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Nano ZrO2 Synthesis by Extraction of Zr(IV) from ZrO(NO3)2 by PC88A, and Determination of Extraction Impurities by ICP-MS
摘要： High purity Zirconium (Zr) materials are essential in many components of nuclear reactors, especially fuel cladding tubes. Due to the matrix in?uence, determination of impurities in the Zr materials requires separation from the Zr matrix. Among extraction methods, solvent extraction is common and suitable for large-scale production. In this study, extraction capability of Zr(IV) by 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (PC88A) was examined by FT-IR and UV of ZrO(NO3)2 salt, PC88A-toluene solvent, and Zr-PC88A-toluene complex. ZrO2 (obtained from Institute for Technology of Radioactive and Rare Elements—ITRRE), after being separated from the Zr matrix, was determined for impurities using internal standard (indium, In) by 50% of PC88A dissolved in toluene. Separation of impurities from the Zr matrix underwent two stages. First, one cycle of extraction of the Zr matrix and impurities in 3 M HNO3 using 50% PC88A/toluene was conducted. Second, impurities were scrubbed by 4 M HNO3 in two cycles. Results revealed that approximately 74% of Zr(IV) was separated to the organic phase and 26% remained in the aqueous phase. Determination of impurities after separation from the Zr matrix by ICP-MS using internal standard in revealed that the recovery of impurities achieved 95–100%. With the mentioned amount of Zr, the effect of the Zr matrix on the determination of elements by ICP-MS is negligible. Levels of impurities have relative standard deviations (RSD) of less than 6.9% and recovery of 88.6–98.8%. Therefore, the determination of impurities has high reliability and accuracy. The back-extraction of Zr(IV) in organic phase by 1 M H2SO4 has stripped about 99.5% of the Zr matrix back to the aqueous phase. Following this, NH3 was added to the solution containing Zr after back-extraction to form Zr(OH)4 which was then desiccated to produce ZrO2. X-ray Diffraction (XRD), Scanning and Transmission Electron Microscopy (SEM and TEM) images showed that the new ZrO2 product has spherical nanostructure with diameters of less than 25 nm, which is suitable for applications for the treatment of colorants, metal ions in wastewater sources and manufacture of anti-corrosion steel. In addition, the energy dispersive X-ray (EDX) of the new ZrO2 product showed that it has high purity.
关键词： extraction,nano ZrO2,impurities,PC88A,ICP-MS,high purity Zr
更新于2025-09-09 09:28:46
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GaN metal-oxide-semiconductor devices with ZrO2 as dielectric layers
摘要： P-type GaN metal oxide semiconductors (MOS) with ZrO2 dielectrics have been fabricated. Here, H2O and O3 were selected as oxidizers for ZrO2 growth by atomic layer deposition. The MOS devices with O3 oxidant demonstrated a smaller ?at band voltage than that with H2O oxidant. A Ga2O3 interlayer was formed between GaN and O3-grown ZrO2, which can e?ectively decrease interfacial state density to 1.5 × 1011 cm?2. Meanwhile, the innovation of AlZnO (AZO)/Ag nanowires (AgNWs)/AlZnO composite electrodes can further decrease the ?at band voltage to about a half compared to that with traditional Cr/Au electrodes and superior electrical performance was achieved.
