Addition Of Ta2O5 Research Articles

Non-isothermal crystallization kinetics for CaO–SrO–B2O3–Al2O3–Bi2O3–SiO2 glass system with Ta2O5 addition

The effect of Ta2O5 at the rates of 1, 2, 3 and 4 % mol on the CaO–SrO–B2O3–Al2O3–Bi2O3–SiO2 glass system was examined by the melt-quenching at 1400 °C. Non-isothermal crystallization kinetics of the compounds were calculated using Differential Scanning Calorimetry (DSC). The kinetics study revealed activation energy values of 109.4 kJ/mol for the T1 composition, 302.14 kJ/mol for the T2 composition, 471.5 kJ/mol for the T3 composition, and 344.7 kJ/mol for the T4 composition, as determined by applying the Kissinger method. According to the average of Avrami parameters, two-dimensional crystal growth was observed in T1 glass and surface crystallization was observed in all other glass. The glass forming ability (GFA) of the glasses was investigated with the values obtained as a result of HSM analysis. In the XRD analysis performed after heat treatment at 850 °C, crystal phase development was observed in the glasses. As a result of the crystallization process, it was observed that wollastonite, strontium aluminum silicate, strontium aluminum oxide and bismuth oxide phases were formed in T1, T2 and T3 glasses.

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.

Effect of Ta2O5 addition on the structure, crystallization mechanism, and properties of CaO–B2O3–SiO2 glasses for LTCC applications

CaO–B2O3–SiO2–Ta2O5 (CBST) glass-ceramics, with different Ta2O5 content, (up to 6 mol%), have been prepared by using glass melt quenching followed by heat treatment between 800 and 880 °C. The Fourier Transform Infrared (FTIR) results showed that the stronger the attraction of Ta5+ to the oxygens in the BO33− and SiO32− structures, the more easily the B–O and Si–O bonds will be destroyed. The underlying reason is most probably the high field strength of Ta5+, which results in a weakening of the vibration intensities of the [BO3] and [SiO4] units. Moreover, the Differential Scanning Calorimetry (DSC) results showed that the softening point (Tg), crystallization starting temperature (Tc1), and exothermic crystallization peak temperature (Tp1), of the CaSiO3 phase, shifted to higher values with the addition of Ta2O5. Also, the crystallization activation energy (Ea) and the glass stability factor (ΔT) of the CaSiO3 phase increased, which indicated that the CaSiO3 phase of the glass became inhibited by the addition of Ta2O5. It was, thus, obvious that there was a need of glass characterization. The results of the crystallization kinetics showed that the critical cooling rate decreased with the addition of Ta2O5, which indicated that the viscosity of the system had increased. The CBST glass-ceramics, containing 1 mol% Ta2O5, that were sintered at 875 °C for 15 min showed excellent dielectric properties: εr = 6.22 and tanδ = 1.19 × 10−3 (1 MHz). To sum up, CaO–B2O3–SiO2–Ta2O5 glass-ceramics are potential low temperature co-fired ceramic substrate materials.

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 [SiO2]/[Li2O] on the microstructure and properties of lithium disilicate glass-ceramics containing lithium tantalate as a secondary phase

Our previous work proposed a phase reaction equation for the current lithium disilicate (LD) glass-ceramic system containing lithium tantalate (LT) as a secondary phase: 2(Li2SiO3) + Ta2O5 → Li2Si2O5 + 2(LiTaO3). The present study had a goal of finding support for the proposed equation by examining the effect of the ratio of [SiO2] to [Li2O] on the phase assemblage and microstructure of this system. The study also examined the microstructural effects on several properties of this system. A 15-sample data set was created by designing three microstructures for each of the five compositions. It was found that the LT/LD ratio from X-ray diffraction peak counts, as well as from Rietveld refinement, increased in the material as [SiO2]/[Li2O] decreased, supporting the proposed reaction equation. As [SiO2]/[Li2O] decreased, bulk density and CTE increased, while L* (lightness vs darkness) and Knoop hardness values decreased. The microstructure had little effect on radiopacity, but the addition of extra Ta2O5 into the composition lead to increased radiopacity values.

