Ta2O5 Doping Research Articles

Ionizing Radiation Shielding Properties of Tantalum Pentoxide Doped High-Density Polyethylene Composites: A Theoretical Study

The rise in the utilization of radiation across various domains necessitates the advancement of next-generation radiation shielding materials that are devoid of lead. Due to their low weight and flexibility, polymer composites are considered as environmentally friendly alternative materials that can be used instead of toxic and high-weight lead for radiation shielding. From this point of view, the present study has focused on examining the radiation shielding performance of tantalum pentoxide doped high-density polyethylene (HDPE/Ta2O5) composites (including 5, 10, and 20 wt% Ta2O5) by using WinXCom software and MCNP6 simulation. The photon energies selected corresponded to the photons emitted from the Ba-133 (81 and 356 keV), Cs-137 (662 keV), and Co-60 (1173 and 1332 keV) radioactive sources that cover X-rays along with the low-and mid-energetic gamma-rays. The mass attenuation coefficient (/) of the composites has been calculated within the 81 keV-1332 keV photon range by utilizing WinXCom software and MCNP6 code. The other shielding parameters such as Half Value Layer (HVL), effective atomic number (Zeff), and effective electron density (Neff) have been determined. In the light of data, it has been revealed that gradual increase in Ta2O5 doping while improving the / coefficients, Zeff, and Neff parameters, decreasing the HVL length of HDPE considerably. Additionally, the parameters obtained by WinXCom and MCNP6 simulation are in good agreement. the. Ultimately, the best ionizing shielding performance among the composites has been determined for HDPE/20% Ta2O5 composite against 81 keV photons.

Ta2O5 doping effects on the property improvement of HfOx-based RRAMs using co-sputtering deposition method

Ta2O5 doping effects on the property improvement of HfOx-based RRAMs using co-sputtering deposition method

Cytocompatibility and osteogenic activity of Ta-Ti-O nanotubes anodically grown on Ti6Al4V alloy

Bioactive composition and bionic topography are highly desired in the surface design of biomedical implant materials. Herein, Ta-Ti-O nanotubes (NTs) were anodically grown on a tantalum (Ta) alloyed Ti6Al4V (Ta/TC4) surface. Ta/TC4 shows a scalelike surface and (α'+β) microstructure with a thickness of 11.7 μm, while Ta-Ti-O NTs exhibit a lamellar topography with ∼ 1.0 μm in length and 48.6 nm in diameter. Ta-Ti-O NTs group has the lowest water contact angle of ∼ 16.5° compared with TC4, Ta/TC4, and Ti-O NTs grown under the same electrochemical conditions. In vitro assays show that Ta-Ti-O NTs are non-cytotoxicity to MC3T3-E1 osteoblasts and slightly hamper cellular proliferation, but the adhesion and spreading abilities are significantly enhanced than others. The alkaline phosphatase (ALP), collagen type-1 (COL 1), and extracellular matrix (ECM) mineralization levels of osteoblasts on Ta-Ti-O NTs were also improved and further confirmed by osteogenesis-related gene expressions like ALP, COL 1, OPG, and TGF-β1. The superior osteogenic activities of Ta-Ti-O NTs can be mainly ascribed to the combined effect of Ta2O5 doping and the lamellar distribution of NTs. In summary, Ta-Ti-O NTs film with excellent cytocompatibility and osteogenic activities will find its clinical application in the future.

Enhancement of significant colour properties through Ta2O5 incorporation into ZnO–TeO2 binary glasses: An effective method for purposeful utilizations in industry and technology