关键词： Silver nanowires,MOS,ZrO2,Atomic layer deposition,p-GaN
更新于2025-09-09 09:28:46
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Stability and Microbial Toxicity of HfO <sub/>2</sub> and ZrO <sub/>2</sub> Nanoparticles for Photolithography
摘要： HfO2 and ZrO2 nanoparticles (NPs) have gained attention as components of photoresists for next-generation photolithography. Coating of these NPs with organic ligands has been shown to increase their efficiency in photolithography. This study evaluated the microbial toxicity of HfO2 and ZrO2 NPs coated with benzoate, isobutyrate, or methacrylate towards heterotrophic aerobes, methanogens, and the bioluminescent bacterium, Aliivibrio fischeri. The stability of NPs in the media was assessed as a function of zeta potential, particle size distribution, and leaching analyses. NP dispersions were unstable in all bioassay media, resulting in particle aggregation and settling. Leaching tests showed that dissolution of the organic ligands from the NPs varied widely depending on the nanomaterial and medium considered. The NPs were harmless to aerobic heterotrophs and methanogens at high concentrations (800-1200 mg L-1). In contrast, they displayed low to moderate toxicity to A. fischeri (50% inhibition at 286-1372 mg L-1), with benzoate-coated NPs causing the highest inhibition. Further analyses confirmed that the inhibition observed in assays with A. fischeri should be attributed to the coated NPs rather than to the dissolved organic ligands. Overall, the NP photoresists tested in this study are unlikely to exert acute microbial toxicity at environmentally relevant concentrations (sub-ppm levels).
关键词： stability,photolithography,HfO2,ZrO2,nanoparticles,microbial toxicity,leaching
更新于2025-09-09 09:28:46
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Influence of 120 MeV S9+ ion irradiation on structural, optical and morphological properties of zirconium oxide thin films deposited by RF sputtering
摘要： The calibrated and controlled swift heavy ions (SHI) beam irradiation generates defects which can cause modifications in various properties of the materials such as structural, optical, magnetic, morphological, and chemical etc. The passage of ion through the target material causes the nuclear energy losses (Sn) and electronic energy losses (Se). The Se dominates over Sn in SHI irradiation. In the present study, ZrO2 thin films were grown on silicon and glass substrate by using RF sputtering deposition technique. For the purpose of modifications induced by swift heavy ions, these films were irradiated by a 120 MeV S9+ ion beam of 1 pnA current, with varying ion fluences from 5E12 to 1E13 ions/cm2, using the tandem accelerator at the Inter University Accelerator Center (IUAC), New Delhi, India. The X-ray diffraction (XRD) patterns confirmed the formation of monoclinic and tetragonal phases and it was observed that XRD peak intensities increased up to the fluence of 5E12 ions/cm2 followed by opposite behavior at higher fluences. Atomic force microscope (AFM) study revealed the increased surface roughness after SHI irradiation. In addition to it, the formation of electronic transition states in optical band gap region and enhancement of absorption edge was observed from UV- visible spectroscopy (UV-Vis) results due to which direct band gap energy value decreased from those of un-irradiated samples. Photoluminescence (PL) broad emission spectra were determined using the excitation wavelength at 290 nm with the prominent peak at 415 nm which can be ascribed to Zr vacancies due to band edge emission as a result of free- exciton recombination. Rutherford backscattering spectrometry (RBS) technique was used for depth profiling and elemental composition in zirconia thin films. The expected role of electronic energy loss during ion irradiation to modify the properties of the material has been discussed.
关键词： PL,ZrO2 thin films,XRD,UV-Vis,AFM,RBS,SHI irradiation
更新于2025-09-09 09:28:46
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Quantum cutting properties of Tb3+/Yb3+ co-doped ZrO2-SiO2 nano-crystalized glasses synthesized via a sol-gel route
摘要： Tb3+/Yb3+ co-doped ZrO2-SiO2 nano-crystallized glasses were prepared by a sol-gel process. The crystal structure and optical properties including down-conversion photoluminescence (or, quantum cutting) of the Tb3+-Yb3+ system with respect to gel heat treatment temperature were investigated by X-ray diffraction (XRD), Raman, photoluminescence (PL), and PL decay curves analysis. The energy transfer efficiency from Tb3+ to Yb3+ ions, which converts one photon to two photons with lower energy, increased with heat-treatment temperature. Furthermore, the oxidation state of Tb4+ ions was suspected to influence the emission intensity of Tb3+ and energy conversion efficiency. Thus, a post-treatment reduction was applied to the sample heated at 1100 oC by annealing it at 1100 oC for 1 h under 5%H2/95%N2 reductive atmosphere. Consequently, the thermodynamically generated Tb4+ ions were reduced to a trivalent state, leading to higher energy transfer efficiency.
