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Pulsed Current Activated Sintering of Nanostructured ZrO <sub/>2</sub> and 3YSZ and Their Mechanical Properties
摘要： As nanostructured materials possess high strength, high hardness, excellent ductility and toughness, undoubtedly, more attention has been paid for the application of nanomaterials. When conventional sintering processes are used to sinter nano-sized zirconia powders, concomitant grain growth leads to the destruction of the nanostructure. This focuses attention on consolidation methods in which grain growth can be eliminated or significantly reduced. To accomplish this, rapid sintering methods have been widely used to sinter nano-sized powders. Nanopowders of ZrO2 and 3YSZ were fabricated and rapidly consolidated using high-energy ball milling and the pulsed current activated sintering (PCAS). The sintering behavior and crystallite size ZrO2 and 3YSZ powders were evaluated. A nanostructured dense 3YSZ compact with a relative density of up to 99% was readily obtained within one min. The hardness and fracture toughness of ZrO2 and 3YSZ sintered from powders milled for 10 h were 450 and 1160 kg/mm2, 3 and 4.4 MPa · m1/2. Not only hardness but also fracture toughness of 3YSZ are higher than those of ZrO2.
关键词： ZrO2,3YSZ,Mechanical Properties,Nanomaterials,Sintering
更新于2025-09-23 15:22:29
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Fabrication of Laser Grade Yb: Y2O3 Transparent Ceramics with ZrO2 Additive through Hot Isostatic Pressing
摘要： Laser grade 8 at.% Yb: Y2O3 transparent ceramics were fabricated with ZrO2 as a sintering additive by using hot isostatic pressing. The hot isostatic pressed 8 at.% Yb: Y2O3 transparent ceramics have a small average grain size of 3 μm and a high transmittance of 82.8% in the near-infrared light region. Optical homogeneity is compromised slightly in the visible light region likely because of the presence of nano/micro-scaled pores. Laser output at 1076 nm reaches a maximum power of 1.1 W and a slope efficiency of 6.1%, indicating that the hot isostatic pressed 8 at.% Yb: Y2O3 transparent ceramics have a promising optical quality. An unusual laser damage is observed and believed to be related to ZrO2 additive associated defects.
关键词： ZrO2 additive,hot isostatic pressing,laser grade,Yb: Y2O3,transparent ceramics
更新于2025-09-23 15:21:01
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Ferroelectricity of Hf <sub/>x</sub> Zr <sub/>1?x</sub> O <sub/>2</sub> Thin Films Fabricated Using TiN Stressor and ZrO <sub/>2</sub> Nucleation Techniques
摘要： We studied the ferroelectricity and the leakage current (J) properties of the TiN/ZrO2/HfxZr1?xO2/ZrO2/TiN capacitor (D-ZrO2) with the ZrO2 nucleation layers, comparing to the TiN/HfxZr1?xO2/TiN capacitor (D-TiN) with the TiN stressor layers. The larger ferroelectric phase ratio was achieved by the epitaxial like grain growth of the HfxZr1?xO2 film on the surface of the top- and bottom-ZrO2 nucleation layers. Thus, the larger remanent polarization (2Pr = 29 μC/cm2) of D-ZrO2 was obtained compared to that (24 μC/cm2) of D-TiN. Moreover, the J value of D-ZrO2 was approximately one order of magnitude lower than that of D-TiN. Therefore, these results suggest that the superior ferroelectricity of HZO film can be obtained using the ZrO2 nucleation technique instead of the TiN stressor technique.
关键词： HfxZr1?xO2,Thin Films,Ferroelectricity,ZrO2 Nucleation,TiN Stressor
更新于2025-09-23 15:21:01
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Development of Thick Superhydrophilic TiO <sub/>2</sub> –ZrO <sub/>2</sub> Transparent Coatings Realized through the Inclusion of Poly(methyl methacrylate) and Pluronic-F127
摘要： A thick coating of hierarchically porous double-templated TiO2?ZrO2?PMMA?PF127 with excellent self-cleaning properties and high transmittance has been developed for the first time on glass substrates using a simple dip-coating technique. Comparative studies of this sample with a thick and transparent coating of single-templated TiO2?ZrO2?PMMA have been performed to probe the origin of its exceptional properties. The formation of the composites, successful incorporation of the polymer into the matrix, and the porous nature of the films have been studied. The presence of Ti2+ in the double-templated samples has been confirmed, which suggest the chemisorption of water on the surface of the film. The variation in the self-cleaning properties of the samples on UV-illumination has also been studied. The double-templated film is found to possess the capability of good hydrophilic retention even 2 days after UV-irradiation.
