Effect Of ZrO2 Research Articles

The effect of ZrO2 on the structure, properties and crystallization behavior of transparent lithium disilicate based glass-ceramics

The effects of ZrO2 on the parent glass network structure, crystallization behavior, and properties of lithium aluminosilicate glass-ceramics by various amounts of ZrO2 were investigated. The main crystalline phases of transparent glass-ceramics are quartz solid solution and Li2Si2O5. The increase of ZrO2 addition promotes an increasing of Q3(Zr) tetrahedral proportion in the glass network, resulting a reduction of ZrO2 nucleus. The increase of ZrO2 content also effectively improves the fracture toughness of glass-ceramics, but reduces the transmittance significantly. In this work, the glass with the 1 mol% ZrO2 nucleated at 545 °C for 2 h and crystallized at 800 °C for 2h possesses the excellent comprehensive properties, which exhibited the Vickers hardness of 6.91 GPa, the fracture toughness of ∼1.40 MPa·m1/2, and the transmittance at 550 nm of 90 %. It provides significant potential applications in the display protective cover.

Regulating the microenvironments and the d-band center of hierarchical NiMoS/TS-1 catalyst by ZrO2 to enhance the hydrodesulfurization performance of dibenzothiophene

The microenvironments including the surface hydroxyls, the oxygen vacancies, and the d-band center of hierarchical TS-1 zeolite pickled by hydrochloric acid were regulated by ZrO2, the effect of ZrO2 on the physicochemical properties and the catalytic performances of the corresponding NiMoS supported catalysts were studied. The experimental and theoretical calculation results show that the d-band center, the surface hydroxyl groups, and the oxygen vacancies were regulated after incorporation of ZrO2. Resulting in the modulated acidity of the support and the metal support interaction of the catalysts, further promoting the formation of type-II NiMoS active phases. The catalytic performance evaluations show that catalyst NiMo/1-ZAT exhibits the superior HDS performance, kinetic study further demonstrated that the enhanced catalytic activity was mainly contributed by the improved direct desulfurization activity generated from the moderate support acidity, suitable MSI, highest sulfidation degrees, most type-II NiMoS active phase and highest activity of individual active sites.

Effect of ZrO2 on Radiation Permeability Properties of Polypropylene

The study investigates the radiation permeability properties including mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), tenth value layer (TVL), half value layer (HVL), fast neutron cross section (FNRC), and mean free path (MFP) of polypropylene (PP) polymer, as well as the produced polymer matrix composites (PP+5% ZrO2, PP+10% ZrO2, PP+15% ZrO2). The studied materials were examined by considering their effect on radiation permeability against gamma and neutron radiation. Additionally, powder size, Archimedes principle (density), XRD, DSC, ATR, and DTA-TG analyses were performed. According to the radiation permeability results of the studied four materials, PP + 15% ZrO2 was found to have the highest LAC values, while PP was found to have the lowest LAC values. The FNRC values of the PP, PP+5% ZrO2, PP+10% ZrO2, and PP+15% ZrO2 materials were found to be 10.038 cm-1, 12.651 cm-1, 15.002 cm-1, and 17.091 cm-1, respectively. The most suitable material for gamma and neutron shielding was found to be 15% ZrO2 reinforced material.

Effects of ZrO2 and ZnO nanoparticles on electromagnetic interference shielding effectiveness of PA6 ultrathin hybrid nanomembranes

Electromagnetic interference (EMI) shielding materials for wearable applications should be flexible and thin. Ultrathin, flexible, polymer-ceramic hybrid nanomembranes (HNMs) were synthesized by the electrospinning method. The effects of the incorporation of zirconium oxide ZrO2 and zinc oxide ZnO nanoparticles (NPs) within polyamid6 (PA6) fibers on the EMI shielding performance were evaluated. The ZrO2 NPs changed the morphology of the fibers, whereas, ZnO intensified the crystallinity of PA6. Both additives enhanced the dielectric constant of the PA6 membrane. The results showed that the portion of the reflection was not changed, but the portion of the absorption of electromagnetic waves (EM) was increased by incorporating additives. An EMI shielding of 5.8 dB was achieved at a frequency of 4.8 GHz by an ultrathin PA6-ZrO2 HNM with a thickness of 50 ± 10 μm. Findings highly suggest HNMs for wearable EMI shielding in 5th generation mobilenetwork (5G) technology.

