Addition Of Bi2O3 Research Articles

Effect of Bi2O3 in Bi2O3–SrO–ZnO–B2O3 glass: Structural, mechanical, optical, and gamma ray shielding modifications

The effect of Bi2O3 in Bi2O3–SrO–ZnO–B2O3 glasses has been evaluated in this study. The density of the glasses increased from 5.127 g/cm³ to 6.214 g/cm³ as Bi2O3 concentration increased from 35 % to 50 %. The rise in molar mass and molar volumes points towards the opening of the network. The structural modifications increased the elastic moduli from 30.110 to 30.944 GPa for Young modulus; 17.653–17.860 GPa for bulk modulus; 13.242–13.662 GPa for shear modulus and 35.309–36.077 GPa for longitudinal modulus, respectively. The FTIR spectra indicate the conversion of BO4 to BO3 with increasing Bi2O3 concentration which accounts for the increase of the non-bridgingoxygens (NBOs). The band gap energy decreases from 3.165 to 3.020 eV with increasing Bi2O3 content. The transmission factors (TF) and other relevant parameters were evaluated for four different thicknesses of the glasses (0.5, 1, 1.4 and 2 cm). The 0.5 cm thick glass retained the highest TF when compared to other thicknesses. The TF for 0.5 cm thick glass is about 70 %, and drops to about 20 % for 2 cm thickness, which confirms that at 2 cm thickness, the glass materials shield better than 0.5, 1 and 1.4 cm. Furthermore, the addition of Bi2O3 causes a decrease in TF, so the glass with a high Bi2O3 content shields gamma radiation better than those with a low Bi2O3 content. The half value layer (HVL) values reduce as the Bi2O3 content is increased at all examined energies, confirming that the glass sample with highest Bi2O3 content has the superior shielding capability compared to the remaining examine glasses.

Enhanced multiferroic properties of NZCFO-BNFSO composites: Synthesis, characterization, and performance analysis

The structural and multiferroic properties of xNi0.24Zn0.58Cu0.18Fe2O4(NZCFO)-(1-x)Bi0.9Nd0.1Fe0.95 Sc0.05O3(BNFSO) are explored in this paper. Bi2O3 additives significantly lower the sintering temperature of the composites. The XRD analysis validates the coexistence of hexagonal perovskite BNFSO and spinel NZCFO phases. The FESEM images illustrate an almost homogeneous amalgamation of the BNFSO and NZCFO grains. The real part of initial permeability and the relative quality factor increases with NZCFO contents in the composites. The maximum permeability is observed for the composite with 80 % ferrite content. The ferroelectric BNFSO exhibits antiferromagnetic behavior and with the increase in NZCFO the saturation magnetization increases significantly. The dielectric constant confirms typical dielectric dispersion at low frequencies because of Maxwell–Wagner space charge polarization. The P-E hysteresis measurement reveals that the composite with 40 % ferrite content exhibits the highest loop area and hence a large energy storage capacity. Incorporating BNFSO and NZCFO into the composite boosts the multiferroic properties, which might be a suitable alternative to single-phase multiferroics.

Preparation of high-performance Bi-YG ferrite based on LTCC technology and theoretical analysis of its sintering mechanism

In the preparation process of Microwave Multi-Chip Module (MMCM), it is necessary to simultaneously sinter both microwave medium (ferrite) and silver electrodes. Hence, this necessitates keeping the sintering temperature below the melting point of silver (961 °C). An excessively low sintering temperature would significantly impair the electromagnetic properties of the ferrite material. To address this concern, this study synthesizes Bi-YIG (Y3-xBixFe5O12, x = 0–1.0) ferrites with optimized characteristics, including low ferromagnetic resonance line-width (ΔH) and high saturation magnetization (Ms), at 945 °C using Low Temperature Co-fired Ceramic (LTCC) technology. The mechanism of low-temperature liquid phase sintering, facilitated by a fluxing agent, was investigated using a theoretical model. The addition of Bi2O3 fluxing agent was found to reduce the reaction activation energy, disrupt the chemical reaction equilibrium, and promote low-temperature liquid phase sintering, thus lowering the critical sintering temperature below the melting point of silver. Furthermore, optimal bismuth content was identified to regulate the dynamic balance between grain growth and boundary diffusion, suppressing abnormal grain growth and enhancing the electromagnetic properties of the ferrite. This exploration, leveraging LTCC technology, may offer valuable insights for enhancing the overall performance of MMCMs.