Low power loss manganese ferrites with the addition of Ta2O5 for MHz applications

Dramatic increase of power loss in the MHz frequency range is the bottleneck problem for MnZn ferrites to be applied in high-frequency power electronic devices. In this work, manganese ferrites with low power loss in the frequency range of 1–3 MHz have been developed by the addition of Ta2O5. The manganese ferrite with 300 ppm Ta2O5 exhibits excellent Pcv performance. Pcv at 25 °C is as low as 41, 94 and 164 kW/m3 under measurement conditions of 1 MHz/50 mT, 2 MHz/50 mT and 3 MHz/30 mT, respectively. Excellent temperature stability of power loss in the temperature range of 25–140 °C is also achieved in this sample. Power loss was divided to three parts of hysteresis loss, eddy current loss and residual loss. Ta2O5 segregates at grain boundaries and reduces all three parts of loss. The mechanism of Ta2O5 influence on each part of loss has been clarified.

Low Power Loss Manganese Ferrites with the Addition of Ta2o5 for Mhz Applications

Low Power Loss Manganese Ferrites with the Addition of Ta2o5 for Mhz Applications

Ta2O5-doped TiO2 nanotubes on Ti6Al4V alloy with improved cytocompatibility to endothelial cells

Microscopic topography and chemical composition of implant surface play critical roles in cellular response. In this work, Ta2O5-doped TiO2 nanotubes (Ta2O5/TiO2 NTs) were prepared on Ti6Al4V (TC4) to improve its cytocompatibility to endothelial cells. Firstly, a Ta diffusion layer on TC4 (Ta/TC4) was designed by plasma surface Ta-alloying. Then, a Ta2O5/TiO2 NTs film was grown on Ta/TC4 by anodization. The surface morphology, phase composition, and microstructure of the obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Ta incorporation leads to the lamellar microstructure (α'+β) of Ta/TC4 and the lamellar distribution of Ta2O5/TiO2 NTs. In vitro assays demonstrate that the synergistic effect of Ta2O5 addition and biomimetic nanostructure is responsible for the enhanced proliferation, adhesion, cytoskeletal assembly, and spreading of endothelial cells on Ta2O5/TiO2 NTs. The excellent cytocompatibility of Ta2O5/TiO2 NTs highlights its potential in biomedical applications.

Influence of Ta2O5 Addition on Thermophysical Performance of Sm2Ce2O7

Influence of Ta2O5 Addition on Thermophysical Performance of Sm2Ce2O7

The Effect of Ta<sub>2</sub>O<sub>5</sub> on the Densification Behaviour and Mechanical Properties of Zirconia-Toughened Alumina (ZTA) Composites Prepared by Two-Stage Sintering

By 2050, 130 million people are estimated to suffer from osteoarthritis worldwide which would require patients to undergo total hip replacement procedure which have a lifespan of 20 years and failure rates of ~1%. In this research, Zirconia Toughened Alumina (ZTA) which is the main biomaterial used for total hip arthroplasty were doped with varying vol % of Tantalum Oxide (Ta2O5) from 0 to 0.4 vol % were produced through conventional two-stage sintering with first stage sintering temperature, ranging between 1400°C and 1550°C, heated at 20°C/min, followed by second stage sintering temperature of 1350°C and hold for 12 hours. The efficacy of two-stage sintering on the microstructure and mechanical properties of the sintered samples were then evaluated. Addition of Ta2O5 combined with two-stage sintering were able to produce ZTA composites with enhanced grain size and mechanical properties compared to undoped ZTA composites. The samples with 0.3 vol% Ta2O5 content and above sintered at T1 ≥1450°C achieved density > 99% T.D., Vickers hardness > 19 GPa, Young’s modulus > 400 GPa and fracture toughness > 6 MPam1/2 when compared to undoped ZTA composites. This would enable production of ZTA with improved mechanical properties and lifespan ensuring the well-being of people suffering from osteoarthritis.

