ZrW2O8 Research Articles

Investigation on preparation and properties of gel type 188W/188Re generator

As one of the most important integrated nuclides for diagnosis and treatment in recent years, rhenium-188 (188Re) has a broad scope in the clinical application. Due to the specific properties of such radionuclide, it was mainly provided by the chromatographic 188W-188Re generators. There is no doubt that the application of 188Re in the treatment of various diseases depended on the development of 188W-188Re generator. Considering the high standards of such technology on radioactive activity of 188W and impurity content, a 188W-188Re generator filled with the zirconium tungstate gel has been prepared in this work. The effects of molar ratio of chemical agents, pH, reaction temperature, drying methods, rinsing methods and other conditions on the synthesis of gel particles have been studied. Furthermore, a variety of characterization techniques were used to observe the macro-/micro-morphology and chemical structure of gel particles. It can be concluded that vacuum freeze-dried method could significantly increase the specific surface area, pore size and tungsten content of gel particle. In order to decrease the content of 188W in the elute, a handful of acidic alumina was filled in the bottom of our 188W-188Re generator, an elution and purification integrated-generator was formed. During the first five processes, the nuclear purity of 188Re solution was above 99.99%, the radiochemical purity was approximately 99.5%, the pH value was 5.0–7.0 and the average elution efficiency reached up to 82.7%. In addition, the leakage rate of 188W was low as 1.60 × 10−6, and the peak of elute curve was located at 2 mL without the trailing phenomenon. This work lays a solid foundation for the domestic demand of daughter nuclide 188Re, further makes an outstanding contribution to the application of the radiation therapy technology and the protection of people's health.

Synthesis and Characterization of Low-Cost Zirconium Nanocomposites as Novel Adsorbents for Arsenazo III Pollutant

Removing contaminated Arsenazo III dye from contaminated effluent is a challenge and of great interest due to its hazard and environmental impact. Therefore, the biggest challenge was producing highly efficient, easy to recycle, and economically inexpensive adsorbent materials for the contaminated dye. Three chemically stable zirconium nanocomposites with unique properties were synthesized by gel-precipitation technology. The composition, chemical, and physical properties of zirconium molybdate, tungstate, and silicate nanocomposites have been extensively proven using many different and appropriate devices such as XRD, SEM–EDX, TEM, FT-IR, BET, DLS, TGA-DTA, and zeta potential. By utilizing the most effective adsorption techniques, Azo-dye was successfully bound to ZrMo-NPs, ZrW-NPs, and ZrSi-NPs composites. The uptake capacities for these composites were measured at 0.29, 0.79, and 1.61 mmol.g−1, respectively. The sorption parameters were optimized as follows: a feed solution pH of 3 for ZrMo-NPs, a pH of 2.3 for ZrW-NPs, and a pH of 2.3 for ZrSi-NPs. The stirring time was set at 30 min, the metal ion concentration was 1.64 mmol L−1, and the sorbent dose was 7.5 mg. The adsorption results agreed well with the Langmuir isotherm and the pseudo-second-order reaction models and demonstrated the endothermic nature and kinetic improvement by increasing temperatures. The three nanocomposites effectively eliminated tainted dye from lab wastewater, offering promise for their potential applications in the future.Graphical

Structure and tribological behavior of a polyetherimide/polytetrafluoroethylene matrix filled with negative thermal expansion zirconium tungstate particles

Thermal expansion mismatch stresses may be a reason for premature failure of sealing and bearing components made of polymer composites that are rubbed against metallic surfaces at elevated temperatures. It is of particular importance for polymer matrix composites loaded with anti-friction inclusions of polytetrafluoroethylene (PTFE) that possesses high coefficient of thermal expansion. In this regard, a study was undertaken to elucidate the effect of the thermal mismatch on wear and friction of amorphous polyetherimide (PEI) matrix loaded with either polytetrafluoroethylene (PTFE) particles (i) or PTFE particles covered with negative thermal expansion zirconium tungstate (ZT) α-ZrW2O8 (ii) at temperatures 23 °C, 120 °C and 180 °C. The ball-on-disk testing scheme was used according to standard with AISI 52100 steel balls rubbed against a polymer composite disks at normal force P = 5 N and sliding velocity V = 0.3 m/s. The PEI/PTFE/ZT composite demonstrated a tendency for wear rate (WR) reduction in sliding at 120 °C and 180 °C as compared to corresponding WR enhancement on the PEI/PTFE. The rationale is provided that the ZT additive effectively reduced thermal expansion of the PTFE in the PEI matrix and thus improved wear resistance of the composite. New thermal expansion-controlled wear and friction instability mechanism has been proposed and discussed.

