ZrO2 Nanoparticles Research Articles

Biomedical Applications of Zirconia-Based Nanomaterials: Challenges and Future Perspectives.

ZrO2 nanoparticles have received substantially increased attention in every field of life owing to their wide range of applications. Zirconium oxide is a commercially economical, non-hazardous, and sustainable metal oxide having diversified potential applications. ZrO2 NPs play a vast role in the domain of medicine and pharmacy such as anticancer, antibacterial, and antioxidant agents and tissue engineering owing to their reliable curative biomedical applications. In this review article, we address all of the medical and biomedical applications of ZrO2 NPs prepared through various approaches in a critical way. ZrO2 is a bio-ceramic substance that has received increased attention in biomimetic scaffolds owing to its high mechanical strength, excellent biocompatibility, and high chemical stability. ZrO2 NPs have demonstrated potential anticancer activity against various cancer cells. ZrO2-based nanomaterials have exhibited potential antibacterial activity against various bacterial strains and have also demonstrated excellent antioxidant activity. The ZrO2 nanocomposite also exhibits highly sensitive biosensing activity toward the sensing of glucose and other biological species.

Green synthesis of ZrO2 nanoparticles by Phyllanthus niruri extract and its tensile and high temperature wear behaviour of Al2017A/hBN composites

Green synthesis of ZrO2 nanoparticles by Phyllanthus niruri extract and its tensile and high temperature wear behaviour of Al2017A/hBN composites

Study on the Wear Resistance of Ni-Co-ZrO2 Composite Coatings with Different ZrO2 Nanoparticle Concentrations Prepared Using Electrodeposition on the Micro-Surface of Spindle Hook Teeth

To improve the wear resistance of the surface of the cotton picker spindle, a Ni-Co-ZrO2 composite coating with different ZrO2 nanoparticle concentrations was prepared using electrodeposition technology on the micro surface of spindle hook teeth, and the morphologies of the surface and cross-section, element contents, grain sizes, microhardness and friction coefficients of the Ni-Co-ZrO2 composite coating were obtained; a simulated wear test was conducted based on the independently developed spindle hook tooth wear device, and the morphologies and elemental distributions of the composite coating before and after wear were obtained; the effects of different ZrO2 nanoparticle concentrations (0, 2, 4, 6, 8 g/L) on the morphology, element content, grain size, microhardness, friction coefficient and wear resistance of the coating were discussed. The test results indicated that compared with Ni-Co coatings, Ni-Co-ZrO2 composite coatings featured a more compact coating structure, a greater coating thickness, and a smaller grain size. The presence of ZrO2 nanoparticles led to further improvement of the coating’s microhardness, friction coefficient and wear resistance. When the mass concentration of ZrO2 nanoparticles reached 4 g/L, the microhardness of Ni-Co-ZrO2 composite coating reached the maximum value, 545.4 Hv0.1, and the friction coefficient decreased to 0.06. At the same time, in the simulated wear test, the composite coating with this concentration had the smallest wear area and the highest wear resistance.

The Effect of Zirconia Nanoparticles on Thermal, Mechanical, and Corrosion Behavior of Nanocomposite Epoxy Coatings on Steel Substrates.

Zirconia (ZrO2) nanoparticles (1-3 wt.%) were incorporated into the epoxy matrix using the ultra-sonication mixing method of dispersion to manufacture nanocomposite coatings. An automatic applicator was used to prepare the coating samples on a stainless steel substrate. The influence of ZrO2 nanoparticles on the physicochemical characteristics of epoxy coatings was evaluated using energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), thermos-gravimetric analysis (TGA), elastic modulus, and micro-hardness measurement with the nano-indentation technique. The corrosion stability during immersion in 3.5% NaCl solution was monitored using electrochemical impedance spectroscopy (EIS). All ZrO2-containing coatings showed better corrosion stability and adhesion than pure epoxy coating. Epoxy coating incorporated with 2% ZrO2 exhibited the greatest values of corrosion resistance and adhesion due to the effect of nanoparticle properties and their better de-agglomeration in the epoxy matrix than pure epoxy coating.