关键词： PF127,self-cleaning,PMMA,transparent coatings,dip-coating,UV-irradiation,TiO2?ZrO2,superhydrophilic
更新于2025-09-23 15:21:01
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In situ fluorine doped ZrO2?x nanotubes for efficient visible light photocatalytic activity
摘要： The F-doped ZrO2?x nanotubes are synthesized by anodic oxidization in a F-containing electrolyte and following a low temperature annealing process. The F-doped ZrO2?x nanotubes exhibit a dramatic increase in visible light absorption and efficient visible light photocatalytic activity which are not possessed to normalized ZrO2. The fluorine in anodic ZrO2 nanotubes plays a vital role in the formation of abundant anion vacancies during the annealing. Combining the doping effect of the residual fluorine element, the band gap of the F-doped ZrO2?x nanotubes reduced from 5.13 to 2.35 eV. Moreover, the transient photocurrent response plots and the photocatalytic experiments reveal the highly effective electrons–holes separation of the F-doped ZrO2?x nanotubes and enhanced visible-light photocatalytic degradation for RhB. The degradation rate of RhB in the presence of the F-doped ZrO2?x nanotubes catalyst has reached up to 83% under 2 h low-power LED light irradiation. In addition, the possible photocatalytic mechanism of the F-doped ZrO2?x nanotubes has been proposed via studying the band structure. It is believed that the F-doped ZrO2?x nanotubes will have a bright future for sustainable energy sources and cleaning environment.
关键词： oxygen vacancies,F-doped ZrO2?x nanotubes,anodic oxidization,visible light photocatalytic activity,band gap narrowing
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 28th International Symposium on Industrial Electronics (ISIE) - Vancouver, BC, Canada (2019.6.12-2019.6.14)] 2019 IEEE 28th International Symposium on Industrial Electronics (ISIE) - Digital Holography for Industrial Applications
摘要： Metal–insulator–metal (MIM) capacitors with full atomic-layer-deposition Al2O3/ZrO2/SiO2/ZrO2/Al2O3 stacks were explored for the first time. As the incorporated SiO2 film thickness increased from 0 to 3 nm, the quadratic and linear voltage coefficients of capacitance (α and β) of the MIM capacitors reduced significantly from positive values to negative ones. For the stack with 3-nm SiO2 film, a capacitance density of 7.40 fF/μm2, α of ?121 ppm/V2, and β of ?116 ppm/V were achieved, together with very low leakage current densities of 3.08 × 10?8 A/cm2 at 5 V at room temperature (RT) and 5.89 × 10?8 A/cm2 at 3.3 V at 125 °C, high breakdown field of 6.05 MV/cm, and high operating voltage of 6.3 V for a 10-year lifetime at RT. Thus, this type of stacks is a very promising candidate for next generation radio frequency and analog/mixed-signal integrated circuits.
关键词： metal-insulator-metal,Al2O3/ZrO2/SiO2/ZrO2/Al2O3,Atomic-layer-deposition,voltage coefficients of capacitance
更新于2025-09-19 17:13:59
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Room-temperature processed ZrO2 interlayer towards efficient planar perovskite solar cells
摘要： The Sn-doped In2O3 transparent conductive (ITO) electrode in planar perovskite solar cells (PSCs) is modified by zirconia (ZrO2) interlayer with low-temperature process. Here the ZrO2 film is prepared by ultraviolet (UV) treatment at room temperature. The effects of the inserted ZrO2 interlayer on the performance of CH3NH3PbI3-xClx-based PSCs have been systemically studied. After optimizing the process, the champion efficiency of PSC with UV-treated ZrO2 interlayer is 19.48%, which is larger than that of the reference PSC (15.56%). The improved performance in the modified devices is primarily ascribed to the reduced trap states and the suppressed carrier recombination at the ITO/SnO2 interface. Our work provides a facile route to boost the photovoltaic performance of PSCs by modifying the surface of transparent conductive electrode at room temperature.
