Presence Of ZrO2 Nanoparticles Research Articles

In-situ synthesized nanostructured t-ZrO2/La2(Zr0.75Ce0.25)2O7 composite thermal barrier coatings

As we all know, the poor toughness is an important factor that leads thermal barrier coatings to prematurely fail, which has been recognized as one of the urgent problems that need to be addressed. Herein, the nanostructured t-ZrO2/La2(Zr0.75Ce0.25)2O7 (LCZ) composite TBCs were constructed in-situ from plasma spraying. The microstructure and phase composition of nanostructured LCZ feedstocks and as-sprayed coatings were analysed. Moreover, the mechanism of in-situ synthesized nanostructured t-ZrO2/LCZ coatings was discussed in detail. Results show that as-sprayed coatings have the characteristics of bi-modal and dual-phase structures. The unmelted nanostructured LCZ feedstocks and in-situ synthesized ZrO2 nanoparticles are included in the nanostructured zone. The phase structure of coatings consists of fluorite LCZ and tetragonal ZrO2 (t-ZrO2). The presence of ZrO2 nanoparticles is derived from the decomposition of LCZ feedstocks during plasma spraying.

Modeling and Optimizing the Penetration in the Submerged Arc Welding Process in the Presence of ZrO2 Nanoparticles

Abstract Penetration is one of the most vital parameters because of its influences on weld strength and weld quality. Choosing the input parameters in submerged arc welding (SAW) has significant effects on input heat into the weld pool, which affects the quality of weldment. The amazing advancement of nanotechnology in various industrial areas persuaded researchers to use nanoparticles in new research. Zirconium dioxide (ZrO2) nanoparticles were selected in order to identify their effects in the weld pool in combination with other welding input parameters. The five-level, five-parameter central composite rotatable design, response surface methodology, the slime mold algorithm, and Harris hawks optimization were utilized to design and develop the research and finally to predict and optimize the weld penetration affected by the arc voltage, welding current, nozzle-to-plate distance, welding speed, and the thickness of ZrO2 nanoparticles coated on ST-37 steel. The main and interaction effects of input parameters on weld penetration were drawn. The results demonstrated that weld penetration decreased initially by increasing the thickness of ZrO2 nanoparticles up to 0.25 mm, which was due to reversing Marangoni convection mode. Furthermore, weld penetration increased with increase in ZrO2 nanoparticles above thicknesses of 0.75 mm. The reason for increase in weld penetration was because of the fact the ZrO2 nanoparticles have low thermal conductivity, which leads to less heat transfer. The results confirmed that the accuracy of model obtained by slime mold algorithm was 5.2 % more than response surface methodology.

Very high upper critical fields and enhanced critical current densities in Nb3Sn superconductors based on Nb–Ta–Zr alloys and internal oxidation

The inhibition of Nb3Sn grain growth in the presence of ZrO2 nanoparticles appears to be one of the most promising method for pushing the critical current densities of Nb3Sn superconducting wires to levels that meet the requirements set for the Future Circular Collider. We have investigated the effect of ZrO2 nanoparticles formed by the internal oxidation of Zr on the superconducting properties and microstructure of Nb3Sn formed from Nb-1 wt%Zr, Nb-7.5 wt%Ta, Nb-7.5 wt%Ta-1 wt%Zr and Nb-7.5 wt%Ta-2 wt%Zr alloys. A monofilamentary wire configuration was used, with a 0.22 mm outer diameter Nb-alloy tube containing a core of powdered metal oxide (SnO2, CuO or MoO3) as oxygen source and successive deposits of Cu, Sn and Cu on the outer surface. As determined from inductive measurements, the layer critical current densities of the samples based on Nb alloys with internally oxidized Zr were superior to those based on Nb-7.5 wt%Ta. The samples based on Nb-7.5 wt%Ta-1 wt%Zr and Nb-7.5 wt%Ta-2 wt%Zr showed higher critical current densities at high magnetic fields (above 10–15 T), and upper critical fields exceeding 28.5 T at 4.2 K (99% normal state resistivity criterion). A record value of 29.2 T of the upper critical field at 4.2 K was obtained on samples based on Nb-7.5 wt%Ta-2 wt%Zr. Hypotheses are proposed and discussed for explaining this unexpected increase of the upper critical field, by considering the possible effects of non-oxidized Zr on the superconducting properties of Nb3Sn and of the oxidized Zr on the formation and microchemistry of Nb3Sn. Regardless of sample type the Nb3Sn grains observed in our samples have an aspect ratio of 1.5–1.7. When compared in the short axis direction, the mean distance between grain boundary intercepts (lineal intercept method) is ∼40% smaller in the samples with internally oxidized Zr than in the reference samples based on Nb-7.5 wt%Ta. In the long axis direction the reduction is of 20%–30%.