Neem gum (Azadirachta indicia) facilitated green synthesis of TiO2 and ZrO2 nanoparticles as antimicrobial agents

Neem gum (Azadirachta indicia) facilitated green synthesis of TiO2 and ZrO2 nanoparticles as antimicrobial agents

Effect of nano ZrO2 addition on the properties of Ca0.86Sr0.14CuO2 added Bi 2223 composites

Effect of introducing nano ZrO2 particles into (Ca,Sr)CuO2 added Bi 2223 superconductor composites is studied. Microstructures revealed that 20 mol. % (Ca,Sr)CuO2 phase added to Bi 2223 formed as micron sized particles among the Bi 2223 platelet shaped grains. Distribution of (Ca,Sr)CuO2 in Bi 2223 has enhanced the critical current density (Jc) and flux pinning force density (Fp ) substantially to fields up to 9 T at 20 K. Introduction of nano ZrO2 into the composite reacted with (Ca,Sr)CuO2 particles and formed additional secondary phases of increasing amount with a rise in ZrO2 content. This resulted in lowering of Jc(0) due to a gradual reduction in the fraction of superconducting phases, but retained the enhanced field range in which flux pinning was achieved. At 10 wt.% addition of ZrO2, Bi 2223 phase was suppressed, and Bi 2212 phase was promoted. Scaling behaviour of pinning force density has shown the dominant mechanism at low fields to be normal surface pinning due to interfacial defects. The fact that (Ca,Sr)CuO2 distributes itself as fine spherical particles in Bi 2223, without causing degradation of the superconducting matrix material, is of significance and opens up a scope to optimize the microstructures further for enhancement of flux pinning.

Comparative Evaluation of Compressive and Diametral Tensile Strength in Die Stone Reinforced With Different Types of Nanoparticles: An In Vitro Study.

To investigate the effect of different types of nanoparticles on the compressive strength (CS) and diametral tensile strength (DTS) of type IV dental stones. A total of 100 specimens were made from the mould for all five groups. Four commercially available nanoparticles (aluminium oxide (Al2O3), silicon dioxide (SiO2), zinc oxide (ZnO), and zirconium oxide (ZrO2)) were used in this study in a concentration of 10%. CS and DTS tests were performed in a universal test machine. The data were statistically analysed using ANOVA and Student's t-test. The interaction between nanoparticles and the type of dental stone was found to be statistically significant (p < 0.05). CS and DTS values decreased by adding all four nanoparticles. The lowest CS and DTS were observed in 10% ZnO nanoparticles when added to type IV dental stone. It was concluded that the addition of nanoparticles (Al2O3, SiO2, ZnO, and ZrO2) to die stonesignificantly decreased the CS and DTS for all groups. Among all groups, the incorporation of 10% ZrO2 nanoparticles (group E) to die stone showed significantly less decrease in CSandDTS compared to Al2O3, SiO2, and ZnO. Incorporation of ZnO nanoparticles, on the other hand, showed a significantly more amount of decrease in theCSandDTScompared to Al2O3, SiO2, and ZrO2.

Physical-chemical properties and tribological characterization of water-glycerine based metal oxide nanofluids

Nanofluids have been recently used in minimum quantity lubrication (MQL) applications to counteract the disadvantages of conventional cooling lubrication. However, comparative investigations of different types of metal oxide particles, their corresponding nanofluids, and their application in tribological tests to assess their usability as MQL-cutting fluids in machining is still in research. The technical application of those fluids is hindered by the lack of combined knowledge regarding the physical-chemical properties and their corresponding behavior as cutting fluids. Therefore, in this research, Al2O3, ZrO2 and TiO2 nanoparticles are added in different concentrations to base fluids to form water-glycerine-based nanofluids. The fluids were investigated regarding their physical-chemical properties such as particle distribution and viscosity and applied in tribological experiments to elaborate wear and particle deposition on steel workpieces. The influence of physical-chemical properties on the corresponding surfaces after tribological treatment was evaluated by scanning electron microscope imaging of the processed specimen. By varying the water-in-glycerine concentration, the often neglected viscosity increase of base fluid to mixed fluid was considered revealing a stronger influence of particle presence compared to viscosity increase caused by nanoparticle addition.