关键词： Photoelectric properties,ITO/SnO2 interface modification,Ultraviolet (UV) treatment,Planar perovskite solar cell,Room-temperature processed ZrO2 interlayer
更新于2025-09-19 17:13:59
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Synthesis, characterization and luminescence properties of ZrBDC:Eu <sup>3+</sup> ,Tb <sup>3+</sup> nanoscaled metal organic frameworks
摘要： Zirconium nanoscaled metal–organic frameworks doped and co-doped with Eu3+ and/or Tb3+ (ZrBDC:Eu3+,Tb3+) have been synthesized by hydrothermal method using 1,4-dicarboxylic acid as linkers. The luminescence spectra obtained indicated that under 254 nm excitation, the as-synthesized ZrBDC:Eu3+,Tb3+ and ZrO2:Eu3+,Tb3+ nanoparticles have multicolour visible emissions at 473, 591, 612 and 701 nm assigned to the 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4 transition of Eu3+ ions and at 488, 582 and 621 nm assigned to 5D4 → 7F, 5D4 → 7F5; 5D4 → 7F4 and 5D4 → 7F3 transitions of Tb3+ ions, respectively. The X-ray diffraction and field emission scanning electron microscopy results suggest that the ZrBDC:Eu3+,Tb3+ nanoscaled metal–organic frameworks can be used as precursors to design the tetragonal phase of ZrO2:Eu3+,Tb3+ nanoparticles with high purity and a narrow size distribution via heat treatment process. The as-prepared ZrO2:Eu3+,Tb3+ nanoparticles have size of about 10-15 nm with BET multipoint surface area of 162 m2/g.
关键词： ZrBDC:Eu3+,Tb3+,254 nm excitation,Zirconium metal–organic frameworks,nanoparticles,ZrO2:Eu3+,Tb3+
更新于2025-09-19 17:13:59
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Analysis of Melt-Pool Behaviors during Selective Laser Melting of AISI 304 Stainless-Steel Composites
摘要： The melt-pool behaviors during selective laser melting (SLM) of Al2O3-reinforced and a eutectic mixture of Al2O3-ZrO2-reinforced AISI 304 stainless-steel composites were numerically analyzed and experimentally validated. The thermal analysis results show that the geometry of the melt pool is significantly dependent on reinforcing particles, owing to the variations in the melting point and the thermal conductivity of the powder mixture. With the use of a eutectic mixture of Al2O3-ZrO2 instead of an Al2O3 reinforcing particle, the maximum temperature of the melt pool was increased. Meanwhile, a negligible corresponding relationship was observed between the cooling rate of both reinforcements. Therefore, it was identified that the liquid lifetime of the melt pool has the effect on the melting behavior, rather than the cooling rate, and the liquid lifetime increases with the eutectic ratio of Al2O3-ZrO2 reinforcement. The temperature gradient at the top surface reduces with the use of an Al2O3-ZrO2 reinforcement particle due to the wider melt pool. Inversely, the temperature gradient in the thickness direction increases with the use of an Al2O3-ZrO2 reinforcement particle. The results of melt-pool behaviors will provide a deep understanding of the effect of reinforcing particles on the dimensional accuracies and properties of fabricated AISI 304 stainless-steel composites.
关键词： FEM,Al2O3,Al2O3-ZrO2,304,composite,SLM,additive manufacturing,selective laser melting,stainless
更新于2025-09-16 10:30:52
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Rapid crystallization of electrohydrodynamically atomized ZrO2 thin films by laser annealing
摘要： This paper aims to provide a simple and rapid fabricating method for solution-based ZrO2 thin films. The ZrO2 thin film was firstly deposited on a 316L stainless steel substrate by electrohydrodynamic atomization. Then the crystallization process was carried out by a 4W Nd:YAG laser with a wavelength of 1064 nm. The morphology, structure and evolution of chemical bonds (Zr and O) were evaluated by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. After laser annealing, the O 1s (O-containing ions in ZrO2) fraction rose from 22.6 % to 51.1 %, and the principal tetragonal phase composition was obtained. The large temperature gradients that derived from the photothermal effect contribute to the fast crystallization during the laser treatments. The tribological and electrochemical corrosion experiments reveal that the laser crystallized films have significantly well wear and corrosion resistance, close to those of conventionally crystallized films. This fabricating method is simple, energy-saving and could achieve the spatially-resolved crystallization of films with a minimal temperature increase on the underlying substrates.
关键词： Laser annealing,ZrO2 thin films,Electrohydrodynamic atomization,Tribological and corrosion properties
更新于2025-09-16 10:30:52