A comparison of ZrO2 nanoparticle reinforced Ni–W, Ni–B and Ni–Cu matrix nanocomposites

In this work, the structure and properties of ZrO2 nanoparticle reinforced Ni–W, Ni–B and Ni–Cu matrix nanocomposite coatings were comparatively studied. Their surface morphology, composition, microstructure, topography, hardness, wear and corrosion resistance were examined by various methods . The nanocomposites exhibit dense, nodular-like morphology with nanocrystalline structure. The results show that the ZrO2 particles have homogeneously dispersed in the nanocomposites. The formation of the protrusion structure was partly attributed to the heterogeneous distribution of the electric field. The presence of ZrO2 nanoparticles could refine the crystallite size of the Ni–W, Ni–B and Ni–Cu alloy matrix to 12.5 ± 1, 10.5 ± 0.5 and 15 ± 0.1 nm, respectively. The corrosion resistance of these nanocomposites can be improved by the incorporation of ZrO2 nanoparticles into the alloy matrix. The R a of Ni–W/ZrO2, Ni–B/ZrO2 and Ni–Cu/ZrO2 nanocomposites are about 53 ± 3, 69 ± 2, 18 ± 1 nm, respectively, expressing the rougher surface of Ni–B/ZrO2 compared to the others. It indicated that the composition of these alloy matrix have different crystallite size, which could affect the surface roughness of the electrodeposits. The inclusion of ZrO2 particles in Ni-based alloys could enhance its properties. The reinforcement effect of the anti-wear properties of the nanocomposites was proposed. The R ct value of the Ni–W–ZrO2, Ni–B–ZrO2, Ni–Cu–ZrO2 were 50.93, 105.18, 44.67 kΩ · cm2, respectively, indicating that the Ni–B–ZrO2 nanocomposite coating has the highest corrosion resistance. The R ct values depends on not only the composition of the coatings, but also the electrodeposition conditions, which influence the crystallize size and compactness of the electrodeposits. The order of the microhardness and anti-wear properties is Ni–W–ZrO2 > Ni–B–ZrO2 > Ni–Cu–ZrO2.

Nanozirconia polymer composite porous membrane prepared by sustainable immersion precipitation method for use as electrolyte in flexible supercapacitors

We report ZrO2-polymer nanocomposite porous membranes prepared by one step phase inversion method with the aim to study a) the effect of ZrO2 nanofiller on the physiochemical and electrochemical properties of the membranes, and b) the viability of the optimized membrane as an electrolyte in energy storage devices. The interaction of ZrO2 nanoparticles with the polymer and liquid electrolyte has been investigated in details using scanning electron microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The microporous structure, liquid electrolyte uptake and ionic conductivity of the nanocomposite membranes have been found to be affected by presence of ZrO2 nanoparticles. The electrolyte membrane with 3 wt.% ZrO2 shows the highest ionic conductivity of ∼4.4 mS cm−1 with a liquid electrolyte retention of ∼375 % and electrochemical stability of ∼4.25 V when soaked in a sodium-ion conducting organic electrolyte. The performance of the highest conducting nanocomposite membrane in symmetric electrical double-layer capacitor (EDLC) has been observed to be better as compared to that of un-doped electrolyte membranes. The EDLC fabricated using the optimized electrolyte membrane and activated carbon electrodes exhibits specific capacitance ∼103 F g−1 and is stable up to 50,000 charge–discharge cycles with specific energy ∼10.2 Wh kg−1, specific power ∼14.2 kW kg−1, and Coulombic efficiency ∼ 99.8 %.

Nano-ZrO2 filled high-density polyethylene composites: Structure, thermal properties, and the influence γ-irradiation

High-density polyethylene (HDPE) composites with different amounts of ZrO2 nanoparticles (1–20 vol%) were prepared by high-pressure thermal pressing. The effect of γ-irradiation on their structural and thermal properties was investigated using small-angle neutron scattering (SANS), X-ray diffraction (XRD), Raman spectroscopy, infrared spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). SANS analysis confirmed good dispersion of the nanoparticles in HDPE matrix. Upon exposure to γ-radiation only small changes in the lattice parameters and the crystalinity degree occurred for both HDPE and the nanocomposities. More significant changes for irradiated HDPE were observed in DSC-derived parameters, including the decrease in the melting point, and increase in crystalinity degree. This trend was even more pronounced for the nanocomposities. A possible explanation assuming resonant enchantment of polymer chain scission in the presence of ZrO2 nanoparticles is discussed. The extent of radiation-induced oxidation was essentially the same for pure HDPE and the nanocomposities, suggesting that the process is diffusion controlled. The thermal stability of the irradiated composites was somehow higher than that pure HDPE.

