determined that with the increase in yttrium oxide content, partially yttrium oxide agglomerations formed in some regions. The addition of Y2O3 resulted in a copper sample that is 1,34 times harder than pure copper. Addition of Y2O3 -graphite, samples with 3.301-22.3 % higher wear resistance were obtained.

Deciphering the effect of grain boundary characteristics on fracture toughness of silicon nitride ceramics through a CNN regression model

Fracture toughness of silicon nitride (Si3N4) ceramics with different grain boundary characteristics was determined from their microstructural images via a convolutional neural network (CNN) model. For this purpose, the CNN model was trained using Si3N4 ceramics with sintering additives of Y2O3 and MgO, and then the fracture toughness for those with various lanthanoid oxides and MgO was determined from the microstructural images through the trained model. Herein, the difference between the determined and measured values indicates the effect of the grain boundary characteristics because they little appear in the microstructures. The measured and AI-determined fracture toughness showed that the large ionic radius of Sm2O3 enhanced the fracture toughness of the Si3N4 ceramics sintered at 1850 °C for 24 h. The trained model successfully determined fracture toughness values that closely matched the measured ones from the microstructural images, even for samples with pores and different grain boundary characteristics, except for the Sm2O3 sample sintered for 24 h.

Equiaxed colony growth in the small undercooled Y2O3-doped Al2O3–ZrO2 eutectic ceramic melt

Al2O3/ZrO2 eutectic bulks (20 mm in diameter) with different Y2O3 contents (0–4.5 mol %) were grown using the conventional casting method. Variations in the microstructural characteristics and colony tip growth behavior caused by Y2O3 addition in the central equiaxed grain zone were investigated. As Y2O3 was added to the Al2O3/ZrO2 binary eutectic, except for a decrease in colony size, the colony tip radius reduced drastically and then increased slightly. Colony growth behavior can be well predicted using the Lipton–Glicksman–Kurz (LGK) model. A critical Y2O3 content (0.5–1.1 mol%) exists below which the eutectic colony growth is accelerated owing to the Y2O3 addition, but slowed down otherwise. However, the average interphase spacing and ZrO2 rod diameter inside the colonies varied with Y2O3 content, converse to the growth rate.

The effect of Y2O3 nanoparticle addition on the microstructure and high-temperature corrosion resistance of IN718 deposited by extreme high-speed laser cladding

The microstructural evolution and 700 °C high temperature corrosion resistance of Y2O3/IN718 composite coatings with different Y2O3 contents (0, 0.5, 1.0, 1.5, 2.0, and 3.0 wt%) fabricated by extreme high-speed laser cladding (EHLC) were investigated. The results showed that the addition of 1.0 wt% Y2O3 nanoparticles to IN718 could effectively reduce the internal porosity of the specimen, reduce crack initiation, refine the grain size, and improve the high-temperature corrosion resistance. The roughness Ra was reduced by 25.9 %, from 23.93 μm to 17.73 μm, and the average grain size was reduced by 39.5 %, from 47.32 μm to 28.62 μm. The result is due to the reduction in surface roughness and porosity of the specimen after the addition of Y2O3, which forms new nucleation sites at grain boundaries, resulting in surrounding lattice distortion and grain refinement.

Fast densification mechanism of highly transparent AlON ceramics pressureless sintered by co-doping Y2O3 and MgO additives

By co-doping 0.15 wt% Y2O3 and 0.60 wt% MgO, AlON ceramics with high transmittance in visible and infrared range (the maximum transmittance of 81.8%@3600 nm, 78.1%@400 nm) were successfully fast fabricated via pressureless sintering at 1880 °C for 2.5 h. The phase assemblage, microstructure and densification process of samples doped (Y2O3/MgO single- and co-doped) and undoped additives during heating were monitored to explore the densification mechanism. MgO was found to be an exceptional inhibitor for both AlON decomposition and grain growth. By incorporating MgO as one constituent of additives, the content of α-Al2O3 that decomposed from AlON in samples during heating was significantly reduced and Mg2+ illustrated inhibition to grain boundary migration, resulting in particle aggregation/coarsening were effectively suppressed at ≤ 1600 °C. Based on the obtained microstructure with compacted small particles and negligible particle aggregation/coarsening at early stage of sintering, facilitated by the acceleration of Y3+ on mass transfer, rapid densification of AlON was achieved.