The effect of carbon fiber length on the thermal expansion of fiber‐reinforced particulate hybrid composites

AbstractThermal expansion of materials is a critical factor influencing their dimensional stability. This study explores the regulation of thermal expansion in composite materials through the incorporation of carbon fibers and zirconium tungstate particles. The influence of fiber length on the thermal expansion behavior of these composites was investigated. The investigation reveal that the variation in the relative elongation ratio (dl/L0) of the carbon fiber‐reinforced zirconium tungstate composites is nonlinear, characterized by an initial increase, subsequent decrease, and a final resurgence. Notably, an increase in fiber length results in a mitigated rate of increase in the (dl/L0) ratio. Furthermore, composites fabricated with shorter fibers exhibit a higher coefficient of thermal expansion (CTE). Upon elevating the temperature to 250°C, the CTE for composites reinforced with 100 and 500 mesh carbon fibers escalate to 24.5 × 10−6/K and 74.6 × 10−6/K, respectively. These values represent an 8% and 116% enhancement relative to those measured at 50°C.Highlights The thermal expansion properties are improved by adding carbon fiber and ZrW2O8 nanoparticles. Utilizing fiber lengths ranging from 100 to 500 mesh effectively diminishes the CTE. The Cf‐ZrW2O8/9621 composite exhibits non‐linear behavior in its dl/L0 ratio. Within the range, longer fibers are more beneficial for reducing the CTE.

Zirconium tungstate (Zr4W8O32)-doped zirconium dioxide (ZrO2) for gamma ray shielding: an in-depth examination of fabrication, characterizations, and gamma ray attenuation properties

Zirconium tungstate (Zr4W8O32)-doped zirconium dioxide (ZrO2) for gamma ray shielding: an in-depth examination of fabrication, characterizations, and gamma ray attenuation properties

Heterogeneous H2O2-based selective oxidations over zirconium tungstate α-ZrW2O8.

Catalytic properties of a crystalline zirconium tungstate, ZrW2O8, the material known mainly for its isotropic negative coefficient of thermal expansion, have been assessed for the liquid-phase selective oxidation of a range of organic substrates comprising CC, OH, S and other functional groups using aqueous hydrogen peroxide as the green oxidant. Samples of ZrW2O8 were prepared by hydrothermal synthesis and characterised by N2 adsorption, PXRD, SEM, EDX, FTIR and Raman spectroscopic techniques. Studies by IR spectroscopy of adsorbed probe molecules (CO and CDCl3) revealed the presence of Brønsted acidic and basic sites on the surface of ZrW2O8. It was demonstrated that ZrW2O8 is able to activate H2O2 under mild conditions and accomplish the epoxidation of CC bonds in alkenes and unsaturated ketones, oxidation of thioethers to sulfoxides and sulfones, along with the oxidation of alcoholic functions to produce ketones and aldehydes. The oxidation of tetramethylethylene and α-terpinene over ZrW2O8 revealed the formation of peroxidation products, 2,3-dimethyl-3-butene-2-hydroperoxide and endoperoxide ascaridole, respectively, indicating the involvement of singlet oxygen in the oxidation process. The ZrW2O8 catalyst preserves its structure and morphology under the turnover conditions and does not suffer from metal leaching. It can be easily recovered, regenerated by calcination, and reused without the loss of activity and selectivity.