Newly developed Zinc-Tellurite glass system: An experimental investigation on impact of Ta2O5 on nuclear radiation shielding ability

In this paper, the nuclear shielding properties of newly fabricated Zinc-Tellurite glasses doped with Ta2O5 with a composition (25ZnO.75TeO2)100-x.(Ta2O5)x (x=0, 1, 2, 3 mol%) were studied. Ta2O5 doped Zinc-Tellurite glasses prepared by the traditional melt quenching method. The mass attenuation coefficients were achieved for prepared glasses at 0.081-0.383 MeV photon energies employing experimental transmission measurements, which were performed with 3 Ci Ba-133 point source and Ultra Ge detector. The experimental results were compared with simulated MCNPX and theoretical WinXCOM data. Moreover, another important nuclear shielding parameters such as mass attenuation coefficient, half value layer, effective atomic number, effective electron density, equivalent atomic numbers, alpha and proton projected ranges, mass stopping power in the protection of gamma, neutron, alpha and proton radiation were calculated. In addition, buildup factors of investigated glasses were determined by using the G-P fitting method. Moreover, effective removal cross section ΣR and transition factors were determined. According to the results, the addition of Ta2O5 to the glass samples has a positive effect on the performance of nuclear shielding effects of the glass samples. It can be concluded that ZTT3 glass sample with the highest Ta2O5 contribution has excellent nuclear radiation shielding ability among the other fabricated glass samples.

Effect of hydroxyapatite and Ag, Ta2O5 or CeO2 addition on the properties of ultrafine-grained Ti31Mo alloy

In the present study, the crystal structure, microstructure, mechanical and corrosion properties of bulk Ti31MoxHA composites (x = 0, 2.5, 5 and 10 wt %) were investigated. The sintering of Ti31MoxHA powders led to the formation of a bulk composite with grain size of approx. 1 μm. All these composites have elastic modulus lower than CP microcrystalline α-Ti, and their hardness is two times higher. The ultrafine Ti31Mo5HA composite was more corrosion resistant in Ringer solution than the bulk Ti31Mo alloy. Surface wettability measurements revealed the higher surface hydrophilicity of the bulk ultrafine-grained Ti31Mo10HA sample in comparison to microcrystalline Ti sample. Ti31Mo5HA composites with the addition of 1 wt % Ag, 2 wt % Ta2O5 or 2 wt % CeO2 were synthesized, too. The antibacterial activity of Ti31Mo5HA composite containing silver (Ag), tantalum (V) oxide (Ta2O5) or cerium (IV) oxide (CeO2) against Staphylococcus aureus was studied. In vitro bacterial adhesion, study indicated a significantly reduced number of S. aureus on the bulk ultrafine-grained Ti31Mo5HA-Ag (Ce2O3) plate surfaces in comparison to microcrystalline Ti plate surface. Ultrafine-grained Ti31Mo5HA - Ag or CeO2 biomaterials can be considered to be the future generation of medical implants.

Charge compensation and electrical characteristics of Ta2O5–doped SnO2–CoO ceramics

We investigated the effect of pentavalent donor dopant Ta2O5 on microstructure development, electric and dielectric characteristics of SnO2–CoO based ceramics. Already low additions of Ta2O5 (0.05 mol%) effectively reduce the porosity, improve densification and dielectric permittivity and trigger a 3–fold increase in SnO2 growth rate. Rietveld analysis shows that the amount of Co2SnO4 spinel phase drops with the addition of Ta2O5 due to incorporation of Co2+ and Ta5+ into SnO2 structure. With higher additions, however, Ta2O5 segregates to the grain boundaries and hinders SnO2 grain growth, which in turn improves electrical properties. TEM/EDS analysis shows that above 0.5 mol% of Ta2O5 the Co:Ta ratio in SnO2 grains is constant 1:2, which means that a twice lower amount of Ta5+ is incorporated in the SnO2 structure compared to the Nb2O5-doped SnO2–CoO system. Accordingly, the following charge compensation mechanism is proposed: 3 Sn(IV)S˟n (IV) ⇋ Co(II)Sn ̎(IV) + 2 Ta(V)˙Sn (IV).