Properties of Zirconia/Polyaniline hybrid nanocomposites and their application as photocatalysts for degradation of model pollutants

A serie of novel ZrO2/Polyaniline (PANI) hybrid nanocomposite powders were successfully synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate (APS) in water, in the presence of ZrO2 nanoparticles. Syntheses were performed at initial ZrO2/aniline mole ratios 50, 100 and 150 to produce ZP-50, ZP-100 and ZP-150. The morphological, structural, and optical properties of the synthesized nanocomposites were studied using Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Raman, UV-Vis and Electron-paramagnetic resonance (EPR) spectroscopies. EPR spectra of ZP-50 and ZP-100 nanocomposites showed the presence of intensive peak at the g-values comparable to that for free electrons (2.0023) indicating the presence of oligo/poly (semiquinone radical cations), i.e. polarons as charge carriers in PANI part; ZP-150 showed weak polaron peak of PANI, and peak that can be assigned to defects in zirconia matrix (Zr3+, oxygen vacancies). The monoclinic crystal structure of ZrO2 nanoparticles in all nanocomposites was confirmed by XRD and by Raman spectroscopy. The photocatalytic activities of ZP nanocomposites were evaluated using the photocatalytic degradation of trichlorophenol (TCP) and Rhodamine B model compounds and compared with the activity of bare ZrO2 nanoparticles. Enhanced degradation efficiencies of nanocomposites regarding TCP degradation were observed.

Effect of ZrO2 Nanoparticles on the Microstructure of Al-Si-Cu Filler for Low-Temperature Al Brazing Applications

In this study, the effect of ZrO2 nanoparticles on Al-12Si-20Cu alloy has been studied as a filler metal for aluminum brazing. The microstructural and thermal characterizations are performed using X-ray diffraction (XRD), scanning electron microscope (SEM), and differential thermal analysis (DTA). The intermetallic compound (IMC) phases are identified by the energy-dispersive spectroscopy analysis coupled with the SEM. The filler spreading test is performed according to JIS-Z-3197 standard. XRD and SEM analyses confirm the presence of Si particles, the CuAl2 (θ) intermetallic, and the eutectic structures of Al-Si, Al-Cu, and Al-Si-Cu in the Al matrix in the monolithic and composite samples. It is observed that when the ZrO2 is added in the alloy, the CuAl2 IMCs and Si particles are found to be dispersed uniformly in the Al matrix up to 0.05 wt pct ZrO2. DTA results show that the liquidus temperature of Al-12Si-20Cu filler metal is dropped from ~806.78 K to 804.6 K (533.78 °C to 531.6 °C) with a lowering of 2 K (2 °C) in liquidus temperature, when the amount of ZrO2 is increased up to 0.05 wt pct. It is also shown that the presence of ZrO2 nanoparticles in the filler metal has no deleterious effect on wettability up to 0.05 wt pct of ZrO2. The ultimate tensile strength and elongation percentage are also found to improve with the addition of ZrO2 nanoparticles in the Al-12Si-20Cu alloy.

Preparation of Zn-ZrO<sub>2</sub> Nanocomposite Coating by DC and Pulsed Current Electrodeposition Technique with Low Current Density

In the present work, Zn-ZrO2nanocomposite coatings were deposited on the copper substrate through DC and pulse electrodeposition technique with low current density (10 mA/cm2). The effect addition of ZrO2nanoparticles and pulse current were studied. The surface morphology, microhardness and erosion resistance of Zn-ZrO2nanocomposite coating were evaluated. The result shows that, with the addition of ZrO2particles, the surface morphology of Zn-ZrO2nanocomposite coating was smoother. Phase identification by XRD confirm that Zn layer had been sucessfully deposited. The presence of ZrO2nanoparticles was not detected. Compared to DC, pulsed current electrodeposition technique showed higher cathodic efficiency, better microhardness and good erosion resistance.