The fact that multicomponent glass systems offer tuneable optical properties according to different additive rates increases their potential for use in daily industrial and optoelectronic applications that require high optical and colour performance. Therefore, it is vital to determine the optical and colour performances of glass systems in detail. The purpose of this research is to examine the monotonic effects of Ta2O5 on a set of glass samples and the resulting changes to colour concepts to better understand how to acquire these changes at their optimum level and make the most of the optimization possibilities available with Ta2O5. Accordingly, many optical properties such as Average Visible Transmittance (AVT), colour, Colour Render Index (CRI), Correlated Colour Temperature (CCT) that change with Ta2O5 doping ratio in binary Zinc-Tellurite oxide glasses-based systems are examined and their potential to be used for effective optoelectronic applications are presented. With the addition of Ta2O5 into (25ZnO·75TeO2)y(Ta2O5)x (x = 0–7 mol% and y = 100-x mol%) glassy system, all optical and colour properties were improved significantly. The Ta2O5 contribution increases the AVT and changes the colour coordinates of the glass system along the Planckian locus curve from the yellow region to the D65 colour coordinates. In addition, a comprehensive analysis of 15 coloured samples is provided, focusing on the cases in which Ta2O5 enhances the CRIext value. An enrichment was observed for TCS07 and TCS14, and a value of 100 was obtained specifically for TCS09 with a 3% Ta2O5 contribution. It can be concluded that the Ta2O5 is a promising multi-functional tool for colour enhancement of ZnO–TeO2 binary glasses making them more suitable for daily applications as well as applications in advanced technological purposes.

Comprehensive properties and thermal stability of Ta2O5-doped PIN-PHT ceramics

Herein, high-performance 0.11 Pb(In1/2Nb1/2)O3-0.89 Pb(Hf0.47Ti0.53)O3-0.8Ta2O5 (PIN-PHT-0.8Ta) ceramics are successfully synthesized. In addition, performance improvement is comprehensively analyzed from viewpoints of microstructure, phase structure and electrical properties. Experimental results reveal that the addition of Ta2O5 changes phase structure of PIN-PHT ceramics from ferroelectric tetragonal phase to rhombohedral phase. This leads to the appearance of morphotropic phase boundaries (MPBs). At the same time, the addition of Ta2O5 reduces grain size and enhances grain uniformity. Also, Ta2O5 doping improves internal and external contribution of piezoelectric response, which greatly improves dielectric, piezoelectric and ferroelectric properties of PIN-PHT. Key performance parameters include d33, kp, TC, εr and tanδ, which are found to be 630 pC/N, 0.73, 322.6 °C, 1917 and 1.55%, respectively. In particular, thermal stability of PIN-PHT-0.8Ta ceramics is found to be higher than PZT-based ceramics, as well as d33 value and performance retention rate of PIN-PHT-0.8Ta are found to be 560 pC/N and 89% at 300 °C, respectively, which are far superior to commercial PZT-5 and PZT-8 ceramics. These properties indicate potential of PIN-PHT-0.8Ta ceramics in high-temperature applications.

Effect of TiO2 and Ta2O5 co-doping on phase stability, fracture toughness, and sintering behavior of ZrO2 stabilized by 10mol%(Y0.4Gd0.3Yb0.3)2O3

The effect of TiO2 and Ta2O5 co-doping on the phase structure, fracture toughness, and sintering behavior of 10mol%(Y0.4Gd0.3Yb0.3)2O3-stabilized zirconia was investigated using X-ray diffraction, scanning electron microscopy, microindentation, and pressureless sintering. The results showed that 10mol%(Y0.4Gd0.3Yb0.3)2O3–ZrO2 had a single cubic phase structure, and an increase in the Ta2O5 (≥6 mol%) and TiO2 doping concentrations resulted in a simultaneous increase in the content and stability of the tetragonal phase. The fracture toughness of TiO2 and Ta2O5 co-doping 10mol%(Y0.4Gd0.3Yb0.3)2O3–ZrO2 decreased with an increase in the Ta2O5 content. On the other hand, the TiO2 content had no significant effect on the fracture toughness of 10mol%(Y0.4Gd0.3Yb0.3)2O3–ZrO2. The sintering resistance of the specimens increased with an increasing in the Ta2O5 content; however, an increase in the TiO2 content accelerated the densification of the specimens. When the Ta2O5 content was 10 mol% and the TiO2 content was in the range of 4–8 mol%, a single non-transformable tetragonal phase structure with fracture toughness similar to that of 6–8 wt% Y2O3 stabilized ZrO2 and excellent anti-sintering properties could be obtained. This structure can be explored as a thermal barrier coating material for high-temperature applications.