BNT‐based ferroelectric ceramics: Electrical properties modification by Ta2O5 oxide addition

AbstractDue to their superior piezo‐responses (strain S > 0.3%), bismuth sodium titanate (BNT)‐based relaxor ferroelectrics have received much attention. Compared to other chemical elements, tantalum (Ta) doping provides superior electro‐strain for these ferroelectrics, while the effect of Ta2O5 as oxide additive has been rarely reported. Herein, lead‐free piezoceramics of Bi0.5(Na0.72K0.22Li0.06)0.5TiO3‐xTa2O5 (BNKLT‐xTa2O5, x = 0‐0.015) are synthesized. We study the effects of Ta2O5 addition on the crystal structure, piezoelectric responses, dielectric properties, and ferroelectric properties of BNKLT ceramics. All of the ceramics exhibit a typical perovskite structure, and Ta2O5 diffuses into the BNKLT lattice to form a uniform solid solution. The addition of Ta2O5 can make the grains more regular and uniform, while excess Ta2O5 result in finer grains. The undoped BNKLT ceramics show good ferroelectric and piezoelectric properties (remnant polarization Pr = 22.5 μC/cm2 and piezoelectric coefficient d33 = 250 pC/N); however, the addition of Ta2O5 leads to an clear degradation in d33 and Pr. Meanwhile, the addition of an appropriate Ta2O5 amount leads to an increase in the electro‐strain, and the unipolar strain reaches 0.385% under 60 kV/cm for x = 0.003, together with a higher normalized strain (d33*=Smax/Emax) of 633 pm/V (x = 0.003). The enhanced strain behaviors can be attributed to the coexistence of the ferroelectric and relaxor states, and an excellent electrostriction coefficient Q33 (Q33 = S/P2) value of 0.038 m4C−2 is obtained under 60 kV/cm for x = 0.003.

Effect of Ta2O5 addition on thermophysical and mechanical properties of (Sm0.5Gd0.3Yb0.2)2Ce2O7 compounds

In this study, the (Sm0.5Gd0.3Yb0.2)2(Ce1−xTax)2O7+x oxides were obtained by high-temperature solid-state sintering. The phase lattice, micro-structure, thermal-physical and mechanical performances of samples were examined. The synthesised compounds exhibit a single fluorite-type lattice, and they also have relatively dense microscopic structures. The differences in atomic weight and ionic radius between the solute and host kations enable a reduction of thermal conductivity of bulk samples. The reduced thermal expansion coefficient and the elevated elastic modulus are ascribed to the lower ion-radius of Ta5+ compared to Ce4+. The addition of “soft” Ta2O5 reduces the micro-hardness and increases the fracture toughness. The presented results herein provide an effective approach to ameliorate the fracture toughness of ceramics for thermal barrier coatings.

Enhanced rate capability due to highly active Ta2O5 catalysts for lithium sulfur batteries

The heterogeneous catalysis is widely recognized to promote polysulfide fragmentations can play a key role for the rate capability enhancement of lithium sulfur batteries (LSB). In this study, we report the most active catalysts (Ta2O5) for LSB which showed an enhanced rate capability (914 mAh g−1 at 5 C) in comparison with the previously reported catalysts, TiN (865 mAh g−1 at 5 C). The addition of Ta2O5 into the carbon-coated separator facilitates the chemical disproportionation of reaction intermeditates, Li2S4 into Li2S8 and Li2S effectively, which leads to the greatly lengthened second plateau in discharge profile. The heterogeneous catalysis of Ta2O5 is clearly verified with the UV–Vis spectra directly showing the change of Li2S4 concentration and the battery performance tests without any active elemental sulfur.

