Amount Of Zr Research Articles

Effect of trace Ni addition on microstructure, mechanical and corrosion properties of the extruded Mg–Gd–Y–Zr–Ni alloys for dissoluble fracturing tools

Magnesium alloys, a novel functional material for the fabrication of fracturing tools, are being paid more and more attentions recently due to their relatively high mechanical properties and fast dissolubility ability after fracturing. In this study, the novel extruded Mg–10Gd–3Y–0.3Zr–xNi alloys will be reported and their microstructure, mechanical and corrosion behaviors will be also studied. The results show that Ni contents influence phase precipitation behaviors. With adding 0.2 wt% Ni, a large amount of Zr 7 Ni 10 phases will be precipitated insides α-Mg matrix, directly leading to degradation of strength and large corrosion rate. With further increasing Ni contents, the precipitation phases can be changed from Mg 5 RE to 18R-LPSO structure, resulting in higher mechanical properties and faster corrosion rate. Moreover, adding Ni element also change the texture orientation by influencing the precipitation behavior of the alloys. The alloys invented in this paper have attained the highest compressive and tensile properties among all the reported dissoluble magnesium alloys. This work is beneficial in understanding the role of Ni in the magnesium alloys and provides more materials alternatives for the fabrication of dissoluble fracturing tools.

Thermal, mechanical and morphological properties of polyurethane–zirconia loading

Abstract The polyurethane (PU) has been showing a dramatic increase in applications related to material science and technology. However, the mechanical, physical and thermal properties could be further improved by loading PU with zirconia (Zr) to create renewable materials known as polyurethane–zirconia (PUZ) composites. In this study, PU matrix was treated with wt.% Zr at 0.5, 1.0, 1.5 and 2.0. In this study, the thermo-mechanical properties and the morphology were investigated of PU and PUZ nano-samples. The images of the scanning electron microscope (SEM) were the prime tool in investigating PU and PUZ surfaces and fractured surfaces showing vanishing the cracks and formation of agglomeration on the sample PUZ-1.5%. In addition, the tensile strength, Young’s modulus and maximum loading were improved by 36.7, 31.8 and 39.1%, respectively, at Zr loading of 1.5 wt.%. The flexural stress and the load were improved by 94.3% and 93.6%, respectively, when Zr loading was 1.5 wt.%. The impact without and with a notch was improved by 110.7% and 62.6%, respectively, at Zr loading of 1.5 wt.%. The the morphologies of the PU surface and Zr surface supported by SEM images. Regarding the storage modulus ability of PU and PUZ composites, Zr loading has negatively influenced E. The E functioning temperature was observed to move from 142 to 183°C. Another effect was determined by adding a small amount of Zr. This small amount was enough to shift the crystallization temperature (${T}_c$) and the melting temperature (${T}_m$) of PU from 125 to 129°C and from 150 to 144°C, respectively.

Lattice Stability and Elastic Properties of Zr-Ti-X Alloys (X = Al, V) by the First Principles Study

Based on a certain ratio of Zr and Ti atomic fractions according to Zr47Ti45Al5V3 (wt.%), the lattice constants, lattice stability, and elastic properties of Zr-Ti-X alloys (X = Al, V) in body-centered cubic (BCC) (β phase) and hexagonal close-packed (HCP) (α phase) crystal structures were studied using first-principles calculations. It is shown that Al acts as an α stabilizer for Zr-Ti-Al alloys and V can stabilize the β phase for Zr-Ti-V alloys. As the mass fraction of Al increases from 4 wt.% (Zr55Ti41Al4) to 6.8 wt.% (Zr53.2Ti40Al6.8), these alloys all have relatively good strength, hardness, and rigidity, however, their ductility deteriorated with the increasing of Al mass fraction. When the mass fraction of V in Zr-Ti-V alloys is 2.4 wt.%, Zr55.6Ti42V2.4 (wt.%) achieved the best strength, hardness, and rigidity, when the mass fraction of V increases from 0 (Zr57Ti43) to 12 wt.% (Zr50.2Ti37.8V12), their ductility improved. The changes of phase compositions and structure with Al content or V content distinctly affect mechanical properties of ternary Zr-Ti-X alloys (X = Al, V), the amount of Zr and Ti could be factors that impact the mechanical properties of the multiphase Zr47Ti45Al5V3 from the point of view of ternary Zr-Ti-Al and Zr-Ti-V compositions.