Bifunctional Catalysts with Core–Shell Distributed ZrO2 and Co Nanoparticles Derived from MOF-on-MOF Heterostructures for Economical One-Pot Tandem CO2 Fixation

The N-formylation of aryl amines with CO2 is an emerging strategy to simultaneously reduce carbon emission and produce high-value formamides. Considering that aryl amines are usually produced from the hydrogenation of their corresponding nitroarenes in the chemical industry, the one-pot tandem hydrogenation–formylation of nitroarenes with CO2 to formamides is obviously a much more economical but still unexploited strategy for efficient CO2 fixation. Herein, we report the rational synthesis of bifunctional catalysts with core–shell distributed ZrO2 and Co nanoparticles (NPs) from the controlled pyrolysis of a ZIF-67-on-UiO-66 heterostructure for this one-pot tandem reaction. To fabricate such MOF-on-MOF heterostructures, we develop a facile surfactant-assisted strategy to seed ZIF-8 nuclei on the UiO-66 surface, followed by the successful growth of a thickness-controlled ZIF-67 shell on the UIO-66 core. Based on further pyrolysis, the highly mesoporous derivants with core–shell distributed ZrO2 and Co NPs can be obtained, of which the reductive Co and Lewis basic ZrO2 can serve as highly active sites for the hydrogenation of nitroarenes and the N-formylation of aryl amines with CO2, respectively, due to their favorable electronic structures and good mass diffusion of reactants/intermediates. Impressively, the optimized core–shell catalyst achieves a much higher yield of N-(4-methoxyphenyl)formamide (99.5%) than its ZrO2/C (0%), Co-NC (14.1%), and physically mixed counterparts (52.3%) for the one-pot tandem hydrogenation–formylation between 4-nitroanisole and CO2 with good recyclability and a broad substrate scope, shedding light on the rational design of efficient bifunctional catalysts for this tandem CO2 fixation reaction.

The efficacy of reinforcement of glass fibers and ZrO2 nanoparticles on the mechanical properties of autopolymerizing provisional restorations (PMMA)

Objectiveto investigate and compare the reinforcing effects of glass fibers (GFs) and ZrO2 nanoparticles at different ratios on the Flexural Strength (FS), Microhardness (MH), and Surface Roughness (SR) of autopolymerizing provisional PMMA. MethodsA total of one hundred and twenty specimens of autopolymerizing PMMA were prepared for FS, MH, and SR tests and grouped as follows: no additives (control group), for the tested groups, different ratios of GFs and ZrO2 at 5% of autopolymerizing PMMA were incorporated. The ratios of GFs/ZrO2 nanoparticles were 0%-5%, 1%-4%, 2%-3%, 2.5%-2.5%, 3%-2%, 4%-1% and 5%-0% (n = 5). The FS was evaluated using the three-point bending test, MH was evaluated using the Vickers microhardness tester and SR was evaluated using a contact-type profilometer. Data were analyzed using ANOVA, Tukey’s test, and Person correlation at 0.05 level of significance. ResultsThe unreinforced group had the lowest FS, MH, and SR mean values followed by (0%GFs + 5% ZrO2), (1% GFs + 4% ZrO2), (2% GFs + 3% ZrO2), (2.5% GFs + 2.5% ZrO2), (3% GFs + 2% ZrO2), (4% GFs + 1% ZrO2) and (5% GFs + 0% ZrO2) which had the highest values. ConclusionHybrid reinforcement with GFs, ZrO2 nanoparticles, or a combination of them effectively improved flexural strength and microhardness of autopolymerizing provisional PMMA that would create provisional restorations with extended clinical service. GFs demonstrated superior reinforcing effects compared to ZrO2 nanoparticles. However, reinforcement with 2.5–5% GFs increased the surface roughness for provisional restoration.