Effect of ZrO2 on the phase relations for CaO-SiO2-TiO2 system related to efficient extraction of titanium from titania-bearing slag

The selective crystallization and phase separation process has been regarded as a promising process for the recycling of titanium from titania-bearing furnace slag, however, the composition modification mechanism still remains unclear due to the lack of fundamental thermodynamic data. In the present work, the influence of ZrO2 addition on the equilibrium phase relations and the 1400 °C isotherm for CaO-SiO2-TiO2 system were experimentally determined by using the high temperature equilibration-quenching technique, and Scanning Electron Microscopy-Energy Dispersive X-ray Spectrometry, and X-ray diffraction analysis. The equilibrium solid phases of rutile (TiO2), perovskite (CaTiO3), and tridymite (SiO2) are determined to be coexisting with the liquid phase. In addition, comparisons of present results with thermodynamic calculation by FactSage show significant discrepancies. The present work is important for enriching the thermodynamic database of titania-bearing slag oxide systems as well as optimizing the selective crystallization and phase separation process.

Effect of ZrO2 on physical and radiation shielding properties of tellurium −lead- calcium −borate (TPCB)glass system

This research investigates the impact of adding Zirconia (ZrO2) to tellurium-lead-borate glasses, focusing on how it affects their physical, optical, and radiation shielding properties, particularly against gamma-rays and neutrons. Key parameters for gamma-ray shielding (mass attenuation coefficient (µm), effective atomic numbers (Zeff), and effective electron densities (Neff)) were measured across an energy range of 0.080 to 2.614 MeV. Notably, excellent agreement (within 0.5 %) was observed between the measured and calculated µm values. For slow neutron attenuation measurements, we employed a 241Am-Be neutron source in conjunction with a BF3 detector. Fast neutron attenuation was assessed using the NXCOM software to determine the effective macroscopic removal cross-section (ΣR). The addition of Zirconia notably enhanced the glass density (∼6.8 %) and its ability to shield against gamma-rays (∼10 %) and slow neutrons (∼71 %). However, this improvement comes with a slight trade-off: a decrease of approximately 1.5 % in fast neutron attenuation was observed. This trade-off between shielding effectiveness for different radiation types warrants further investigation to optimize glass compositions, considering the desired balance between shielding performance across various radiation spectrums.

Enhancing longevity and performance: The effects of ZrO2 and TaC coatings on pistons in internal combustion engines

Coating of pistons with ZrO2 and TaC improves their longevity and performance in internal combustion engines by enhancing the resistance to wear, heat and corrosion. In this study the plasma spray coating is performed on crown of the piston with the combination of the percentage composition namely, 95 % ZrO2 + 5 % TaC, 98 % ZrO2 + 2 % TaC and 100 % ZrO2. Among the three 95 % ZrO2 + 5 % TaC composition shows better results. The increase in ZrO2 content leads to the formation of a more integrated scale with fewer pores. Higher concentrations of ZrO2 in the coatings lead to the increased interaction with discharge sparks and instability of the process. At elevated temperatures, a two-phase material of cubic zirconium dioxide and hexagonal corundum was formed. The bonding strength of the coating is influenced by the addition of TaC and the power input during the spraying operation. The microstructure of ZrO2 and TaC coatings on aluminium alloy is characterized by granular structure, tightly packed pores and partially melted ZrO2 particles. The coating had a uniform structure with columnar and cluster-like elements, influenced by ZrO2 concentration.