Effect of Y2O3 content on the microstructure and wear performance of plasma-sprayed Cr2O3–Y2O3 composite coatings

As the inner working surface of a diesel engine, the cylinder liner is subjected to a harsh frictional wear environment, which can lead to performance degradation and ultimately affect the engine's service life. Ceramic coatings can improve the wear resistance of the cylinder liner, thereby enhancing the reliability and stability of the diesel engine. In this study, Cr2O3–Y2O3 ceramic composite coatings were deposited on the substrate of 304 stainless steel by atmospheric plasma spraying (APS). The influence of Y2O3 content on the microstructure, porosity, phase composition, microhardness and wear performance of the composite coating was investigated. The results showed that the composite coatings exhibited a typical layered structure, and Y2O3 and Cr2O3 were dispersed relatively evenly. When the Y2O3 content was 10 %, the coating had the lowest porosity rate of 5.41 % and the highest hardness of 1094.6 HV1. As the Y2O3 content increased, the coating exhibited an increase in porosity and a decrease in hardness. Under dry friction conditions, the friction coefficient curve underwent a rapid increase phase, followed by stabilizing within the range of 0.29–0.40. When the Y2O3 content is 10 %, the coating exhibits the best wear resistance, including the lowest coefficient of friction, wear rate, and scratch depth. However, the composite exhibits the worst wear resistance when the Y2O3 content reaches 50 %. The wear mechanism was altered by the addition of Y2O3. At lower Y2O3 content, the predominant wear mechanism was abrasive wear resulting from particle refinement. Conversely, at higher content, adhesive wear caused by wear transfer from the milling balls became more prominent.

Nano-Y2O3 effects on the electrical contact properties of Al2O3-Cu/35Cr3TiB2 composites

Al2O3-Cu/35Cr3TiB2 and 0.5Y2O3/Al2O3-Cu/35Cr3TiB2 electrical contact composites were prepared by vacuum hot pressing sintering endo-oxidation method. Both composites were over 98% dense with tensile strengths of 395 MPa and 413 MPa and compressive strengths of 839 MPa and 898 MPa, respectively. The TEM results showed that Cr and TiB2 particles along with Al2O3 nanoparticles generated by internal oxidation were uniformly distributed in the Cu matrix. The addition of Y2O3 had almost no negative effects on the electrical conductivity and hardness of the composites. The electrical contact parameters such as arc energy, arc duration, and weld force between pairs of contacts were analyzed. The material transfer direction of both composite contacts was from cathode to anode. The average welding force of the contacts decreased by 24.6% after the addition of Y2O3, and the material transfer and loss decreased by 28.6% and 42% at 35 A current, respectively. The addition of Y2O3 reduced the arc energy and duration by 43.7% and 55.9% at 25 A and 35 A, respectively, and improved the stability of the contacts during disconnect and closure.

Improvement of electrical performance of ZnO linear resistors by Y2O3 doping

ZnO-TiO2−MgO-Al2O3 linear resistors with various Y2O3 dopant concentrations were fabricated using the conventional solid-state reaction method. The comprehensive investigation of the impact of Y2O3 addition on the microstructure and electrical characteristics of the resistors was carried out. The results indicated that the Y2O3 phase hindered the growth of zinc oxide particles. Additionally, the incorporation of yttrium oxide increased the linearity of the resistors and affected the height of the grain boundary barrier (φb). Subsequently, a Y2O3-doped ZnO linear resistor with a nonlinearity constant (α) of 1.09 and a resistance-temperature constant (αT) of -2.51 × 10−3/ °C was effectively produced. The comprehensive evaluation of the microstructure and relevant electrical characteristics enables the efficient production of linear resistors with excellent electrical properties.

Study of microstructure, thermodynamic and powder properties of nano Y2O3, TiO2, ZrO2 dispersed W–Ni–Nb–Mo–Zr alloys

The paper reports the synthesis of 1 wt% nano Y2O3 (Sa), TiO2 (Sb), ZrO2 (Sc) separately dispersed in W78Ni10Nb5Mo5Zr1 (in wt. %) alloys by mechanical alloying. X-ray diffraction (XRD) analysis shows that Zr with Y2O3 addition has maximum refinement in crystallite size (9.23 nm) and enhancement in lattice strain. High-resolution Transmission electron microscopy (HRTEM) and Selected area diffraction (SAD) studies indicate the development of nanocrystallites at 20 h of milling of oxide dispersion strengthened (ODS) W alloys. Thermodynamic analysis shows marginally negative enthalpy of mixing of W–Ni–Nb–Mo–Zr alloy. The XRD data and thermodynamic analysis reveal that Ni, Mo, Nb, Zr can form solid solutions with W. The average particle size measured from Dynamic Light Scattering is minimum for alloy Sa (0.9 ± 0.02 μm). The Carr's index, Hausner ratio, and angle of repose (AOR) value suggest that alloy Sa shows excellent flowability and is significant to achieve enhanced die filling and consolidation of powders.