关键词： ZrO2 nanocrystals,Sol-gel method,photoluminescence,quantum cutting,Tb3+-Yb3+ pair,Tb4+ ions
更新于2025-09-09 09:28:46
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Fabrication and analysis of the structural phase transition of ZrO <sub/>2</sub> nanoparticles using modified facile sol–gel route
摘要： The synthesis of zirconia nanoparticles is achieved through a modified facile sol–gel route. The as-prepared gel is analyzed thermally using TGA and DTA techniques to spot the crystallization process of zirconia nanoparticles. The prepared gel is then annealed at different temperatures and the structure was found to change between tetragonal and monoclinic crystal systems. The first stable tetragonal phase is achieved after annealing for 2 h at 400°C. The annealed powders between 600°C and 800°C demonstrate mixed tetragonal/monoclinic phases. Annealing at 1000°C and higher temperatures up to 1200°C resulted in pure monoclinic phase. Cubic phase was not detected within the annealing temperature range in this study. The elemental analysis of the annealed powder confirmed the formation of zirconia nanoparticles with the chemical formula ZrO2. The FTIR spectra of the annealed samples introduced a variation in the vibrational bands especially around the phase transition temperature. HR-TEM images reported the formation of nano-zirconia crystals with apparently large particle sizes. The optical energy gap of zirconia nanoparticles is investigated and determined.
关键词： ZrO2 nanoparticles,HR-TEM,sol–gel synthesis,EDAX,optical energy gap
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland, New Zealand (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Influence Analysis of ZrO<inf>2</inf> Ceramic for Cellular Phones on 5G mm-Wave Antenna Performance
摘要： In this paper, the influences of ZrO2 ceramic on the fifth generation mobile communications (5G) millimeter-wave (mm-Wave) antenna performance are studied. A 28-GHz 2 × 2 non-stacked patch antenna array and a 28-GHz 2 × 2 stacked patch antenna array are designed on dielectric substrates as the performance baseline. Based on the two types of antenna arrays, various ZrO2 ceramic thicknesses and various gaps between the ZrO2 ceramic and the antenna arrays are simulated to get quick understanding of the ZrO2 ceramic influence on the antenna performance. From the simulated results, it can be found that the ZrO2 ceramic has different influences on different types of antenna arrays. Besides, for both of the two types of antenna arrays, when the thicknesses of ZrO2 ceramic are close or equal to integer multiples of 0.5 guided wavelengths ((cid:540)g), the antenna performance in the material-loading cases gets close to that in the free space (FS). Also, when the thicknesses of ZrO2 ceramic are close or equal to odd multiples of 0.25 (cid:540)g and the gaps between the ZrO2 ceramic and the antenna array are close or equal to integer multiples 0.5 FS wavelengths ((cid:540)0), the focusing effects of electromagnetic (EM) beams get significant for both arrays. The findings comply with the EM wave propagation theory and can be applied to radome designs of Terahertz (THz) antenna arrays.