Preparation of fluorinated poly(aryl ether) with high dimensional stability and high temperature resistance by photo‐thermal dual crosslinking reaction

AbstractImproving the dimensional stability is significant for fluorinated poly(aryl ether) (FPAE). In this work, zirconium tungstate (ZrW2O8) with negative thermal expansion (NTE) modified by thiol groups is successfully obtained by surface modification with 3‐(trimethoxysilyl)‐1‐propanethiol. Then, the dispersion of ZrW2O8 is improved and a certain crosslinked structure is formed by click reaction between thiols on the surface of ZrW2O8 and allyl groups on the backbone of FPAE. On this basis, the residual allyl groups on the FPAE can undergo addition reaction under heating conditions to further form crosslinked structure. Due to the introduction of photo‐thermal dual crosslinked structure, the dimensional stability of FPAE is significantly improved, and the coefficient of thermal expansion decreased by 64.3% compared to the unoptimized samples. Meanwhile, the dielectric properties are characterized with dielectric constant and dissipation factor of 3.70 and 0.008 at 1 kHz. Finally, the prepared film is used to assemble triboelectric nanogenerators, where the short‐circuit current, open‐circuit voltage and transferred charge is 3 μA, 30 V, and 10 nC, respectively. Crosslinked FPAE with high dimensional stability and high temperature resistance are successfully gained by avoiding the complexity of monomer synthesis and realizing higher performance with the same inorganic filler loading.Highlights Dual crosslinked structure is built by photo‐thermal dual crosslinking reaction. ZrW2O8 gains homogeneous dispersion in polymer matrix by photo‐crosslinking reaction. Introducing ZrW2O8 and dual crosslinked structure raises dimensional stability of film.

Construction of zirconium tungstate modified polymer bonded energetic composites with highly inhibited thermal expansion via bioinspired interfacial reinforcement

Precise dimension control during the thermal cycle by introducing negative thermal expansion (NTE) nano-fillers is attractive and highly challenging for polymer bonded energetic composites. Achieving the ability to obtain homogeneous dispersion of NTE nanoparticles and tailoring the interface are the keys to realising desirable thermal expansion performances in the energetic composites. Inspired by the strong chemical adhesion of mussels, we reported a general strategy to coat NTE nanoparticles (i.e., zirconium tungstate, ZrW2O8) with dopamine through a simple immersion method. Polydopamine (PDA) coating can effectively improve the dispersion of ZrW2O8 and enhance the interaction between the ZrW2O8 nanoparticles and polymer binder matrix. The ZrW2O8@PDA (pZrW2O8) based energetic composites exhibited significantly suppressed thermal expansion, greatly enhanced thermal stability of microstructures, and mechanical properties in comparison with the corresponding composites modified with raw ZrW2O8. Our strategy provides a facile pathway to achieve high-performance energetic composites with high thermal stability.

Luminescence investigations of hydrothermally synthesized terbium doped zirconium tungstate nanorods

Rare-earth based phosphors play a key role in enhancing the quality of the phosphor converted LEDs (pc-LEDs). But the creation of phosphors with high thermal stability is still a task. This work aims to investigate the luminescence properties of ZrW2O8, which is known to have a negative or almost zero coefficient of thermal expansion. ZrW2O8 doped with Tb3+ is optimized by the conventional hydrothermal method in acidic medium. The PXRD analysis confirms the crystallization of the material into high purity cubic phase to the P213 space group. The tungstate group's distinctive vibrational modes were identified by FTIR analysis. TGA analysis demonstrates the remarkable thermal stability of the material over a wide temperature range. The preferential growth along one direction to form distinct nanorods was investigated using TEM. The optical band gap is found to increase after doping. The high and broad charge transfer band at 284 nm in the excitation spectra is an indication of the efficient energy transfer from the host to Tb3+ ions and the possibility of NUV excitation. The characteristic green emission peak of the Tb3+ at 543 nm and the values of the CCT and CP obtained using the colorimetry study suggest that the obtained material can be used as a green component to produce cold white LEDs.