Enhancement of radiation shielding properties in BaTiO3 added with Bi2O3 at the energy range of 356keV -1333keV

Abstract The investigation on the radiation shielding properties of BaTiO3-xBi2O3 with (x=0, 2, 4, 6, 8 %) ceramic samples has been discussed in this paper. This study targeted especially on the radiation shielding properties such as tenth value layer (TVL) and effective electron density (Neff) by including density of sample as one of the parameters. The prepared ceramic samples radiation shielding properties were quantified with help of radioactive sources Ba133, Na22, Cs137, and Co60 at the energies 356keV, 511keV, 1173keV, 1275keV and 1333keV. The obtained experimental values compared with theoretical values by using Phy-X/PSD software. Obtained results revealed that, attenuation abilities improved due to addition of Bi2O3 at different concentration to BaTiO3 causes the rise in density of ceramic samples from 5.483 to 5.498g/cm3. S1 sample has maximum TVL value found at 10.098cm and sample S4 noticed with lowest value 9.842cm at 1333keV. The maximum Neff value recorded as 2.72 at 1333keV for sample S4 which indicating promising radiation shielding abilities.

Fabrication of ZnO/ Bi2O3/PVA coated glass for X-ray detection and measurement

Electrospun ZnO/Bi2O3/PVA-coated glass samples were fabricated using electrospinning method, with varying ZnO molarities (0 M, 5 M, and 7 M) and Bi2O3 weight percentages (wt%) to assess their potential for x-ray detection and measurement. Sample morphology and elemental composition analysis revealed well-distributed nanofiber strands on the glass substrate, with even dispersion of elements within the nanofiber across all samples. The effective atomic number (Zeff) of the sample is consistently enhanced with the addition of Bi2O3 and higher ZnO molarity, where sample with 7 wt% Bi2O3 own a greater Zeff value (41.56–44.12) than sample with 5 wt% Bi2O3 (37.22–40.54). All samples except Sample A0 and B0 exhibited strong absorbance between wavelength range of 360 nm–400 nm. Sample A0 and B0 yielded energy band gaps (Eg) of 2.39 eV and 2.37 eV, respectively, whereby samples with ZnO exhibit energy gaps of Eg = 3.29 eV (Sample A1), Eg = 3.27 eV (Sample A2), Eg = 3.25 eV (Samples B1 and B2). All samples underwent x-ray exposure at various tube voltages (40–60 kVp) to assess their attenuation ability for x-ray detection and measurement. Sample B2 (5 wt% Bi2O3 and 7 M ZnO) exhibited the most favorable linear response, while Sample B1 (5 wt% Bi2O3 and 5 M ZnO) displayed favorable energy dependency. Thus, the electrospun ZnO/Bi2O3/PVA-coated glass with these compositions are proposed as potential dosimetry material due to their favorable linear response and energy dependency characteristics.

Low temperature fabrication of Ba0.9Cs0.3Cr2.1Ti5.9O16 ceramic waste form for cesium immobilization using Bi2O3 as sintering aid

In this paper, we present a productive low-temperature fabrication of Cs-hollandite ceramics by adding Bi2O3 as a sintering aid to achieve high cesium retention. The effects of Bi2O3 addition on the phase composition, crystal structure and aqueous stability of the stoichiometric Ba0.9Cs0.3Cr2.1Ti5.9O16 ceramic waste form were investigated. It was found that adding Bi2O3 can effectively reduce the sintering temperature and promote densification of Cs-containing hollandite products. The Cs-hollandite ceramic with 2 wt% Bi2O3 sintered at 1000 °C showed a single phase with > 98 % cesium retention, which was ∼ 200 °C lower and ∼ 11 % retention rate higher than those of reported Cs-bearing hollandite. Moreover, the leached sample remained stable tetragonal structure, the LRCs was in the order of 10-3 g·m-2·d-1 after 28 days and the leaching indexes > 8, exhibiting good aqueous stability. This route can be considered as a promising solution to prevent cesium loss for incorporating the cesium waste in ceramic hosts.