Role of zirconia phase transformation, interface processes, and Ta2O5 doping on the blistering phenomenon of molten glass in contact with zirconia-based refractories

Bubble formation and removal within the molten glass is an important issue in glass industry. Various sources of bubbles have been identified in glass manufacturing: decomposition of the glass components, air trapping, oxidation/reduction reactions, precipitation resulting from insufficient refining, etc. It has been demonstrated in a previous paper that the blistering phenomenon at the interface between a molten glass and a zirconia-based refractory can be ascribed to the oxygen semipermeability through the zirconia phase. The objective of this study is to clarify the role of temperature on the blistering process, and especially, below and above the phase transition temperature of zirconia (monoclinic/tetragonal transformation) and to evaluate the role of zirconia doping on the blistering level. The influence of the kinetics of the surface processes at the glass/refractory interface is emphasized. Quantitative measurement of the slight blistering ascribed to the so-called “redox shock” is also given.

Ta2O5 nanocrystals strengthened linear, nonlinear, and Faraday properties of heavy metal oxide diamagnetic material

AbstractIn this study, for the first time the diamagnetic 5d0 Ta5+ ions and Ta2O5 nanocrystals were utilized to enhance the thermal stability, optical linear and nonlinear, and Faraday rotation of diamagnetic glasses. Temperature‐dependent crystal morphology, phases, and structures of Ta2O5 were studied and 50 nm spherical δ‐Ta2O5 nanocrystal was obtained and shown decreased band gap of 3.68 eV. Transparent Ta2O5 nanocrystal doped diamagnetic glasses were obtained, and the embedded Ta2O5 nanocrystals have size ranging from 50 to 80 nm. EDX, XRD, FT‐IR, and Raman analysis indicated that Ta2O5 partially dissolved into glass as TaO6 octahedral units, while partially residual as undissolved Ta2O5 nanocrystals. Ta5+ ions strengthened the network connectivity of 1%–5% Ta2O5‐doped glasses, but Ta5+ acted as network modifier in 10% doped sample and changed the frame coordination units of glass. Therefore, 1% and 5% Ta2O5‐doped glasses showed high Tg and large thermal stability (107° and 120°). All Ta2O5‐doped glasses exhibited broad and intense optical emission at 420 nm, excellent nonlinear refractive index (5.22 × 10−14 cm2/W) and giant Verdet constant (56.19 rad/T·m) due to the increase in density, polarizability, and diamagnetic susceptibility by Ta2O5 doping.

Ta2O5-doped zinc-borate glasses: physical, structural, optical, thermal, and radiation shielding properties

In this study, examination of the physical, structural, optical and thermal properties of the glasses with the glass composition (100 − x)(0.6ZnO·0.4B2O3)·xTa2O5 (0, 1, 2, 3, 4 mol%) was aimed. Physical properties of the glasses synthesized with the classical melt-quenching method were calculated; density and molar volume values of the synthesized glasses based on the doping quantity were calculated. FTIR spectra were used in order to determine the structural properties in doped glasses. During the optical examinations of the synthesized glasses, direct and indirect optical band gap values were obtained with the help of Tauc plot method, and Urbach energies were calculated. Glass transition temperatures, melting temperatures, crystallization temperatures, and thermal stabilities were determined with DSC analysis. The main purpose of this study is to synthesize high-density glasses by adding higher-density Ta2O5 instead of relatively low-density chemicals (ZnO and B2O3) and to examine the radiation shielding properties of these glasses. Therefore, the effect of Ta2O5 doping on gamma and neutron radiation shielding properties was investigated using Geant 4 Monte Carlo toolkit. It was observed that Ta2O5 doping increased radiation shielding properties significantly. Especially, the increase in gamma radiation shielding properties was determined to be more compared to the increase in neutron radiation shielding properties.