Mitigating cryogenic microcracking in carbon-fibre reinforced polymer composites using negative thermal-expansion nanoparticles functionalized by a polydopamine coating

Herein, we report a new method of mitigating cryogenic microcracking in carbon-fibre reinforced-plastics (CFRPs) using a negative thermal-expansion nanomaterial, zirconium tungstate (ZrW2O8), to simultaneously reduce the thermal residual stresses and enhance the fracture energy of the epoxy matrix of CFRPs. The results show that 1 wt% of added ZrW2O8 nanoparticles functionalized by polydopamine can increase the fracture energy of the matrix material by 140%, reduce the coefficient of thermal expansion by 20% and, more importantly, enhance the interlaminar fracture energy of the resulting CFRP by about 100% at −196 °C. The ZrW2O8-modified matrix has been demonstrated to successfully prevent microcracking at −196 °C in a blocked cross-ply CFRP laminate with a [04/908/04] fibre architecture.

Zirconium tungstate reinforced energetic composites with inhibited thermal expansion and reduced thermal stress

Due to their large positive thermal expansion property, polymer bonded explosives (PBXs) are prone to deform under environmental temperature cycle. Based on the volume compensation effect, zirconium tungstate (ZrW2O8) with a negative thermal expansion (NTE) characteristic was first introduced to tailor the thermal expansion of energetic composites in this work. The PBXs modified with ZrW2O8 were fabricated by non-water kneading granulation technique, and their thermal expansion, mechanical properties, as well as microstructural thermal stability were systematically investigated. The coefficient of thermal expansion (CTE) during the heating stage and the strain were reduced by 19.8% and 19.1% for modified PBXs with the incorporation of 10 wt% ZrW2O8. For ZrW2O8 filled energetic composites at lower filler loading (≤10 wt%), the experimental values fell in between the Turner’s model and Schapery’s lower boundaries. Numerical simulation revealed that the decreased CTE could reduce thermal stress, which would benefit the safety and reliability of the weapon system. Combined with thermal and mechanical analyses, the thermal shock resistance of the ZrW2O8 modified energetic composite with 10 wt% filler loading was found to be 45% higher than that of pristine PBX without ZrW2O8, suggesting a reinforcement effect, which would be helpful for long-term storage of materials under environmental temperature cycles. The successful application of this functional NTE system to energetic materials might provide a new strategy for the construction of novel energetic composites with tailored thermal expansion.

In-Situ Al-Mg Alloy Base Composite Reinforced by Oxides and Intermetallic Compounds Resulted from Decomposition of ZrW2O8 during Multipass Friction Stir Processing.

In the presented work, the effect of friction stir processing admixing the zirconium tungstate ZrW2O8 powder on the microstructure, mechanical and tribological properties of the AA5056 Al-Mg alloy stir zone has been studied. The FSP resulted in obtaining dense composite stir zones where α-ZrW2O8 underwent the following changes: (i) high-temperature transformation into metastable β'-ZrW2O8 and (ii) decomposition into WO3 and ZrO2 oxides followed by the formation of intermetallic compounds WAl12 and ZrAl3. These precipitates served as reinforcing phases to improve mechanical and tribological characteristics of the obtained fine-grained composites. The reduced values of wear rate and friction coefficient are due to the combined action the Hall-Petch mechanism and reinforcement by the decomposition products, including Al2O3, ZrO2, β'-ZrW2O8 and intermetallic compounds such as WAl12 and ZrAl3. Potential applications of the above-discussed composites maybe related to their improved tribological characteristics, for example in aerospace and vehicle-building industries.

Origin of negative thermal expansion and pressure-induced amorphization in zirconium tungstate from a machine-learning potential

Understanding various macroscopic pressure-volume-temperature properties of materials on the atomistic level has always been an ambition for physicists and material scientists. Particularly, some materials such as zirconium tungstate (ZrW2O8), exhibit multiple exotic properties including negative thermal expansion (NTE) and pressure-induced amorphization (PIA). Here, using machine-learning based deep potential, we trace both of the phenomena in ZrW2O8 back to a common atomistic origin, where the nonbridging O atoms play a critical role. We demonstrate that the nonbridging O atoms confer great flexibility to vibration of polyhedrons, and kinetically drive volume shrinking on heating, or NTE. In addition, beyond a certain critical pressure, we find that the migration of nonbridging O atoms leads to additional bond formation that lowers the potential energy, suggesting that the PIA is a potential-driven first-order phase transition. Most importantly, we identify a second critical pressure beyond which the amorphous phase of ZrW2O8 undergoes a hidden phase transition from a reversible phase to an irreversible one.