Ultrasound assisted casting method for fabricating B4Cp/Al composites with the addition of K2ZrF6

In this research ultrasound assisted casting method was applied to fabricate 10 wt.%B4Cp/Al composites with the addition of K2ZrF6. The effects of Zr content on the microstructure, including the distribution and the interface of B4C particles, as well as the mechanical properties of composites were investigated. Experimental results showed that an interfacial layer which was composed by nano-sized ZrB2 particles could be formed on B4C surface, which was beneficial for improving the dispersity and hindering the decomposition of B4C particles in the Al melt. As the addition amount of Zr satisfied the ratio of (wt.%Zr)/(wt.%B4C) = 0.2, the B4Cp/Al composites with a homogeneous microstructure had the best comprehensive and most stable mechanical properties.

Effect of Zr on catalytic performance of unsupported Ni(Zr)Mo and Ni(Zr)W sulfide catalysts for quinoline hydrodenitrogenation

To increase the dispersion of active species and full utilization of active metals are of great importance for hydrodenitrogenation (HDN) performance of unsupported hydrotreating catalysts. Herein, a series of unsupported Ni(Zr)MoS and Ni(Zr)WS catalysts were prepared from Ni(Zr) layered double hydroxide (LDH) precursors. The Zr species remarkably promote the dispersion and reducibility of NiMo and NiW composite species. Also, the total HDN rate constants are increased from 2.42 h−1 to 9.18 h−1 for Ni(Zr)MoS and from 5.68 h−1 to 23.0 h−1 for Ni(Zr)WS, and exhibit a maximum at a Zr/Ni atomic ratio of about 0.04. The HDN selectivities indicate that the Zr species increase the number of superficial active sites without affecting their structure. The present work shows that the crystallinity of LDH precursors is crucial to the structure of unsupported sulfide catalysts, and a suitable amount of Zr could be a dispersive promoter to increase the HDN activity.

Microstructure and properties of Nb-Mo-Zr based refractory alloys

Microstructure and mechanical properties of five Nb alloys containing 8 to 17 at.% Mo, 8 or 35 at.% Zr, up to 7 at.% Ti, up to 2 at.% Al and up to 2 at.% Cr are reported. These alloys have been developed to replace heavy, expensive and difficult to process commercial Nb alloys, such as C-3009, for use at temperatures up to 1600 °C. The density of the alloys is in the range from 7.6 to 8.6 g/cm3. The alloys have a BCC matrix phase, and they also contain small amounts of secondary phases, which are rich in Zr and have BCC, FCC, hexagonal or monoclinic crystal structures depending on the concentration of other alloying elements, including oxygen and nitrogen. In the temperature range from 25 °C to 1600 °C, the alloys with a smaller amount of Zr are ductile and have higher specific strength than C-3009. The alloy containing 35 at.% Zr is stronger, but less ductile, than other alloys at temperatures up to 600 °C; however, it loses the strength rapidly at higher temperatures and becomes softer than other alloys at T > 1000 °C. The possible strengthening mechanisms responsible for the observed temperature dependence of the yield stress of the alloys are also discussed.

(Sm,Zr)Fe12−xMx(M=Zr,Ti,Co)for Permanent-Magnet Applications:Ab InitioMaterial Design Integrated with Experimental Characterization

In rare-earth permanent magnets (REPM's), trade-off's between intrinsic magnetic properties are often encountered. A recent example is SmFe$_{12}$ where excellent magnetic properties can be achieved at the sacrifice of bulk structure stability. Bulk structure stability is sustained by the presence of the third substitute element as is the case with SmFe$_{11}$Ti, where Ti degrades magnetic properties. It is now in high demand to find out with which chemical composition a good compromise in the trade-off between structure stability and strong ferromagnetism is reached. We inspect the effects of representative substitute elements, Zr, Ti, and Co in SmFe$_{12}$ by combining ab initio data with experimental data from neutron diffraction. The trend in the intrinsic properties with respect to the concentration of substitute elements are monitored and a systematic way to search the best compromise is constructed. A certain minimum amount of Ti is identified with respect to the added amount of Co and Zr. It is found that Zr brings about a positive effect on magnetization, in line with recent experimental developments, and we argue that this can be understood as an effective doping of extra electrons.