Tribological, microhardness and color stability properties of a heat-cured acrylic resin denture base after reinforcement with different types of nanofiller particles.

Polymethyl methacrylate (PMMA) is not an ideal material in all aspects, as it has poor mechanical and antimicrobial properties. The enhancement of the mechanical and physical features of PMMA-based material is highly required. The present study aimed to estimate the effect of adding different types of nanoparticle (NP) materials on the mechanical and physical features of heat-cured acrylic resin denture base material. A total of 120 samples were divided into 4 groups: the control group; the 5 wt% ZrO2 NPs group; the 5 wt% TiO2 NPs group; and the 5 wt% Ag NPs group. Each one was subdivided into 3 groups according to the test performed: the microhardness test; the abrasive wear test; and the color stability test. Then, the results of these tests were evaluated. The maximum mean value for the microhardness test was observed in the group treated with the addition of 5 wt% Ag NPs, followed by the 5 wt% ZrO2 NPs group, and finally the 5 wt% TiO2 NPs group. The lowest mean microhardness value was recorded for the control group. The maximum mean value for the abrasive wear test was attributed to the control group and the lowest mean value was related to the 5 wt% Ag NPs group. The maximum color change was noted in the 5 wt% Ag NPs group, followed by the 5 wt% ZrO2 NPs and 5 wt% TiO2 NPs groups. The lowest mean value for the color change was found in the control group. There was an increase in hardness and wear resistance in the group treated by adding 5 wt% Ag NPs, and the control group had the best color stability, followed by the 5 wt% TiO2 NPs group. However, a detrimental effect on color stability was observed when 5 wt% Ag NPs was added.

Effect of sodium dodecyl sulfate surfactant on the surface properties of electroless NiP-TiO2-ZrO2 composite coatings on magnesium AZ91D substrate

This research incorporated nano TiO2 and ZrO2 particles into the NiP electroless bath to produce NiP-TiO2-ZrO2 composite deposits on magnesium AZ91D substrates. The impact of sodium dodecyl sulfate (SDS) (anionic surfactant) was utilized for deposition to minimize the agglomeration and clustering of particles in the electroless bath. Surface properties such as atomic force microscopy, energy dispersive X-Ray analysis, scanning electron microscopy, and X-ray diffraction are used to evaluate the surface morphologies of coating, surface roughness, elementary composition, and crystalline structure of the deposits. Furthermore, the impact of SDS surfactant on the corrosion properties of deposits was also studied using potentiodynamic polarization in a 5 wt% NaCl solution. The overall results reveal that incorporating anionic surfactant SDS at the optimum concentration of 1.5 g/L (CMC value) improved wettability, deposition rate, and surface roughness compared to the deposits developed without surfactant. The proposed mechanism is that the molecules of SDS surfactant could come into contact with the surface of NiP-TiO2-ZrO2 composite coating in the bath, increasing nanoparticle dispersion and resulting in a uniform coating. Furthermore, the electrochemical results show improved corrosion protection efficiency (PE%) of NiP-TiO2-ZrO2 composite coatings by increasing the concentration of SDS surfactant, achieving ∼87.9% at (1.5 g/L) CMC value.

Characterization and Superhydrophobic Anticorrosive Coating of AA-7475/ZrO2/Polymer Nanocomposites

An AA-7475 is coated with superhydrophobic (SH) polymer nanocomposites (PNCs), emphasizing the coating’s manufacturing, characterization, and anticorrosive qualities. Coating AA-7475 alloy with polyvinyl chloride (PVC), copper stearate (CS), and zirconium oxide (ZrO2) nanoparticles produces the desired superhydrophobic. Using an X-ray diffractometer, field-emission scanning electron microscopy, Fourier-transform infrared spectrometer, ZrO2 nanoparticles, CS, and PVC PNCs are analyzed structurally and molecularly. The atomic force microscope picture was analyzed to determine how the surface roughness affected the SH behavior reached by changing the weight percentage of ZrO2 nanoparticles from 0.6 to 3.0 wt%. PNC-5 with 3.0 wt% ZrO2 nanoparticles is used as resistance to corrosion coating for AA-7475 due to its water contact angle of 154°. In a 3.5% NaCl solution, uncoated and PNC-5-coated AA-7475 are examined using potentiodynamic polarization and electrochemical spectroscopy. PNC-5 coating reduces AA-7475 corrosion rate from 23.75 to 0.2253 mpy. In this study, we use polarization resistance, corrosion resistance efficiency, double layer capacitance, corrosion current density, and charge transfer resistance to demonstrate that the SH surface air trapping phenomena are responsible for effective corrosion resistance.

