Phase-field simulations of the effect of temperature and interface for zirconiumδ-hydrides

Hydride precipitation in zirconium cladding materials can damage their integrity and durability.Service temperature and material defects have a significant effect on the dynamic growth of hydrides.In this study,we have developed a phasefield model based on the assumption of elastic behaviour within a specific temperature range(613 K-653 K).This model allows us to study the influence of temperature and interfacial effects on the morphology,stress,and average growth rate of zirconium hydride.The results suggest that changes in temperature and interfacial energy influence the length-to-thickness ratio and average growth rate of the hydride morphology.The ultimate determinant of hydride orientation is the loss of interfacial coherency,primarily induced by interfacial dislocation defects and quantifiable by the mismatch degree q.An escalation in interfacial coherency loss leads to a transition of hydride growth from horizontal to vertical,accompanied by the onset of redirection behaviour.Interestingly,redirection occurs at a critical mismatch level,denoted as qc,and remains unaffected by variations in temperature and interfacial energy.However,this redirection leads to an increase in the maximum stress,which may influence the direction of hydride crack propagation.This research highlights the importance of interfacial coherency and provides valuable insights into the morphology and growth kinetics of hydrides in zirconium alloys.

Properties of radiation defects and threshold energy of displacement in zirconium hydride obtained by new deep-learning potential

Zirconium hydride(ZrH_(2)) is an ideal neutron moderator material. However, radiation effect significantly changes its properties, which affect its behavior and the lifespan of the reactor. The threshold energy of displacement is an important quantity of the number of radiation defects produced, which helps us to predict the evolution of radiation defects in ZrH_(2).Molecular dynamics(MD) and ab initio molecular dynamics(AIMD) are two main methods of calculating the threshold energy of displacement. The MD simulations with empirical potentials often cannot accurately depict the transitional states that lattice atoms must surpass to reach an interstitial state. Additionally, the AIMD method is unable to perform largescale calculation, which poses a computational challenge beyond the simulation range of density functional theory. Machine learning potentials are renowned for their high accuracy and efficiency, making them an increasingly preferred choice for molecular dynamics simulations. In this work, we develop an accurate potential energy model for the ZrH_(2) system by using the deep-potential(DP) method. The DP model has a high degree of agreement with first-principles calculations for the typical defect energy and mechanical properties of the ZrH_(2) system, including the basic bulk properties, formation energy of point defects, as well as diffusion behavior of hydrogen and zirconium. By integrating the DP model with Ziegler–Biersack–Littmark(ZBL) potential, we can predict the threshold energy of displacement of zirconium and hydrogen in ε-ZrH_(2).

Two-dimensional investigation of characteristic parameters and their gradients for the self-generated electric and magnetic fields of laser-induced zirconium plasma

Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic probes.The characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was established.The measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser irradiance.However,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the plume.However,the E and B fields were observed to be always diffusing away from the target.The radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number density.The higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and ions.The generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.

Electrochemical Analysis of Zirconiumin Aqueous and Organic Media

For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media was selected on the basis of the Pourbaix potential-pH diagram, which provides informations on the predominance of Zr(IV) ion and Zr in aqueous media. In aqueous media, analyzes were first carried out in acidic media then in basic media. Studies have thus revealed that the acidic environment is not favourable for the electrochemical analysis of zirconium. Voltammograms obtained in an acidic environment show no zirconium detection signal;this is due to the strong presence of H+ ions in the solution. We have also observed in acidic media the phenomenon of passivation of the electrode surface. In aqueous alkaline media (pH = 13), we have drawn in reduction several Intensity-Potential curves by fixingsome technical parameterslike scanning speed, rotation speed of the electrode. The obtained voltammograms show cathodic waves, starting from -1.5 V/DHW and attributed to the reduction of Zr (IV) to Zr (0). The last phase of this study focused on the electrochemical analysis of zirconium in an organic media. In this media, several intensity-potential curves were plotted in reduction and in cyclic voltammetry with various parameters. Through several reduction analysis, the Zr (IV) was reduced to Zr (0) to the potential of -1.5 V/DHW. The electrochemical analysis of zirconium in organic media seems globally easier to achieve thanks to its large solvent window (i.e. dimethylformamide (DMF) solvent window > 6 V).