Effect of nucleating agent additions on gahnite based glass-ceramic glazes

The effect of ZrO2 and TiO2 addition in gahnite-based glass-ceramic glazes was investigated by equimolar nucleating agents substituting 5 mol% SiO2. The effect of this substitution on thermal behavior was studied by means of differential thermal analysis and hot stage microscopy. The sintering behavior of samples changed with the type of nucleating agent added. Compacted samples sintered between 850 and 1200 °C for 2 min at 40°Cmin−1 heating and cooling rate for determining the crystallization sequence with using X-ray diffraction. Prepared glaze samples fired at 1180 °C for 6 min in the industrial roller kiln. Total firing time is 58 min from cold to cold. The effect of nucleating agent additions of gahnite-based glass-ceramic glazes was investigated by X-ray diffraction, scanning electron microscopy, spectrophotometer, and gloss meter. Glaze without nucleating agents shows heterogeneous surface crystallization from the frit surface to the inside with dendritic gahnite growth. With the nucleating agent, volume crystallization was seen with phase separation or seeding effect, which depends on the type of nucleating agent. Glaze with TiO2 has two different morphology; one region has fine gahnite crystals below 100 nm, and another region has clusters of nano gahnite crystals in flake-like morphology. ZrO2 provides fine gahnite crystallization, which is smaller than 80 nm. While ZrO2 added glaze is translucent, the other glazes are opaque due to different crystal sizes. It is observed that nano crystallization has a positive effect on pore swelling behavior due to its high crystal surface area. With the addition of the ZrO2 and TiO2, fine-sized nanocrystalline gahnite based glass-ceramic glazes can be obtained for the first time in industrial fast-firing conditions.

Synthesis and characterization of sodium-aluminophosphate based glass-ceramics containing NZP phase for HLW immobilization

Stable sodium-aluminophosphate (SAP) based glass-ceramics with sodium zirconium phosphate (NZP) crystalline phase for high-level nuclear waste (HLW) immobilization were prepared by a melt-quenching process, and the effects of ZrO2 and B2O3 on their phase composition, structural features and properties were discussed in detail. The results show that the SAP based glass-ceramics obtained by the melt-quenching process show good aqueous durability and thermal stability. ZrO2 addition improves the formation of NZP phase but restrains the crystallization of AlPO4 phases. It is found that the correct ratios of ZrO2 and B2O3 allow only phase formation of NZP within the SAP glass, and the reasons were also analyzed. The conclusions demonstrate that the SAP based glass-ceramics with NZP phase as the crystalline phase are the potential matrices for specific HLW immobilization, and suggest that the melt-quenching process is an applicable way to prepare certain glass-ceramic waste forms.

Effect of ZrO2 and TiO2 on the micro-structure and NIR luminescence of mullite type Cr:Al4B2O9 glass ceramics

Boron-mullites are potential candidate crystal phases for broadband near-infrared (NIR) luminescence in the mullite series due to their higher complexity in crystal structure and abundant [AlO6] units for accommodating transition metal ions as luminescence activators. In this work, the effect of ZrO2 and TiO2 on the microstructure and NIR luminescent properties of mullite type Cr3+:Al4B2O9 glass ceramics were analyzed in detail. Through characterizations including XRD, SEM, TEM and NMR, the oriented growth of strip-shaped grains in ZrO2 doped glass ceramic samples has been verified. The proportion of [AlO6] units is strongly correlated with NIR spectra, suggesting that the strategy for modulation the NIR luminescence through oriented growth can be generalized as a universal method for manipulation of the optical properties for transition metal ion activated crystals with the mullite type structure.