Facile synthesis of platelet‐like zirconium tungstate nanostructures for high‐performance supercapacitors

Increasing demand for electronic devices has sparked quantum of research work on energy storage systems. In the present work, we report the facile synthesis of platelet-like Zirconium tungstate (ZrW2O8 NPs) binary metal oxide via co-precipitation method. The ZrW2O8 NPs was confirmed by several physicochemical techniques. Furthermore, FESEM images proved the platelet-like morphology of ZrW2O8 NPs. The as-prepared ZrW2O8 NPs was used as electrode material in the fabrication of supercapacitors. ZrW2O8 NPs @ Ni foil shows the specific capacitance (Csp) maximum of 508 F g−1 at 5 mV/s and showed 91.3% of cyclic stability after 4000 GCD cycles. As a result, ZrW2O8 NPs was utilized as an anode electrode material to construct an asymmetric device, ZrW2O8 NPs || Activated carbon (AC). The as-fabricated device showed the energy density of 9.65 Wh kg−1 related to the power density of 299.48 W kg−1. The effective supercapacitive behavior might be due to the unique morphological features, occurrence of multiple redox sites, and enhanced electrical conductivity of ZrW2O8 NPs. Thus, all these findings account for the applicability of ZrW2O8 NPs as electrode material in high-performance supercapacitors.

Zirconium Tungstate Reinforced Energetic Composites with Inhibited Thermal Expansion and Reduced Thermal Stress

Zirconium Tungstate Reinforced Energetic Composites with Inhibited Thermal Expansion and Reduced Thermal Stress

Enhanced Electrochemical Performance of LiNi0.6Co0.2Mn0.2O2 by a Negative‐Thermal‐Expansion Material at Elevated Temperature

More measures are being developed to enhance the electrochemical stability of single‐crystal LiNi0.6Co0.2Mn0.2O2 (NCM622), but few focus on improving the stability of NCM622 through heat and deformation management. Herein, a negative‐thermal‐expansion (NTE) material of zirconium tungstate ZrW2O8 is adopted to modify NCM622 via a facile method, and the sample with a proper content of ZrW2O8 exhibits superior cycle performance and rate capability. The capacity retention ratio of modified NCM622 is 86.2% (from 193.6 to 166.8 mAh g−1) after 100 cycles at 2 C between 2.8 and 4.5 V at 60 °C, whereas that of the pristine NCM622 is only 77.5% (from 183.8 to 142.4 mAh g−1). According to various analysis results, the possible enhancing mechanisms of ZrW2O8 for NCM622 are discussed. It is an alternative for the remaining good structure of energy materials using NTE materials.

Adsorptional-photocatalytic removal of fast sulphon black dye by using chitin-cl-poly(itaconic acid-co-acrylamide)/zirconium tungstate nanocomposite hydrogel

In the present work, the removal of fast sulphon black (FSB) dye from water was executed by using chitin-cl-poly(itaconic acid-co-acrylamide)/zirconium tungstate nanocomposite hydrogel (Ch-cl-poly(IA-co-AAm)-ZrW NCH). The Ch-cl-poly(IA-co-AAm)-ZrW NCH was fabricated proficiently by microwave-induced sol-gel/copolymrization method. The zirconium tungstate (ZrW) photocatalyst was prepared by co-precipitation method using sodium tungstate and zirconium oxychloride in ratio (2:1). The polymeric hydrogel part has been used to support the ZrW, and it acted as an adsorbent for adsorptive removal of FSB dye. The band gap for nanocomposite hydrogel was found about 4.18 eV by using Tauc equation. The Ch-cl-poly(IA-co-AAm)-ZrW NCH was characterized by various techniques as FTIR (Fourier-transform infrared spectroscopy), X-ray diffraction (XRD), transmittance electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The adsorptional-photocatalytic remediation experiment of FSB dye was optimized for reaction parameters as FSB dye and Ch-cl-poly(IA-co-AAm)-ZrW NCH concentration, and pH. The maximum percentage removal for FSB dye was observed at 92.66% in 120 min under adsorptional-photocatalysis condition.