One-step ethylene separation from ternary C_(2) hydrocarbon mixture with a robust zirconium metal-organic framework

One-step separation of high-purity ethylene(C_(2)H_(4))from C_(2) hydrocarbon mixture is critical but challenging because of the very similar molecular sizes and physical properties of C_(2)H_(4),ethane(C_(2)H_(6)),and acetylene(C_(2)H_(2)).Herein,we report a robust zirconium metal-organic framework(MOF)Zr-TCA(H3TCA=4,4',4"-tricarboxytriphenylamine)with suitable pore size(0.6 nm×0.7 nm)and pore environment for direct C_(2)H_(4) purification from C_(2)H_(4)/C_(2)H_(2)/C_(2)H_(6) gas-mixture.Computational studies indicate that the abundant oxygen atoms and non-polar phenyl rings created favorable pore environments for the preferential binding of C_(2)H_(2) and C_(2)H_(6) over C_(2)H_(4).As a result,Zr-TCA exhibits not only high C_(2)H_(6)(2.28 mmol·g^(-1))and C_(2)H_(2)(2.78 mmol·g^(-1))adsorption capacity but also excellent C_(2)H_(6)/C_(2)H_(4)(2.72)and C_(2)H_(2)/C_(2)H_(4)(5.64)selectivity,surpassing most of one-step C_(2)H_(4) purification MOF materials.Dynamic breakthrough experiments confirm that Zr-TCA can produce high-purity C_(2)H_(4)(>99.9%)from a ternary gas mixture(1/9/90 C_(2)H_(2)/C_(2)H_(6)/C_(2)H_(4))in a single step with a high C_(2)H_(4) productivity of 5.61 L·kg^(-1).

Biomimetic amelioration of zirconium nanoparticles on a rigid substrate over viscous slime--a physiological approach

In this article,an investigation is conducted to study the precise role of zirconium nanoparticles that exist in a slime-like fluid subject to specific adjustments.Since gliding is a technique of mobility used by bacteria that lack motility components,bacteria travel on their own strength in gliding locomotion by secreting a layer of slime on the substrate.A model of an undulating sheet over a layer of slime of a Rabinowitsch fluid is investigated as a potential model of bacteria’s gliding motility.With the aid of long wavelength approximation,the equations governing the circulation of slime underneath the cells are established and analytically solved.The effects of pseudoplasticity,dilatation and non-Newtonian parameter on the behavior of zirconium concentration,speed of microorganism(bacteria),streamline patterns,and pressure rise for non-Newtonian and Newtonian fluids are compared.The power required for propulsion is also investigated.Physical interpretation for the pertinent variables has been graphically discussed against the parameters under consideration.It is found that with the increase in the concentration of zirconium nanoparticles,the bacterial flow is accelerated and attains its maximum near the rigid substrate wall while an opposite behavior is noticed in the rest region.

Intercalation assisted liquid phase production of disulfide zirconium nanosheets for efficient electrocatalytic dinitrogen reduction to ammonia

Disulfide zirconium(ZrS_(2)) is a two-dimensional(2D) transition metal disulfide and has given rise to extensive attention because of its distinctive electronic structure and properties.However,mass production of high quality of ZrS_(2)nanosheets to realize their practical application remains a challenge.Here,we have successfully exfoliated the bulk ZrS_(2)powder with the thickness of micron into single and few-layer nanosheets through liquid-phase exfoliation in N-methylpyrrolidone(NMP) assisted via aliphatic amines as intercalators.It is found that the exfoliation yield is as high as 27.3%,which is the record value for the exfoliation of ZrS_(2)nanosheets from bulk ZrS_(2)powder,and 77.1% of ZrS_(2)nanosheets are 2-3 layers.The molecular geometric size and aliphatic amine basicity have important impact on the exfoliation.Furthermore,the ZrS_(2)nanosheets have been used as catalyst in the electrocatalytic dinitrogen reduction with the NH3yield of 57.75 μg h^(-1)mg_(cat.)^(-1),which is twice that by ZrS_(2)nanofibers reported in literature and three times that by the bulk ZrS_(2)powder.Therefore,the liquid phase exfoliation strategy reported here has great potential in mass production of ZrS_(2)nanosheets for high activity electrocatalysis.