The origin of microstructural inhomogeneity in vacuum‐sintered ZrO2‐doped Lu2O3 transparent ceramics

AbstractHighly transparent Lu2O3 ceramics were prepared by using co‐precipitation combined with vacuum sintering method with ZrO2 as sintering aid. The effect of ZrO2 on densification, transmittance, and microstructure evolution of the Lu2O3 ceramics was carefully studied. It was found that the addition of ZrO2 was very effective in improving densification of Lu2O3. The highest transmittance (at 600 nm) of the 3 at.% ZrO2 doped Lu2O3 ceramic (1.6‐mm thickness) sintered at 1800°C reached 80.1%. Microstructural inhomogeneity was found after vacuum sintering with larger grain sizes at the central. The microstructural inhomogeneity mainly occurred in the final stage of sintering. Doping ZrO2 mitigated microstructural inhomogeneity and decreased markedly the grain size of Lu2O3 ceramics. Raman measurements indicated that the disordered structure was formed due to oxygen vacancy, and the oxygen vacancy concentration at the central was higher than at the peripheral. The oxygen vacancy concentration gradient is the dominant factor governing nonuniform microstructure evolution during vacuum sintering. Furthermore, a uniform microstructure was obtained by the inhibition of oxygen vacancy formation by the Lu2O3/ZrO2 double powder bed.

Effect of ZrO2/CeO2 mixed oxides on fuel gas production during self-sustaining smouldering combustion of lignocellulosic wastes

This study investigates the catalytic effects of ZrO2/CeO2 mixed oxides on product gases produced via self-sustaining smouldering combustion of lignocellulosic biomass.

Demonstration of ferroelectricity in PLD grown HfO<sub>2</sub>-ZrO<sub>2</sub> nanolaminates

<abstract> <p>Ferroelectricity is demonstrated for the first time in Si(100)/SiO<sub>2</sub>/TiN/HfO<sub>2</sub>-ZrO<sub>2</sub>/TiN stack using pulsed laser deposition (PLD) and the effects of temperatures, partial oxygen pressures, and thickness for the stabilization of the ferroelectric phase were mapped. Thin films deposited at a higher temperature and a higher oxygen partial pressure have a higher thickness, demonstrating a better ferroelectric response with ~12 μC/cm<sup>2</sup> remnant polarization, a leakage current of 10<sup>−7</sup> A (at 8 V) and endurance > 10<sup>11</sup> cycles indicative of an orthorhombic crystal phase. In contrast, thin films deposited at lower temperatures and pressures does not exhibit ferroelectric behavior. These films can be attributed to having a dominant monoclinic phase, having lower grain size and increased leakage current. Finally, the effects of ZrO<sub>2</sub> as top and bottom layer were also investigated which showed that ZrO<sub>2</sub> as the top layer provided better mechanical confinement for stabilizing the orthorhombic phase instead of as the bottom layer.</p> </abstract>

Preparation and interfacial bonding of oversize ZrO2 reinforced metal matrix composites prepared by spark plasma sintering

• Process of preparing large-size ZrO 2 particle reinforced composites was explored. • The suitable electroless Ni-plating process of ZrO 2 surface was given. • Effect of ZrO 2 reinforcement on the relative current distribution was revealed. • Ni-plating on ZrO 2 surface promote the interface bonding during sintering. Spark plasma sintering (SPS) is often used to prepare metal-based ceramic composites, which can keep the plasticity of metal, as well as special physical and chemical properties of ceramics. The content and particle size of ceramic reinforced phase directly determine the physical and chemical properties of composite materials. Though the reinforced phase of rigid ceramics will hinder the densification of composites and seriously lead to interface nonbonding. In this work, it’s observed that composite with oversize ZrO 2 reinforced phase hinder heterogeneous interface bonding by changing the current path. Herein, we propose Ni-plating ZrO 2 particles to promote the formation of sintering neck between metal matrix and ZrO 2 particles and improve the wettability of ceramic surface. The ZrO 2 ceramic particle reinforced composite with high density was obtained. The process also has referential significance for enhancing mechanical properties of micro/nano ceramic reinforced composites.