Morphology and Thermal Stability of Electrically Conducting Nanocomposites Prepared by Sulfosalicylic Acid Micelles Assisted Polymerization of Aniline in Presence of ZrO2 Nanoparticles

Electrically conductive polyaniline (Pani)/zirconium oxide (ZrO2) nanocomposites were prepared by in-situ oxidative polymerization of aniline in the presence of sulfosalicylic acid (SSA), HCl and different amounts of ZrO2 nanoparticles. Pani/ZrO2 nanocomposites were characterized by Fourier Transform Infra-Red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The stability of the nanocomposites in terms of DC electrical conductivity retention was also studied in ambient atmosphere by isothermal ageing and cyclic ageing techniques. Pani/ZrO2 nanocomposites were observed to be more conducting than Pani but showed poorer stability in terms of DC electrical conductivity retention under ambient environmental conditions.

Photocatalytic properties of ZrO2 nanoparticles in removal of nitrophenol from aquatic solution

ZrO2 nanopowder was prepared by the sol-gel auto-combustion method. The product was characterized by X-ray diffraction (XRD), energy dispersive analysis of X-ray (EDX) and scanning electron microscopy (SEM). The average crystalline size of ZrO2 was obtained 62 nm. Also, photocatalytic removal of nitrophenol from aqueous solution by using nanoscale ZrO2 under UV light irradiation was studied. The effect of initial pollution concentrations in 3, 5 and 10 ppm in presence of ZrO2 nanoparticles was studied in photocatalytic degradation process. Nitrophenol was degraded 84, 78 and 66% in the presence of 0.04 g of ZrO2 within 70 minutes.

A Clean Procedure for Synthesis of Pyrido[d]Pyrimidine Derivatives Under Solvent-Free Conditions Catalyzed by ZrO2 Nanoparticles

A simple one-pot method for the preparation of 7-amino-2,4-dioxo-5-aryl-1,2,3,4-tetrahydropyrido[2,3- d]pyrimidine-6-carbonitriles 4 from aromatic aldehydes, malononitrile and 4(6)-aminouracil in the presence of ZrO2 nanoparticles (ZrO2 NPs) as an efficient heterogeneous catalyst is described. The procedure has the advantages of high yields (86-97%), short reaction time (2h) and an environmentally friendly specificity.

Preparation and Characterization of Conductive Polyaniline/Zirconia Nanoparticles Composites

Conductive polyaniline/zirconia (PANI/ZrO2) composites have been synthesized by in-situ polymerization of aniline in the presence of ZrO2 nanoparticles. The structure and morph- ology of composites were characterized by Fourier-transform infrared spectra (FTIR), thermo- gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The conductivity was also investigated. The results showed that PANI and ZrO2 nanoparticles were not simply blended, and a strong interaction existed at the interface of ZrO2 and PANI. It was probably a composite at molecular level. The composites were more thermal stability than that of the pure PANI. XRD analyses confirmed PANI deposited on the surface of ZrO2 nanoparticles had no effect on crystallization performance of ZrO2 nanoparticles. Electrical conductivity measurements indicated that the conductivity of PANI/ZrO2 composites was much higher than that of PANI and the maximum conductivity obtained was 11.27S/cm at 15 wt% of ZrO2 nanoparticles.

Adsorption of Anionic, Cationic and Nonionic Surfactants on Carbonate Rock in Presence of ZrO2 Nanoparticles

The adsorption of surfactants at the solid–water interface is important for the control of wetting, lubrication, detergency and in mineral flotation.We have studied the adsorptions of different types of surfactants, cationic (Dodecyl trimethylammonium bromide, DTAB), anionic (sodium dodecyl sulfate, SDS) and non-anionic (lauryl alcohol-7 mole ethoxylate, LA7) on carbonate rock in presence of zirconium oxide spherical nanoparticles (17-19nm). ZrO2 nanoparticles with tetrahedral structure have significant effect on adsorption of surfactants on the carbonate rock. We have used the measured conductivities to determine the rate of adsorption of surfactants at rock-water interfaces. The conductivity of DTAB in aqueous solutions containing calcite powder decreases more than the other surfactants in contact with ZrO2 nanoparticles. We have also investigated the adsorption of surfactants at the air-water interface. The presence of nanoparticles, as demonstrated by our experiments, enhances the surface activity and surface adsorption of the surfactants through electrostatic forces or formation of nanostructures. Dynamic light structuring data shows similar aggregation number of nanoparticles in presence of nanoparticles.