Relations of Microstructural Attributes and Strength-Ductility of Zirconium Alloys with Hydrides

As the first safety barrier of nuclear reactors,zirconium alloy cladding tubes have attracted extensive attention because of its good mechanical properties.The strength and ductility of zirconium alloy are of great significance to the service process of cladding tubes,while brittle hydrides precipitate and thus deteriorate the overall performance.Based on the cohesive finite element method,the effects of cohesive strength,interfacial characteristics,and hydrides geometric characteristics on the strength and ductility of two-phase material(zirconium alloy with hydrides)are numerically simulated.The results show that the fracture behavior is significantly affected by the cohesive strength and that the overall strength and ductility are sensitive to the cohesive strength of the zirconium alloy.Furthermore,the interface is revealed to have prominent effects on the overall fracture behavior.When the cohesive strength and fracture energy of the interface are higher than those of the hydride phase,fracture initiates in the hydrides,which is consistent with the experimental phenomena.In addition,it is found that the number density and arrangement of hydrides play important roles in the overall strength and ductility.Our simulation provides theoretical support for the performance analysis of hydrogenated zirconium alloys during nuclear reactor operation.

Functional zirconium phosphate nanosheets enabled transfer hydrogenolysis of aromatic ether bonds over a low usage of Ru nanocatalysts

Catalytic hydrogenolysis of aromatic ether bonds is a highly promising strategy for upgrading lignin into small-molecule chemicals,which relies on developing innovative heterogeneous catalysts with high activity.Herein,we designed porous zirconium phosphate nanosheet-supported Ru nanocatalysts(Ru/ZrPsheet)as the heterogeneous catalyst by a process combining ball milling and molten-salt(KNO_(3)).Very interestingly,the fabricated Ru/ZrPsheetshowed good catalytic performance on the transfer hydrogenolysis of various types of aromatic ether bonds contained in lignin,i.e.,4-O-5,a-O-4,β-O-4,and aryl-O-CH3,over a low Ru usage(<0.5 mol%)without using any acidic/basic additive.Detailed investigations indicated that the properties of Ru and the support were indispensable.The excellent activity of Ru/ZZrPsheetoriginated from the strong acidity and basicity of ZrPsheetand the higher electron density of metallic Ru0as well as the nanosheet structure of ZrPsheet.

Incorporation of Nano-Zinc Oxide in Lamellar Zirconium Phosphate: Synthesis and Characterization

In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychloride octahydrate and phosphoric acid following its chemical modification with Jeffamine and nano-ZnO. Diffractometric, morphological, thermal, structural and relaxometric evaluations were conducted. Fourier transform infrared spectroscopy (FTIR) revealed increase of the area between 4000 - 3000 cm-1 due to the formation of ionic specie PO? +NH3-[C-(H)(CH3)-CH2-O-(C-(H)(CH3)-CH2-O)8-(CH2-CH2-O-CH3)] and nano-ZnO particles. Wide-angle X-ray diffraction indicated that intercalation of Jeffamine was successful. Thermogravimetry confirmed that nano-ZnO particle forced the expulsion of Jeffamine outside ZrP galleries. Scanning electron microscopy evidenced the Jeffamine intercalation and sample heterogeneity. Hydrogen molecular relaxation indicated the increase of molecular rigidity owing to the formation of ionic specie and the addition of nano-ZnO particles. It was postulated that a multifunctional and miscellaneous material constituted by as prepared ZrP, some delaminated ZrP platelets and nano-ZnO particles was achieved. The material has potential for usage as filler in polymeric composites.