Micromechanical properties of hydroxyapatite nanocomposites reinforced with CNTs and ZrO2

This study examined the mechanical properties, wettability, and tribology of hydroxyapatite (HA)–zirconia (ZrO2)–carbon nanotube (CNTs) ceramic nanocomposites (with various CNT ratios (x): 1, 5, and 10 wt%). HA–ZrO2–CNT-x powders were hydrothermally synthesized. Hot isostatic pressing (HIP) and cold isostatic pressing were used to manufacture solid and dense tablets; consolidation was performed by sintering the nanocomposites under Ar gas at 1150 °C during HIP. The microstructure and morphology of the nanocomposites were characterized via transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffractometry, Fourier transform infrared (FTIR), and scanning electron microscopy. The effects of ZrO2 and CNTs on the mechanical characteristics of the nanocomposites were examined via nanoindentation, reciprocating wear, and Vickers hardness tests. The microhardness of HA–ZrO2–CNT-1% and HA–ZrO2–CNT-5% increased by 36.8% and 66.67%, respectively, compared with that of pure HA. The nanohardness of the HA–ZrO2–CNT-1%, HA–ZrO2–CNT-5%, and HA–ZrO2–CNT-10% samples was 8.3, 9.65, and 8.02 Gpa, and the corresponding elastic modulus was 83.72, 114.34, and 89.27 GPa, respectively. Both of these parameters were higher than those of pure HA. However, in the nanocomposite reinforced with 10% CNT, as opposed to those with lower CNT ratios, their values were lower. Additionally, HA–ZrO2–CNT-10% was the most hydrophilic nanocomposite synthesized in this study with a contact angle of 48.8°.

Compositional optimization of high-solid-loading ceramic cores via 3D printing

In this study, the effects of ZrO 2 mineralizer on the curing behavior of a silica-based core slurry and the microstructure and properties of the core were analyzed to optimize the properties of the samples. The results show that ZrO 2 addition aggravates the light scattering effect during the curing process, which increases the mis-cured region. However, ZrO 2 readily reacts with the fused silica glass in the matrix to form ZrSiO 4 , which inhibits the initiation and propagation of cracks and improves the high-temperature mechanical properties of the 60 vol% high-solid-loading core slurry. The content of ZrO 2 mineralizer in the slurry should be controlled within the range of 2.0–2.5 vol% for optimal mechanical performance.

Highly active Pt/In2O3-ZrO2 catalyst for CO2 hydrogenation to methanol with enhanced CO tolerance: The effects of ZrO2

The supported Pt catalyst is normally not active for CO2 hydrogenation to methanol at the presence of CO. Herein, ZrO2 is added into Pt/In2O3 for CO2 hydrogenation to methanol with CO as a co-feed gas. High activity with enhanced CO tolerance is achieved on Pt/In2O3-ZrO2. For example, the space-time yield of methanol reaches 0.569 gmethanol gcat−1 h−1 at 300 °C and 5 MPa under feed gas containing 4% CO of 21,000 cm3·h−1·gcat−1. With the addition of ZrO2, a stronger electron transfer occurs between Pt and the In2O3-ZrO2 solid solution support. This leads to weaker CO adsorption, which suppresses over-reduction of In2O3 and enhances CO tolerance of the Pt catalyst. The oxygen vacancy of In2O3 modified by ZrO2 promotes CO2 activation. The synergy between Zr-modified oxygen vacancy (In-Ov-Zr) and Pt catalyst facilitates methanol synthesis from CO2 hydrogenation via formate route. This is different from Pt/In2O3, which takes CO hydrogenation route.