5Y–ZrO2 NPs with high dispersity and excellent sintering performance prepared by a novel sol-gel-flux method in the NaCl system

Herein, to alleviate the hard agglomeration of ZrO2 nanoparticles (NPs) fabricated by the traditional sol-gel method (SGM), a novel sol-gel-flux method (SGFM) is applied to tailor ZrO2 nanoparticles (NPs) stabilized by 5 mol% Y2O3 (5Y–ZrO2) by in situ introduction of NaCl NPs among xerogel particles. The phase composition, micromorphology, surface area, and sintering performances of 5Y–ZrO2 products fabricated by SGM and SGFM are compared. The effects of calcination temperature on the phase composition, micromorphology, and particle size of 5Y–ZrO2 products prepared by SGFM are systematically investigated. The results show that the 5Y–ZrO2 particles prepared by SGM are severely agglomerated and irregular, while the 5Y–ZrO2 NPs prepared by SGFM are well dispersed, uniformly distributed, and quasispherical. The former can hardly be densified by sintering, while the latter shows excellent sintering performance. By sintering 5Y–ZrO2 NPs prepared by SGFM at 1200 °C for 3 h, 5Y-TZP with a high density and an average grain size of 0.29 μm is fabricated. The in situ generated NaCl particles effectively separate ZrO2 particles during sintering. The calcination temperature plays a crucial role in controlling the phase composition, agglomeration degree, micromorphology, particle size distribution, and particle size of 5Y–ZrO2 products synthesized by SGFM, and the optimal calcination temperature is suggested to be 790 °C.

Tribological Properties of Nano-ZrO2 and PEEK Reinforced PTFE Composites Based on Molecular Dynamics

Polytetrafluoroethylene (PTFE) is a polymeric material with excellent self-lubricating properties. In this study, in order to improve the wear resistance of PTFE, the PTFE matrix was filled with soft-phase polyetheretherketone (PEEK) particles and hard-phase nano-ZrO2 particles in varying volume ratios. A linear reciprocating friction tester was used to test the tribological properties of the PTFE composites. Optical microscopy (OM) and scanning electron microscopy (SEM) were utilized to observe the formation and evolution of the transfer film on the surface of the counterpart metal during the friction process. Molecular dynamics simulation software (Materials Studio MS) was used to simulate and analyze the frictional behavior between the molecular structures of PTFE composites and the counterpart iron atoms on a microscopic scale. The results showed that the uniformity and firmness of the transfer film had an important influence on the wear resistance of the material. PEEK and ZrO2 nanoparticles were able to improve the firmness and formation rate of the transfer film, respectively, resulting in significant improvement in the wear resistance of PTFE (volume wear rate reduced from 7.7 × 10−4 mm3/Nm for pure PTFE to 1.76 × 10−6 mm3/Nm for nano-ZrO2/PEEK/PTFE). Molecular dynamics simulations revealed that the poor wear resistance of PTFE was due to significant interlayer slippage within its molecular chains. PEEK molecular chains could effectively adsorb PTFE molecular chains and formed a strong bond. ZrO2 nanoparticles also contributed to the overall stability of the PTFE matrix. Both soft and hard fillers significantly inhibited interlayer slippage between PTFE molecular chains, enhancing the shear deformation resistance of the material and thus improving the wear resistance of PTFE composites.

CFD-PBM Simulation for Continuous Hydrothermal Flow Synthesis of Zirconia Nanoparticles in a Confined Impinging Jet Reactor.