Formation process of composite plasma electrolytic oxidation coating containing zirconium oxides on AM50 magnesium alloy

The formation processes of a composite ceramic coating on AM50 magnesium alloy prepared by plasma electrolytic oxidation （PEO） in a K 2 ZrF 6 electrolyte solution were studied by scanning electron microscope （SEM） and energy dispersive X-ray spectroscope （EDX）. Electrochemical impedance spectroscopy （EIS） tests were used to study the variation of the corrosion resistance of the coating during the PEO treatment. The results show that the coating formed on Mg alloy is mainly composed of MgO and MgF 2 when the applied voltage is lower than the sparking voltage, and zirconium oxides start to be deposited on Mg substrate after the potential exceeding the sparking voltage. The corrosion resistance of the coating increases with increasing the applied voltage.

Effect of zirconium addition on microstructure and mechanical properties of Mg_(97)Y_2Zn_1 alloy

The effects of zirconium addition on the microstructure and mechanical properties of Mg97Y2Zn1 alloy were investigated.The microstructure of as-cast Mg97Y2Zn1 alloy is refined by the addition of zirconium.During the extrusion,the initial nucleation sites of the alloy are mainly original grain boundaries and secondary phase.The addition of zirconium could stimulate the DRX process because more grain boundaries are formed,which increases the dynamic recrystallization rate.Both the strength and elongation of the alloy are increased by the addition of zirconium.

Deformation twinning and textural evolution of pure zirconium during rolling at low temperature

Industry pure zirconium sheets with a strong c-axis fiber texture were rolled to different strains at 77 K to investigate the twinning behavior and deformation mechanism. The microstructure and texture of the rolled specimens were characterized by scanning electron microscopy （SEM） together with electron backscatter diffraction （EBSD） techniques. The results show that the {1022} （1123） compression twinning mode is the dominant deformation twin at low strains loaded along the c-axis, and the {1012} （ 10]- 1 ） tensile twinning generates as the second twin in {1022} （ 1123 ） twins. The selection of twinning modes is governed by Schmid factor （SF） due to the calculating of SF and the EBSD simulating of twinning distribution. The evolution of texture during rolling affected by twins with increase of the strain was explained.

Experimental and Theoretical Study of Hydrogen Atom Abstraction from C2H6 and C4H10 by Zirconium Oxide Clusters Anions

The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules.

Hydrogenation of zirconium film by implantation of hydrogen ions

In order to understand the dnve-in target in a D-D type neutron generator,it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogenabsorbing metal film.The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions.Doses of 30 keV hydrogen ions ranging from 4.30×10^（17） to1.43×10^（18） ions cm^（-2） were loaded into the zirconium film through the ion beam implantation technique.Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy,atomic force microscopy and x-ray diffraction.Confirmation of the formation of 5 phase zirconium hydride in the implanted samples was first made by x-ray diffraction,and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.

Anodic dissolution behavior of zirconium in Bu_4~nNBr-containing isopropanol solution

Anodic dissolutionbehaviorof zirconium inBu^n 4NBr-contaningisopropanol solution was investigated using cyclic voltammetry, linear sweep voltammetry and chronoamperometry, complemented with a scanning electron microscope （SEM）.The voltammograms did not exhibit active dissolutionuntil the breakdown of passive layer induced by aggressive bromide anions.SEM images confirmed the existence of pits on zirconium surface.The depth and breadth of pits were intensified with increasing potential. The pitting potentialshifted negatively as either temperature orBu^n 4NBr concentration was increased, while it increased with increasing scan rate.The corrosion current density increased with increasing temperature. The apparent activation energyof anodic dissolutionofzirconiumwas 21.88kJ/mol. The chronoamperometry revealed that increasingBu^n 4NBrconcentration shortened the incubation time for passivity breakdown and accelerated the pit nucleation and growth. The experimental results were helpfulto obtain the optimum conditions for electrosynthesis of zirconium isopropoxide.