Influence of Ta2O5 Doping on Electrical and Dielectric Properties of Nanocrystalline NiCuZn Spinel Ferrite

AbstractThe nanocrystalline Ni0.4Cu 0.3Zn0.3Fe2O4ferrite is prepared by sol–gel method by doping Ta2O5 (0 to 10 wt%). This paper presents effect of Ta2O5 doping on electrical and dielectric properties of nanocrystalline NiCuZn ferrite. The XRD patterns of the synthesized samples reveal single phase cubic structure and show the secondary phase of FeTaO4 with increasing Ta2O5 composition. From FESEM, agglomeration of spherical particles is observed. Direct current electrical resistivity is measured by two probe method. The investigated ferrite samples exhibits semiconducting nature property as resistivity decreased with the increase in temperature. The variation of dielectric constant and dielectric loss tangent for all samples are presented as a function of the frequency. The result also shows that as frequency is increased there is an increase in alternating current conductivity at room temperature.

Influence of Y2O3 and Ta2O5 Co-doping on Microstructure and Thermal Conductivity of Gd2Zr2O7 Ceramics

Rare earth zirconates (RE2Zr2O7) are considered as a class of potential high-temperature structural materials. In this paper, a series of Y2O3 and Ta2O5 co-doped Gd2Zr2O7 [(Gd1−xYx)2(Zr1−xTax)2O7+x, x = 0, 0.1, 0.2, 0.3, 0.4] ceramics were prepared by solid-state reaction sintering in order to clarify the influence of Y2O3 and Ta2O5 co-doped on microstructure, Young’s modulus and thermal conductivity. The results showed that Y2O3 and Ta2O5 co-doped Gd2Zr2O7 exhibited a single pyrochlore structure, and a small amount of Y3+ ions were doped into the Zr4+ ions lattice. The Young’s moduli of doped Gd2Zr2O7 ceramics slightly change with the increase in Y2O3 and Ta2O5 doping concentration. The minimum thermal conductivities of the specimens were obtained at 800 °C. The thermal conductivity of doped Gd2Zr2O7 with x = 0.3 is lower than that of others among the doped specimens, which is around 1.41 W m−1 K−1 at 800 °C. In addition, (Gd0.7Y0.3)2(Zr0.7Ta0.3)2O7.3 ceramic exhibits excellent phase stability from room temperature to 1550 °C.

Effects of Ta2O5 addition on relaxation behavior and electric properties of PMS–PNN–PZT ceramics

Pb(Mn1/3Sb2/3)0.01(Ni1/3Nb2/3)0.495(Zr0.3Ti0.7)0.495O3+x wt% Ta2O5 (PMS–PNN–PZT, x = 0, 0.2, 0.4, 0.6, 0.8) lead piezoelectric ceramics were prepared by a traditional two-step solid-state reaction method. The effect of Ta2O5 content on the phase structure, microstructure, electrical properties and dielectric relaxation of PMS–PNN–PZT ceramics was investigated. The XRD patterns show that all ceramics have pure perovskite structure. Ta2O5 doping can promote the grain growth and improve electrical properties. And the ceramics have high relaxation behavior. When x = 0.4, it exhibits optimum electrical performance: d33 = 805 pC/N, kp = 66%, er = 6838, tanδ = 1.4%, Tc = 118.5 °C, γ = 1.9618, Ec = 3.652 kV/cm, Pr = 21.91 µC/cm2. This indicates that Ta2O5 can be used as an effective dopant in PMS–PNN–PZT ceramics and the ceramics can be used as the main material for multilayer ceramic capacitors and electro-strictive actuators.

Dielectric properties and microstructures of Ta-doped BaTiO3–(Bi0.5Na0.5)TiO3 ceramics for X9R applications

Ta-doped 0.90BaTiO3–0.10(Bi0.5Na0.5)TiO3 ceramics were successfully prepared by conventional solid-state reaction method and studied to satisfy super-broad temperature stability. The effects of Ta2O5 doping on the dielectric properties and microstructures were thoroughly investigated. Ta plays an important role in the formation of core–shell structure because of chemical inhomogeneity, which gives rise to the weak temperature dependence of dielectric properties. The samples with the additon of 1.5 mol% Ta2O5 satisfy the X9R specification, exhibiting an optimum dielectric behavior of er ~ 2100, tanδ ~ 1.6% at room temperature, which is a promising candidate material for X9R MLCC applications.