Effect of ZrO2 on sintering behavior and properties of h-BN/ZrO2 composites by spark plasma sintering

The h-BN/ZrO2 composites with different 3Y–ZrO2 content were prepared by spark plasma sintering at 1800 °C. The sintering behavior, bulk density, apparent porosity, thermal conductivity, thermal expansion coefficient, bending strength, thermal shock resistance, microstructure and phase were analyzed. The optimum specimens were used to test the resistance to corrosion of molten steel for 10, 20, 40, 80 min respectively. The results indicated that ZrO2 could facilitate the sintering process of h-BN matrix under the action of spark plasma. Especially, for the composites with 30 wt% 3Y–ZrO2, the porosity could decrease to 1.1% and the flexural strength could exceed 150 MPa. The microstructure showed the h-BN grains and 3Y–ZrO2 grains are closely combined. The XRD patterns indicated that the t-ZrO2 diffraction peak gradually enhanced with the increase of density. With the increase of erosion time, the erosion rate increased significantly. After the surface of the specimen is eroded, the erosion resistance of the matrix would decrease significantly. This h-BN/ZrO2 could be as side-dam used in the thin strip continuous casting process.

Vacuum sintering of Yb2O3 transparent ceramics: Effect of ZrO2 concentration on structural and optical properties

• Highly transparent ytterbium oxide (Yb 2 O 3 ) ceramics were successfully prepared by vacuum sintering method using ZrO 2 as a sintering aid. • ZrO 2 was found to be an effective sintering additive that can effectively inhibit Yb 2 O 3 grain growth and promote the removal of residual pores. • The effects of ZrO 2 doping concentration on the crystal structure, microstructure, optical transmittance, and band gap of Yb 2 O 3 transparent ceramics were studied for the first time. In this study, highly transparent Yb 2 O 3 ceramics were successfully fabricated via vacuum sintering at 1800 °C for 10 h with ZrO 2 as a sintering additive. The effect of zirconia doping concentration on crystal structure, microstructure, and optical properties of Yb 2 O 3 transparent ceramics was investigated. It was found that the introduction of zirconia could effectively prohibit grain growth while promoting the removal of residual pores. The mean grain size decreased from 39.04 µm to 4.27 µm as the Zr 4+ content increased from 0 to 5 at%. The 3 at% ZrO 2 -doped Yb 2 O 3 transparent ceramics have the best optical quality, with a transmittance of 75% at 1100 nm and about 81% in the mid-infrared region. This study indicates that Yb 2 O 3 transparent ceramics with good optical properties can be obtained by properly adjusting the addition amount of ZrO 2 . On this basis, the absorption spectra, emission spectra, and fluorescence lifetime of Yb 2 O 3 transparent ceramic were investigated. High transmittance and high activation cation density make Yb 2 O 3 transparent ceramics potential candidates for thin-disk laser elements.

Dual effect of ZrO2 on phase separation and crystallization in Li2O–Al2O3–SiO2–P2O5 glasses

AbstractZrO2 is an effective nucleation agent for low‐expansion lithium–aluminum silicate (LAS) glass–ceramic (GC) with high Al2O3 content. However, the effect of ZrO2 is still not fully understood in LAS glasses with low contents of Al2O3 and P2O5. In this work, the effect of ZrO2 on the phase separation and crystallization of Li2O–Al2O3–SiO2–P2O5 glasses were investigated. The results revealed that ZrO2 significantly increased Tg and the crystallization temperature of Li2SiO3 and Li2Si2O5 crystals. Li3PO4 crystals precipitated preferentially in the glass containing 3.6‐mol% ZrO2, wherein Zr was stable in the network and no precipitation of ZrO2 nanocrystals was observed. Moreover, the separation of phosphate‐rich phases in the as‐quenched glasses increased with the addition of ZrO2. The findings of the study revealed a dual role of ZrO2. First, ZrO2 acted as a glass network former rather than a nucleation agent, increasing glass viscosity and the nucleation barrier of Li2SiO3 through its strong network connectivity. Second, as Zr preferentially combined with non‐bridging oxygen to form Si–O–Zr linkages, a sufficient amount of charge‐balancing Li+ ions existed in the network, which promoted the separation of phosphate‐rich phases. It indicated that the incorporation of ZrO2 contributes to the activation of the nucleation role of P2O5, thus contributing to the formation of nanocrystals and fine microstructure of GCs.