Temperature dependence on ferroelectric properties and strain performance of PLZT ceramics containing 9 mol% La

ABSTRACT PLZT ceramics containing 9 mol% La and 50–70 mol% Zr were prepared by two-stage sintering to enhance the densification and the microstructure. Dielectric properties were investigated and the phase transition from relaxor to normal ferroelectric as an increasing amount of Zr could be observed. Induced strain (butterfly loop) and polarization (hysteresis loop) were measured at the maximum electric field of 12.5 kV/cm and the temperature range of 25–140°C. It was found that temperature dependence played an important role to phase transition from ferroelectric to paraelectric, which governed polarization and strain of PLZT ceramics. Zr/Ti ratios could also determine ferroelectric and induced strain properties where morphotropic phase boundary (MPB) would maximize polarization and strain in terms of piezoelectric coefficient.

The Effects of Cr and Zr Additives on the Microstructure and Mechanical Properties of A356 Alloy

This study has investigated the effect of different amounts of Cr and Zr additions on the microstructure and mechanical properties of A356 alloy modified with strontium. The microstructure and phase examination were performed using an optical microscope, scanning electron microscope and XRD analysis, whereas mechanical properties were investigated via tensile testing and hardness measurements. Two-dimensional Weibull distribution was used to determine the effect of Cr and Zr additions on mechanical properties of A356 alloy. It was found that the most significant effect of Cr and Zr added was over the morphology of Al–Si–Fe intermetallics. The addition of Cr and Zr led to the formation of Cr/Zr-based intermetallics in precipitates and fish-bone-like morphologies. It was observed that increasing the amount of Cr and Zr had resulted in an increase in ductility of A356.

Mechanical Behavior and Microstructure of Hot Deformation of with Er 7N01 Aluminum Alloy

In this paper, an Al-Zn-Mg-Cu alloy with a small amount of Er and Zr added was used as the research object. The homogenization annealing was carried out, and the 7N01 aluminum alloy was used at 300 °C, 350 °C, 400 °C, 450 °C and 0.1 s-1, 1 s-1, 10 s-1 deformation conditions by Gleeble-3500 thermal simulator. Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM) were used for microstructure analysis. The results show that the stress-strain curve of with Er 7N01 aluminum alloy can be divided into micro-strain stage, uniform deformation stage and steady-state flow stage during the thermal compression process. The flow stress of 7N01 aluminum alloy achieved peaks at the initial stage of strain, and then increased with the increase of strain rate and the decrease of deformation temperature. With the increase of deformation temperature and the decrease of deformation rate, the recrystallization process was significantly increased.

Understanding the role of Al/Zr ratio in Zr-Al-Beta zeolite: Towards the one-pot production of GVL from glucose

The direct one-pot transformation of glucose into γ-valerolactone (GVL) can be accomplished by means of a cascade of reactions in which Brønsted acid-catalyzed transformations are combined with catalytic transfer hydrogenation (CTH) by using 2-propanol as sacrificial alcohol, avoiding the use of high-pressure hydrogen. Catalysts containing Zr Lewis acid sites have been successfully applied in CTH reactions while the acid-driven transformations can be preferentially promoted by Brønsted Al-related acidity. Here, we present the combination of Zr and Al as active sites within a BEA zeolite structure as catalyst, with the possibility of adjusting the Al/Zr ratio from ∞ (commercial H-Beta) to 0 (aluminium-free Zr-Beta), which show a scale of Brønsted/Lewis acid sites ratios. The Al/Zr ratio has a strong impact on the products distribution. As the Zr content increases, higher amount of GVL is obtained, leading to a maximum over the catalyst with high amount of Zr and low content of Al acid sites (Al/Zr = 0.2). An increase of reaction temperature, as well as reaction time, allows an enhancement of yields towards the desired products, leading to a maximum yield towards GVL of 24 mol% over Zr-Al-Beta (2.0), and a maximum yield towards isopropyl lactate of 26 mol% over Zr-Beta at 190 °C.

Dense ZrB<sub>2</sub>-MoSi<sub>2</sub> Composite Coating Fabricated by a New Multi-Chamber Detonation Accelerator on Carbon/Carbon Composites

A new multi-chamber detonation accelerator (MCDS) was applied to fabricate ZrB2–MoSi2 composite coating containing 20 mol.% of MoSi2 on carbon/carbon composites. Phase composition and microstructure of the coating were characterized by X-ray diffraction and scanning electron microscopy. The ZrB2–20MoSi2 coating displayed compact and lamellar microstructure with porosity lower than 1%, where SiO2 phase was uniformly distributed in the ZrO2 matrix. The coating was well-adhered with carbon/carbon composites. Silica, m-ZrO2, and small amount of Zr(MoO4)2 were formed.