Fabrication and testing of high performance acoustic emission sensor with Ta-Doped lead zirconate titanate

The piezoelectric and dielectric properties of ceramics containing Pb(Zr0.54Ti0.46) O3 + 0.2 wt.% Cr2O3 + x wt.% Ta2O5, where x = 0.0 to 5.0, were investigated for the development of a high performance acoustic emission (AE) sensor. The experimental results indicated that the specimen containing 2.0 wt.% Ta2O5 showed the superior piezoelectric and dielectric properties: electromechanical coupling factor = 68.5 %; piezoelectric constant = 467 × 10−12 m/V; mechanical quality factor = 84; and relative dielectric constant = 1731. Also, the AE sensor with the specimen containing 2.0 wt.% Ta2O5 showed the best sensor performance with the highest signal intensity of the tested AE sensors with 7.53 V, which was improved by 212 % in comparison to that of the AE sensor using the specimen without Ta2O5 doping. The improvement in performance of the AE sensor could allow for the reliable diagnosis in real-world applications for the protection of the system against thermal and mechanical disturbances.

Influence of Ta2O5 doping and microwave sintering on TiO2-based varistor properties

TiO2 based varistor materials with Ta2O5 dopants are prepared by microwave sintering (MS) and conventional sintering (CS). The sintering characteristics, sintered microstructures, varistor voltage (V1mA), nonlinear coefficient (α) and leak current (IL) are studied. The influences of the doping amount of Ta2O5 on the above properties are discussed. For similar sintered densities, the microwave sintering can decrease the sintering temperature by about 250°Cwhile improving the microstructure of the samples. Microwave sintering leads to better properties than conventional sintering. The samples have the best overall properties when the doping amount of Ta2O5 is in the range from 0.075mol% to 0.125mol%.

Thermoelectric Properties of Undoped and Doped (Ti0.75Sn0.25)O2

Thermoelectric properties of undoped and doped (Ti0.75Sn0.25)O2 were investigated for high‐temperature thermoelectric conversion application. Nano‐composites were formed by annealing above 1000°C. Outside the spinodal dome, ilmenite‐type SnTiO3 precipitated from the rutile structure. Thermoelectric properties were measured in the temperature range from room temperature to 1000°C. (Ti0.75Sn0.25)O2 was doped with both acceptor and donor dopants. Both undoped and doped (Ti0.75Sn0.25)O2 exhibit n‐type electrical behavior independent of the type of the dopant. The electrical conductivity was enhanced three orders of magnitude by donor doping with Nb2O5 or Ta2O5; achieving a maximum of 546 S/m at 850°C. The increase in electrical conductivity was accompanied by reduction of the absolute Seebeck coefficient. Seebeck coefficient reduction of −600 μV/K was observed between undoped and 4% Ta2O5 doped samples. The solid solution and doping reduced the thermal conductivity to <4 W/mK, far below the parent materials TiO2 and SnO2. Lattice thermal conductivity decreased with increasing temperature, achieving 1.9 W/mK at 900°C for 4% Ta2O5 doping. No further reduction in thermal conductivity was observed in annealed samples containing nano‐sized SnTiO3 precipitates. Dimensionless figure of merit (ZT) attained was <0.1.

Effect of Ta2O5 Doping on Electrical Characteristics of SrTiO3 Metal–Insulator–Metal Capacitors

The effect of Ta2O5 doping on electrical characteristics of SrTiO3 (STO) metal–insulator–metal (MIM) capacitors was studied for the first time. Using Ta2O5-doped STO dielectrics, an absolute quadratic voltage coefficient of capacitance (VCC-α) of 510 ppm/V2 and a high capacitance density of ∼20 fF/µm2 are achieved. These are approximately one order of magnitude lower than those of the MIM capacitor fabricated using a pure STO. In addition, the degradation of electrical properties (capacitance variation versus voltage, VCC-α, and long-term reliability) after electrical stressing is reduced, compared with that of an MIM capacitor fabricated using a pure STO.