Computational fluid dynamics (CFD) and population balance models (PBM) were coupled together for the first time to simulate the synthesis of zirconia nanoparticles in a continuous hydrothermal flow synthesis (CHFS) system with a self-designed confined impinging jet mixing (CJM) reactor. The hydrodynamic and thermodynamic behaviors within the CJM reactor strongly influenced the formation of the ZrO2 nanoparticles. Crucial parameters, such as velocities, temperatures, mixing conditions, and reaction rates, were analyzed under various supercritical conditions. Temperature and velocity measurements as functions of distance were also investigated. Normal particle size distribution (PSD) patterns were observed in all cases. The mean particle sizes in this study were calculated and compared using PBM aggregation analysis.

Free-standing graphene/polyetherimide/ZrO2 porous interlayer to enhance lithium-ion transport and polysulfide interception for lithium-sulfur batteries

Attributing to high theoretical specific capacity and energy density, lithium-sulfur batteries (LSBs) are receiving great attention. However, the commercialization of such technology is seriously hindered by the shuttle effect of polysulfides during the round-trip charge and discharge process. Herein, with three types of carbon materials and ZrO2 nanoparticles filled in polyetherimide (PEI) support framework with good stability, porous composite films were obtained by a simple non-solvent phase separation (NIPS) as free-standing interlayers for LSBs. The obtained interlayers can not only provide hierarchical channels for improving lithium-ion transfer number, but also own excellent physicochemical stability and strong adsorption capability towards lithium polysulfide (LiPS). Compared with the pristine one, the representative LSB with graphene/polyetherimide/ZrO2 interlayer (GPZ) shows good initial cycle discharge specific capacity (1280 mAh g−1), better capacity retention (749 mAh g−1 after 200 cycles) and good rate performance (580 mAh g−1 at 2C). This work provides a facile and promising way to achieve functional interlayer with high stability for high performance LSBs.

Electrochemical Corrosion Potential Abatement of 304 Stainless Steel Coated with ZrO2 Nanoparticles under Boiling Water Reactor Operation Conditions

Electrochemical Corrosion Potential Abatement of 304 Stainless Steel Coated with ZrO2 Nanoparticles under Boiling Water Reactor Operation Conditions

Radiolysis of water at the surface of ZrO2 nanoparticles

Radiolysis of water at the surface of ZrO2 nanoparticles was investigated by measuring the production of radiolysis products from nanoparticle/water mixtures under irradiation. A pulse radiolysis study and a gamma radiolysis study were conducted to observe and quantify radiolytically generated hydrated electrons (e-aq) and H2 from ZrO2/water mixtures. The radiolytic yield of e-aq and H2 from ZrO2 nanoparticles (20–5000 nm in diameter) was found to increase with increasing nanoparticle surface area indicating surface enhanced radiolysis. This was attributed to radiolysis of surface adsorbed water molecules. The thickness of the surface adjacent water layer was shown to affect radiolysis, with smaller numbers of water layers increasing radiolysis.

Dispersion control via crystal-phase modulation of yttrium-doped ZrO2 nanoparticle sol

Improved dispersibility of zirconia nanoparticles (ZrO2 NPs) is crucial in many optical applications, but traditional dispersion methods using dispersants or devices can be problematic. In this study, we propose a simple and novel dispersion method that controls the crystalline phase through yttrium (Y3+) doping to improve dispersibility. The ZrO2 NPs colloidal sol was developed using three precursors – acetate-based zirconia (A-ZrO2), acetate-based 3-yttria stabilized zirconia (A-3YSZ), and chloride-based 3-yttria stabilized zirconia (C-3YSZ). The A-3YSZ exhibited the most superior dispersibility among the samples due to its low surface energy. Furthermore, it maintained dispersibility even though precursor concentration increased up to 6 wt%. Our results show that A-3YSZ is an effective inorganic filler for improving the refractive index of an acrylate-based coating solution. This is due to its excellent dispersibility and simple synthesis without requiring additional chemical modification and complicated dispersion processes.