The Effects of Zr Addition on the Microstructure and Mechanical Properties of A356–SiC Composites

The influences of Zr on the microstructure of A356–15 vol% SiC composites, such as the distribution of SiC particles in the matrix, the grain size and the hardness and impression creep between 225 and 275 °C, were examined. These composites were prepared using the stir casting technique. The addition of Zr forms Al3Zr phases, which can act as heterogeneous nucleation sites, thus resulting in grain refinement. Furthermore, Zr leads to a more uniform distribution and an increased area fraction of SiC particles. Moreover, the addition of only 0.1 wt% Zr significantly increased the Brinell hardness by approximately 18% when compared to the composite without added Zr. The addition of a small amount of Zr (0.1 wt%) is sufficient to increase the Vickers microhardness by approximately 34% when compared to the composite without added Zr, indicating the effect of solid solution strengthening on the composite matrix. The high-temperature stability test using the impression creep technique demonstrated that the A356–15 vol% SiC composite with 0.1 wt% added Zr shows improved creep resistance. However, the creep resistance of composite samples with higher than 0.1 wt% added Zr decreases due to grain boundary sliding occurring in the A356–15vol% SiC composites with too much added Zr.

Study on the controlled synthesis of Zr/TiO2/SBA-15 nanophotocatalyst and its photocatalytic performance for industrial dye reactive red X–3B

Nanophotocatalytic technology is one of the most promising technologies to treat industrial dyes in waste water. Nanosized TiO2 was loaded on mesoporous SBA-15 molecular sieve by chemical method to prepare TiO2/SBA-15 (TS1) in this work. Then, the transition metal element Zr was further deposited on the surface of TS1 to obtain Zr/TiO2/SBA-15 (ZTS) nanophotocatalysts. The crystal structure, morphology, element distribution and pore size distribution of several samples were studied using small-angle x-ray scattering, X-ray diffraction, Transmission electron microscope, Scanning electron microscope, X-ray photoelectron spectroscopy, N2 adsorption-desorption, UV–Vis diffuse reflectance spectroscopy. The photocatalytic performance of the nanophotocatalyst was evaluated by photocatalyzing reactive red X–3B. The results show that the ZTS nanophotocatalyst has a good mesoporous structure, wherein, the TiO2 is an anatase phase. The specific surface of ZTS reaches 538.24 m2/g and its spectral absorption threshold reaches 425 nm. When the deposition amount of Zr is moderate the ZTS nanophotocatalyst shows quite high photocatalytic activity. In pH 2–10, the photocatalytic activity of ZTS exhibits change with variation of pH value. Under proper conditions, the degradation rate of reactive red X–3B reaches about 96% in ZTS photocatalytic system. Therefore, ZTS nanophotocatalyst has great potential in the treatment of dye wastewater.

The structural evolution and multiferroic properties of nonstoichiometric BiFe1−4x/3ZrxO3 ceramics with Fe vacancies

Nonstoichiometric BiFe1−4x/3ZrxO3 (0 ≤ x ≤ 15%) multiferroic ceramics with Fe vacancies were synthesized by using rapid liquid phase sintering process. It was found that nonstoichiometric Zr substitution induced structure distortion, and an appropriate amount of Zr could remove impurity phases. XPS and PAS studies indicated that there was no obvious change in Bi vacancies concentration, but the Fe vacancies concentration increased with increasing substitution amount of Zr. The Fe2+ concentration first decreased and then increased with the increase in substitution amount of Zr, while the oxygen vacancies concentration decreased with increasing substitution amount of Zr. Nonstoichiometric Zr substitution could effectively enhance the multiferroic behaviors of BiFeO3. The evolution of structure and properties induced by nonstoichiometric Zr substitution indicated that Fe2+ concentration was the main source of the leakage current, while Fe vacancies concentration was a key factor that modulated the magnetic performances of BiFeO3. Furthermore, the applied magnetic field dependence of dielectric constant suggested that the magnetodielectric effect increased with increasing Zr substitution amount. The results above imply that nonstoichiometric BiFeO3 composition with Fe vacancies has great potential for exploiting high quality BiFeO3-based ceramics.