Granular L10 FePt–X (X=C, TiO2, Ta2O5) (001) nanocomposite films with small grain size for high density magnetic recording

Fe Pt – X (X=C, TiO2, Ta2O5) nanocomposite films were deposited on MgO∕CrRu∕glass substrates at 350°C by magnetron cosputtering. The comparison investigations on the magnetic properties and microstructure of FePt–X films with various dopants were conducted. All FePt–X films showed (001) preferred orientation and oxide dopants promoted the formation of magnetically soft fcc FePt phase. With 15vol% C doping, FePt–C film with columnar grains of 7.5nm was obtained and the out-of-plane coercivity measured at room temperature was as high as 14.4kOe. The increase in carbon volume fraction to 20% caused the formation of two-layer structure, whereas for the 20vol% TiO2 and Ta2O5 doping, the columnar structure of the FePt films remained and the corresponding grain sizes were 5 and 10nm, respectively. Ta2O5 doping showed better grain isolation than the others. The out-of-plane coercivities of FePt–TiO2 and FePt–Ta2O5 films were 7.5 and 8.8kOe, respectively.

Doping Effects of Ta on Conductivity and Microwave Dielectric Loss of MgTiO3 Ceramics

Two kinds of solid solution systems of Ta‐doped MgTiO3 were identified by X‐ray diffraction, which can be represented by the formulae MgTi1−x(Mg1/3Ta2/3)xO3 (0≤x<0.5) and MgTi1−xTaxO3 (0≤x<0.05). The conductivity and microwave dielectric loss for the two solid solution systems were examined by AC impedance and microwave resonator measurements, respectively. In the system MgTi1−x(Mg1/3Ta2/3)xO3, the mechanism for the solid solution formation is the isovalent substitution of for Ti4+. In the system MgTi1−xTaxO3, the doping mechanism is the aliovalent substitution of Ta5+ for Ti4+, where for a small amount Ta doping, the oxygen vacancies formed during the high‐temperature preparation are filled by an extra oxygen introduced from Ta2O5 and further Ta doping leads to an increase in the contents of and electrons, which was consistent with conductivity measurements. In both systems, the Q×f values improved, e.g., ∼17% for the isovalent substitution at x=0.08 and ∼10% for the aliovalent substitution at x=0.02. The filling oxygen vacancy and the substitution of Ta/Mg for Ti may contribute to the improvement of Q×f values for both systems.

Electrical properties of Li2O-La2O3-SiO2 electrode glasses after Ta2O5 doping and Ta implantation

Electrical conductivities, σ, of the Li2O-La2O3-SiO2 glasses were investigated as functions of Ta2O5 doping and Ta ion-implantation. A linear relationship between logarithm σ and the inverse of the sample temperature, T, was found in 2 to 4 mol% Ta2O5 doped Li2O-La2O3-SiO2 glasses. The conductivity increases as Ta2O5 content increases at sample temperatures above 100°C. Fluences of 50 keV Ta ions per cm2 from 5 × 1016 to 2 × 1017 were implanted into 0% and 2% Ta2O5 containing Li2O-La2O3-SiO2 glass samples. The activation energy of the conductivity was deduced from the relation between log σ and 1/T. It was found in implanted samples that the conductivity increased, but the activation energy and Tk−100 decreased, where Tk−100 is the sample temperature when the conductivity reaches 100 × 10−1 S/cm. However, the Ta2O5 containing implanted samples show higher conductivities, lower activation energies and lower Tk−100. X-ray photoelectron spectroscopy (XPS) was used to study the structural modification introduced by implantation. Bridging oxygen (BO) and non-bridging oxygen (NBO), were observed in all samples. The changes in relative concentrations of BO and NBO before and after implantation clearly indicate the structure modification which results in the increase of the conductivity. It was clearly demonstrated in this study that both doping Ta2O5 and implanting Ta ions enhance the conductivity of Li2O-La2O3-SiO2 electrode glasses.