关键词： 5G,mm-Wave,ZrO2,THz,ceramic,antenna
更新于2025-09-09 09:28:46
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Phytosynthesis of Au and Au/ZrO <sub/>2</sub> bi-Phasic System Nanoparticles with Evaluation of Their Colloidal Stability
摘要： Due to its easy availability, preparation, handling and non-toxic nature, Equisetum arvense horsetail extract was chosen as a reducing, stabilizing and functionalizing agent for Au and bi-phasic Au/ZrO2 nanoparticle phytosynthesis–inorganic nanoparticle synthesis mediated by plant extract. We studied Au and bi-phasic Au/ZrO2 nanoparticles in colloids by various physical-chemical and analytical methods over 5 weeks. Dynamic Light Scattering and Scanning Transmission Electron Microscopy compared core and hydrodynamic diameters of nanoparticles. (cid:2)-potential measurement indirectly determined nanoparticles stability in liquid medium. Ultraviolet–Visible Spectroscopy characterized basic absorbance maxima for both Au and the bi-phasic Au/ZrO2 system. Finally, total metal concentration was determined using Inductively Coupled Plasma Mass Spectrometry. (cid:2)-potential measurements proved satisfactory stability of both Au (?13(cid:3)4 to ?17 mV) and Au/ZrO2 nanoparticles (?14(cid:3)1 to ?17(cid:3)5 mV) over the experimental period. Scanning Transmission Electron Microscopy with Selected Area Diffraction analysis con?rmed nanoparticles crystalline nature, and we determined 24 nm and 40 nm core nanogold diameters in Au and Au/ZrO2 nanoparticle colloids. Dynamic light scattering analysis con?rmed the dichotomy between particle sizes in liquid medium in the hundreds of nanometers measured, and long-term measurements con?rmed reasonable colloid stability—a paramount parameter for potential nanoparticles applications; especially in heterogeneous catalysis.
关键词： Stability,Au/ZrO2 Nanoparticles,Phytosynthesis,Colloid,Au Nanoparticles
更新于2025-09-04 15:30:14
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ZrO2/Fe2O3/RGO nanocomposite: Good photocatalyst for dyes degradation
摘要： We report a ZrO2/Fe2O3/RGO nanocomposite was synthesized via insitu-hydrothermal method and characterized by X-ray di?raction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), UV–Visible di?use re?ectance spectrophotometer (DRS), Raman, Photoluminescence (PL) and BET analysis to study the structural, morphological and optical properties. FESEM images declares that ZrO2 particles are uniform discs like nanostructure shape with clear facets and narrow size distribution; Fe2O3 were agglomerated, which leads to have completely dispersed with the rGO and forms a ZrO2/Fe2O3/RGO nanocomposite. The elemental composition (Zr, Fe, O and C) of as-prepared ZrO2/Fe2O3/RGO nanocomposite was con?rmed using EDX. FTIR and Raman analysis con?rmed the GO was reduced into RGO during the synthesis of ZrO2/Fe2O3/RGO nanocomposite. The synthesized catalysts were examined for photocatalytic activity by the degradation of Congo Red (CR) and Acetophenone (AP) under visible light illumination, these results clearly prompted that ZrO2/Fe2O3/RGO nanocomposite shows a high photodegradation e?ciency of CR and AP under visible light illumination than ZrO2/Fe2O3, pure Fe2O3 and pure ZrO2.
关键词： Hydrothermal,Raman,Photocatalytic degradation,Congo red and Acetophenone,ZrO2/Fe2O3/RGO nanocomposite
更新于2025-09-04 15:30:14
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Total-Ionizing-Dose Response of MoS2 Transistors with ZrO2 and h-BN Gate Dielectrics
摘要： The total-ionizing-dose response of few-layer MoS2 transistors with ZrO2 or h-BN gate dielectrics is investigated under various bias conditions. Defects in MoS2 and surrounding dielectric layers significantly affect radiation-induced trapping. For devices with ZrO2 dielectrics, much larger negative Vth shifts and peak transconductance degradation are observed for irradiation under negative and ground bias than under positive bias. h-BN devices exhibit positive threshold voltage shifts under negative-bias irradiation. For both ZrO2 and h-BN passivated devices, the peak transconductance degradation results from charge trapping at the surface of the MoS2 or in nearby oxides. Changes in defect energy distributions of MoS2 FETs during X-ray irradiation are characterized via temperature-dependent low-frequency noise measurements. Density functional theory calculations are performed to provide insight into the pertinent defects.
关键词： DFT,MoS2 FET,low frequency noise,ZrO2,h-BN,2 dimension,X-ray
更新于2025-09-04 15:30:14