Fitting of interatomic potentials by a differential evolution algorithm

Computer simulation has been increasingly present in the discovery and understanding of materials structure and properties. First-principles simulations, in particular, allow to meaningfully explore the material world without having to resource to experimental methods. Even though their extreme usefulness, first-principle methods tend to be very computer-intensive to the point of being impractical in many situations that are important for the understanding of materials’ behavior. As an alternative, computer simulations can be carried out using interatomic potentials (IPs), in which case an analytic mathematical model for the energy of the system is fitted to a set of crystal structure parameters and experimentally determined physical properties by minimizing a cost function. How close the properties calculated using an IP can get of those experimentally determined is limited both by its analytic form and the model’s parameters. For compounds with different atomic species, the multidimensional parameter space of the cost function most possibly exhibit a very complex landscape. In these cases, global minimization methods are often required. This work explores the use of a differential evolution (DE) algorithm for the parametrization of IPs for two compounds, namely berlinite (AlPO4) and zirconium tungstate (α-ZrW2O8). Several analytic interatomic potentials (including some previously proposed in the literature) were fitted to experimental lattice parameters, atomic positions, and elastic constants. Two-dimensional mappings of the interatomic potential parameters reveal the complex landscape of the cost function for berlinite and α-ZrW8O8, which exhibits several local minima, broad plateaus, discontinuities, and, in some cases, strong correlations between fitting parameters. The differential evolution algorithm was able to navigate the cost function landscape and, giving a sufficiently large population, was capable to found good candidates for the global minimum, despite all the mentioned difficulties. In all cases here explored, the interatomic potentials re-parametrized using DE yield calculated athermal properties in better agreement with the experimental observables as compared to previous results from the literature.

Structural, Fatigue Behavior, and Mechanical Properties of Zirconium Tungstate-Reinforced Casted A356 Aluminum Alloy

The aim of this study is to investigate the structure–property relationship of the zirconium tungstate-reinforced casted A356 aluminum alloy. The reinforcement ceramic used was zirconium tungstate of the negative thermal coefficient type, which assists in the weldment of crack growth and enhances the fatigue life. The specimens used in this study were casted by stir casting method and prepared according to Compact Tension standard E-399, and microstructural, fatigue behavior, and mechanical properties were investigated systematically. Microstructural analysis showed reduction in porosity by the addition of ZrW2O8 particles. Fatigue results depict the increase in the fatigue life of aluminum reinforced ceramic as compared to the casted base aluminum alloy. Brinell hardness of ZrW2O8 reinforced alloy samples increased 7% as compared to the base aluminum alloy hardness value. Tensile strength also significantly improved from 176 MPa for the base A356 alloy to 198 MPa for the ZrW2O8 reinforced composite. Furthermore, addition of ZrW2O8 ceramic powder increased the fatigue life more than 50% of the base alloy. These results suggest that the ZrW2O8 reinforced A356 composites may be potential candidates for aerospace industry, military, transportation and in structural sites.

Experimental demonstration of lightweight lattice metamaterials with controllable low thermal expansion

Materials with customized thermal expansion, capable of avoiding thermal failure or distortion of structures and devices, are vital for aerospace, civil, biomedical, optics and semiconductor applications. The coefficient of thermal expansion (CTE) of natural materials usually is hard to be engineered and a negative CTE is still exceptional. Here, we have synthesized a polymer with low thermal expansion by blending Zirconium tungstate (ZrW2O8), and have experimentally demonstrated extremely low thermal expansion of 2D non-metallic bi-material Hoberman spherical lattice metamaterials, showing a metal-like CTE with 1.0 × 10−5 °C−1. The theoretical prediction is implemented to verify the tested CTE and unveil the underlying mechanisms responsible for this unusual behavior. The findings presented here have experimentally validated to design architected metamaterial systems with controllable low thermal expansion and having a wide range of potential applications.