Effects of Ti and Zr elements addition on the microstructure and corrosion resistance of Zn-2.5Al-2Mg alloy

In this article, the effects of Ti and Zr elements addition on the microstructure and corrosion resistance of Zn-2.5Al-2Mg alloy were studied. The microstructure, micro hardness, corrosion resistance of Zn-2.5Al-2Mg alloy were investigated by x-ray diffraction (XRD), Scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), Rockwell hardness tester and Electrochemical workstation, respectively. The result shows that the solidified structure of Zn-2.5Al-2Mg alloys was refined by Al3Ti, Al3Zr and Al3(Ti, Zr) which act as a heterogeneous nucleation site. Moreover, the Rockwell hardness of Zn-2.5Al-2Mg alloys with the addition of Zr was significantly increased. The hardness of this alloy with the same amount of Zr and Ti addition is lower than that of the alloy with Zr addition alone, but obviously higher than that of the alloy with Ti alone. The corrosion resistance of the Zn-2.5Al-2Mg alloys with the same amount of Zr and Ti addition was improved significantly.

Effect of tiny amount of impurity and convective transport on dendrite growth kinetics

Using the developed sharp-interface model of solidification we quantitatively estimate influence of tiny amount of impurity and forced convection on kinetics of dendritic growth. As tested systems, we choose Ni and Ni–Zr dendrites which are growing into a stagnant undercooled melt, the melt with incoming forced flow and with/without impurity (that is small amount of Zr diluted in a pure Ni). The model predictions and comparisons allow us to quantitatively estimate predominant influence of impurity (chemical segregation), thermal influence (due to temperature inhomogeneity) and hydrodynamic effects (due to investigated laminar and forced melt flow) on the dendrite growth kinetics.

Release of ZrO2 nanoparticles from ZrO2/Polymer nanocomposite in wastewater treatment processes

The widespread use of nano-enabled water treatment composites (NWTCs) can result in the release of nanoparticles (NPs) into environmental waters. Studying the release of NPs from NWTCs is of great significance for evaluating the material stability, and environment and biological safety. This work evaluated the amount and species of Zr released from a NWTC, a ZrO2/polymer composite (HZO@D201), during the treatment of electroplating wastewater. About 5 g of the HZO@D201 particles, consisting of porous spheres (0.8 mm in diameter) loaded with ZrO2 NPs, were packed into a glass column (130 mm in length and 20 mm in diameter) and treated with wastewater at a flow rate of 25 mL/hr. The release of Zr occurred mainly in the initial stages of water treatment, decreased with the increase of treatment volume, and approached an equilibrium value of approximately 3.79 μg/L at the treatment volume of about 800 bed volumes. The total amount of Zr released in the effluent was in the range of 2.62–140 μg/L, which was mainly present in the form of ZrO2 NPs. The amounts of Zr released under acidic and alkaline conditions were markedly higher than that under neutral conditions, while the presence of humic acid significantly inhibited the release of Zr. Our study implied that the NWTCs could be a source of engineered NPs in environmental waters, and should be considered in evaluating the safety of ZrO2/polymer composites in water treatment.

Effect of Zr Target Current on the Mechanical and Tribological Performance of MoS2–Zr Composite Lubricating Coatings

To improve the tribological properties of pure MoS2 coating, the MoS2–Zr composite lubricating coatings were prepared on the WC/TiC/Co carbide surface utilizing radio frequency magnetron sputtering method combining with multiple arc ion plating technology. The effects of different Zr target currents on the surface morphologies, roughness, Zr content, adhesive force, thickness, microhardness and tribological behaviors of the composite coatings were systematically investigated. Results showed that the properties of MoS2 coating can be remarkably enhanced through co-deposition of a certain amount of Zr. As the Zr target current increased, the Zr content, surface roughness, thickness, and micro-hardness gradually increased, while the adhesive force of coatings increased first and then decreased. The friction behaviors and wear modes of the composite coatings both varied obviously with the increase of Zr current. The mechanism was mainly attributed to the different components and mechanical properties of the coatings caused by various Zr current.

A Chemometric Study of the Adsorption of Zr(IV) Ions from Aqueous Solutions onto TBP-Surface-Modified Magnetic Fe3O4 Nanoparticles as a New Adsorbent

Chemometric experimental design methods were used to optimize the adsorption of Zr(IV) ions from an aqueous solution. Tributyl phosphate functionalized magnetic nanoparticles (TBPFMNPs) were used as a novel adsorbent for the adsorption of Zr(IV) ions. The effect exerted on the adsorption process by the adsorbent amount (mg), TBP/MNP ratio (w/w, %), and concentration of Zr(IV) in aqueous solutions (mg/L) was studied. Two-level factorial design was used, with the other parameters kept constant in the batch experiments. The initial Zr concentration was varied from 3.5 to 70 ppm with 9 mg of the adsorbent. The maximum uptake, 93%, was reached at the initial zirconium concentration of 35 ppm. The maximum distribution coefficient under these conditions reached 15140 mL/g.