Bioactivity of radiopaque 45S5 bioactive glass with progressive additions of Bi2O3: A dissolution study under static conditions

The integration of bioactive glasses (BGs) into hard tissues in in-vivo models can be evaluated through X-ray radiographs. The image contrast plays an important role and should be enhanced to improve accurate minimal invasive diagnostics of the performance of BGs containing implants after surgery. The present work shows the effect of the progressive addition of Bi2O3 (up to 12.2 wt%) on the structure, thermal properties, radiopacity, and bioactivity of 45S5-like BG obtained by quenching of the melt prepared from oxide precursors. The BG chemical composition, phase composition, structure, chemical state, thermal properties, and radiopacity were respectively investigated by X-ray fluorescence (XRF), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and radiopacity analysis according to the ISO13116:2014 norm. The bioactivity of the glasses was monitored by immersing them in a simulated body fluid (SBF) under static conditions. The apatite formation ability and ion concentration in SBF after 3, 7, 14, and 21 days were investigated by XRD, scanning electron microscopy (SEM), inductively coupled plasma optical emission spectroscopy (ICP-OES), and ICP mass spectrometry (ICP-MS). All samples were found to be X-ray amorphous. Simultaneous formation of [BiO3] and [BiO6] units is noted in the BG. The glass radiopacity increased up to 1.8 and 4.2 times compared to the reference glasses without Bi2O3. Bi2O3 additions in the glass slow down the formation of apatite-like structures as a result of the network forming role of [BiO3] and [BiO6] units in the BG. Nevertheless, the BGs with the 12.2 wt % Bi2O3 still shows the ability to form apatite deposits after 7 days of immersion in simulated body fluid (SBF).

Effect of glass frit composition on reliability of silver paste metallization in crystalline silicon solar cells

Glass frit used in conductive silver (Ag) pastes has a significant impact not only on the electrical performance but also on the long-term reliability of metallized electrodes in crystalline silicon (c-Si) solar cells. Here, we investigated the role of compositional changes on the metallization process of silver pastes by adjusting the SiO2, ZnO, Li2O, or Bi2O3 in lead borate glass melts, and performed damp heat (DH) tests in an acidic damp heat environment. It was found that the addition of Bi2O3 resulted in a decrease in conversion efficiency (Eta) of only 6.44% after the cell was treated with dilute acetic acid. Under scanning electron microscopy (SEM), it was observed that the cell with this glass frit had minimal changes in the microstructure of its silver-silicon contacts and silver electrodes. This finding helps to improve the performance and stability of solar cells in harsh environments.

Influence of ZnCl2 on gamma attenuation and radiation shielding of tellurite glasses containing Bi2O3 and B2O3

This paper investigates the influence of ZnCl2 on the gamma attenuation and radiation shielding properties of tellurite glasses incorporating Bi2O3 and B2O3. Employing Geant4 simulation and XCOM program, the study explores the impact of varying ZnCl2 content on different gamma attenuation parameters such as linear attenuation coefficient (μ), radiation protection efficiency (RPE), effective atomic number (Zeff), and HVL. Moreover, the relation between these factors and the density of the studied glass system is discussed in details. It is found that the incremental addition of Bi2O3 significantly enhanced the photon attenuation properties of the tellurite glasses involved. The maximum Zeff values are observed at the low energy region between 0.015 and 0.1 MeV with the values of 53.016, 60.133, 65.950, 70.370, and 73.791 for the glass samples namely TBBZC1, TBBZC2, TBBZC3, TBBZC4, and TBBZC5, respectively. Furthermore, the HVL values fall between 0.0016 cm and 4.3546 cm indicates that the current glass system can be utilizes for gamma shielding applications. The results provide insights into the potential enhancement of radiation shielding efficiency in tellurite glasses, contributing valuable knowledge for the development of advanced materials in nuclear safety applications.