The synthesis and characterization of zinc-tellurite semiconducting oxide glasses containing Ta2O5

A series of zinc-tellurite oxide glasses based on (25ZnO.75TeO2)y.(Ta2O5)x (y = (100−x)%) system with different compositions of Ta2O5 (x = 0–7 with increment of 1% mole) have successfully been synthesized by the conventional melt-quenching technique and their structural, optical, thermal and some physical properties were determined. For this purpose, structures of the synthesized glasses were investigated using XRD, FTIR-ATR and DSC. Strong absorption bands that were found within the range of 760 cm−1 and 570–670 cm−1 were observed as the stretching vibrations mode of [TeO3] and [TeO4], respectively. Direct and indirect optical band gaps were calculated according to Tauc plot. It is found that addition of Ta2O5 to ZnO–TeO2 glass network increases the glass transition temperature (Tg), crystallization temperature (Tc), thermal stabilities (ΔT) and also density and molar volume. The measured values of electrical conductivity and resistivity using 4 probe method, and changes of the refractive index, have also been examined in this paper.

Surface and bulk crystallization of Ba1-xSrxZn2Si2O7 from glasses in the system BaO/SrO/ZnO/SiO2 doped with Nb2O5 or Ta2O5

Stoichiometric 0.5 BaO·0.5 SrO·2 ZnO·2 SiO2 glass was doped with 5 mol% Nb2O5 or Ta2O5. The effect of these additives on the crystallization behavior was studied using thermal analyses, X-ray diffraction, as well as scanning electron microscopy including elemental analyses. The addition of Nb2O5 or Ta2O5 significantly increases the glass stability enabling the preparation of crystal-free BaO·SrO·ZnO·SiO2 glasses with almost stoichiometric composition. Besides the desired main crystal phase Ba1-xSrxZn2Si2O7, also alkaline earth tantalates and niobates as well as Zn2SiO4 are observed. The Nb-containing glass shows solely surface crystallization, whereas in the Ta-containing glass, additionally numerous barium tantalate crystals precipitate in the bulk acting as seeds for the nucleation of Ba1-xSrxZn2Si2O7. If the surface crystallized layer of Ba1-xSrxZn2Si2O7 approaches such a barium tantalate crystal or gets close to it, then the crystallization of Ba1-xSrxZn2Si2O7 is initiated. It is supposed that these nucleation processes are notably facilitated by the stresses present in these glass-ceramics.

Influence of some thermally resistant transition metal oxides on emission features of Pr3+ ions in zinc borate glasses

This work consists of studies on the influence of thermally resistant transition metal oxides (TMO) viz., Ta2O5, Nb2O5 and ZrO2 on orange emission and NIR emission (1.3 μm) of Pr3+ ions in zinc borate glasses. Glasses of the composition 40ZnO–2Ta2O5/2Nb2O5/2ZrO2–56B2O3: 2Pr2O3 were synthesized by melt quenching technique. Optical absorption (OA), photoluminescence (PL) emission (in the wavelength region 500–2500 nm at λexc = 443 nm) and decay profiles of the two of the prominent transitions viz., 3P0 → 3H6 and 1G4 → 3H5 of Pr3+ ions were recorded. The spectra were analysed using standard J–O calculations and various radiative parameters associated with prominent transitions were estimated. Intensity of PL bands exhibited substantial increase due to addition of Ta2O5, Nb2O5 and ZrO2 to the host glass. Among the three studied glasses, ZrO2 mixed glasses exhibited the highest luminescence output. All the radiative parameters including quantum efficiency are observed to be the largest for ZrO2 mixed glasses. The results of IR spectral studies were also used for the analysis of emission spectra. The analysis indicated the degree of structural variations in the vicinity of luminescent Pr3+ ions is different due to addition of different transition metal oxides and such variations are found to be responsible for the changes in the PL output. Since a substantial improvement of PL emission corresponding to 1G4 → 3H5 transition is observed due to the admixing of TMOs, these glasses may be considered as the favourable candidates for the applications in telecommunications. Additionally, the emission in the green spectral region (which is predicted to be feeble under normal conditions) in the PL spectrum of Pr3+ ions is also found to be considerably increased and it is attributed to the transfer of energy from ZnO to Pr3+ ions in this region.

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.