Microstructural evolution of zirconium alloy under dynamic compression at strain rate of 1000s^(-1)

Microstructural evolution of the zirconium alloy deformed at a strain rate of about 1000 s-1 was investigated. Four different strain levels of the zirconium alloy subjected to dynamic compression were designed by several-times impacting at almost the same strain rate. The results show that abundant low angle boundaries at different strain levels were observed in the deformed microstructures, and the quantity and density of low angle boundary increase dramatically with the strain increasing. Besides low angle boundaries and high angle boundaries observed in grain boundary maps, the twin boundaries including the tensile twins {10 2}, {11 1} and compressive twins {11 2} were distinguished at different strain levels, and most twin boundaries were indexed as {10 2} twins. With the stain increasing, the twin boundary density in the deformed microstructures increases indistinctively. Based on the characterization of the deformed microstructures at the different strain levels, the deformation and evolution processes of the zirconium alloy subjected to dynamic loading were proposed. Microhardness measurements show that the microhardness in the impacted specimens increases gradually with the strain increasing, which should be associated with the strain hardening caused by the tangled dislocation.

Effects of Ag-carrying Zirconium Phosphate on the Kinetics of Growth of the Roots of Culture Artemisia annua

在植物组织和细胞培养过程中 ,尤其是在生物反应器培养中的染菌问题 ,一直是制约植物细胞培养工业化的难题。通过比较各种防腐剂的抑菌效果 ,确定银型磷酸锆盐抗菌粉为青蒿根培养的最佳防腐剂。银型磷酸锆盐抗菌粉在浓度为 30mg/L时 ,既能降低培养液的染菌几率 ,又不明显抑制青蒿根的生长及青蒿素的生物合成。在添加 30mg/L抗菌粉的培养液中进行的青蒿根生长、pH值变化以及残糖、铵离子和硝酸根离子消耗的动力学研究表明 ,在 4 0d内青蒿根在培养液中生长良好 ,营养成分的消耗和对照呈相似的趋势。

Preparation of Silica Gels with High Adsorption Activity for Extraction of Zirconium

Silica gels with a high specific surface area and high adsorption activity ,which have high selectivity and high adsorption capacity for zirconium in acidic high level radioactive liquid waste (HLLW), have been prepared from water-glass and hydrochloric acid through adding surfactants. The surfactant modifies the surface of the primary sol particles, thus suppresses the growth of the primary particle,but accelerates their agglomeration. The action of the surfactant is similar to that of the organic structure-directing agent and makes the sol cluster cross-linkage ring-like network in short order. The specific surface area of the silica gel is 998 m 2/g; the static adsorption capacity and the adsorption distribution coefficient for zirconium in HLLW are 32.6 mg/g and 56.1 mL/g, respectively.

Surface finish effect on dry sliding wear behavior of thermally oxidized commercially pure zirconium

The effect of surface polishing on the wear behavior of thermally oxidized commercial pure zirconium (CP-Zr) under dry sliding conditions was investigated. Surface ground CP-Zr with a roughness of 0.21 μm (Ra) was thermally oxidized (TO) at 650 °C for 6 h. After TO, some samples were polished to smoothen the surface with a finish of 0.04 μm (Ra). The response of the polished and unpolished TO samples to dry sliding wear was investigated under unidirectional sliding conditions. The results show that surface polishing after TO affects the dry sliding wear behavior of TO CP-Zr in several aspects, including coefficient of friction, wear rate, crack formation and oxide layer breakdown. In particular, it is found that smoothening the TO surface favors the formation of semi-circular cracks in the wear track and accelerates oxide layer breakdown during dry sliding. A slightly rough TO surface helps to reduce the tendency of the oxide layer towards cracking and to increase the wear resistance at high contact loads. The mechanisms involved are discussed in terms of asperity contacts, crack formation, propagation and final fracture.