Enhancing grain boundary contributions to improve the dielectric properties of (In0.5Nb0.5)0.05Ti0.95O2 ceramics by Bi aided sintering

The internal barrier layer capacitance effect substantially contributes to the colossal permittivity in In and Nb co-doped TiO2 (INTO) ceramics. Therefore, enhancing grain boundary density and ceramic compactness can efficaciously reduce their low-frequency dielectric loss. In this investigation, Bi2O3 addition was utilized to aid sintering and refine grains for INTO ceramics. The results reveal that Bi-doped INTO ceramics, in contrast to their undoped counterparts, exhibit a more refined and compact grain structure with a significant increase in the quantity of grain boundaries. Moreover, a noticeable reduction in low-frequency dielectric loss from above 0.1 to below 0.05 and enhanced frequency stability of permittivity from below 10 Hz to approximately 10 kHz were observed, along with a decrease in the sintering temperature to 1300 °C. In comparison to undoped INTO ceramics, Bi doping also enhances the withstand voltage capability by a factor of 1.5–4 for Bi-doped INTO ceramics. However, as the sintering temperature of Bi-doped INTO ceramics increases and the grain size enlarges, their breakdown voltage gradually decreases, but the non-linear coefficient of current-voltage characteristics progressively increases. Analysis of complex impedance spectra confirms that the increased grain boundary density and resistance in Bi-doped INTO ceramics is the primary factor for the enhanced dielectric properties and withstand voltage capability.

A-site disorder induced ferroelectric to relaxor phase transition of Na(Nb0.75Ti0.25)O3 ceramics by Bi3+ for ultra-high energy storage properties

The present work introduces a new insight into effect of A-site disorder to develop the energy storage properties of Na(Nb0.75Ti0.25)O3 ceramic. Lead-free (Na1-xBix)(Nb0.75Ti0.25)O3 (x = 0.0, 0.05 and 0.1) (abbreviated as NNTBx) ceramics were synthesized using solid-state reaction technique. The introduction of Bi3+ shown a significant effect into the crystal structure, dielectric, ferroelectric and energy storage properties of NNT ceramics. The addition of Bi2O3 induced ferroelectric to relaxor phase transition with psedu-cubic crystal structure at 0.1. Significant inhibits of grain size to sub-micrometer has been achieved at 0.1 sample due to lower ionic radius of Bi+3 (1.34 Å, CN=12) to the ionic radius of Na1+ (1.39 Å, CN=12). Meanwhile, the dielectric constant increased from 300 to 1500 when the Bi3+-content increased from 0.0 to 0.1. Effectively increasing in maximum polarization (Pmax) and significant reducing in remnant polarization (Pr) resulting in increasing ΔP (Pmax – Pr) has been obtained at 0.1 content of Bi2O3. This enhancement is attributed to hybridization between Bi3+ 6Pand O2− 2P instead of Na1+ 2S and O2− 3S orbitals. On the other hand, the substitution of monovalent (Na1+) by trivalent (Bi3+) lead to create sodium vacancies into the A-sites of NNT lattice subsequently reducing the Pr value. The tolerance factor (τ) decreased from 0.955 to 0.953 when Bi2O3 increases from 0.0 to 0.1 indicate increasing the cations disorder, charge misfit and relaxor degree of NNT ceramics. The sample with 0.1 of Bi2O3 demonstrate remarkably high energy storage density (Wrec = 17.5 J/cm3), and high relatively energy storage efficiency (n = 80 %) at ultra-high dielectric breakdown strength (Eb = 700 kV/cm). Partially, (NNTB0.1) exhibit an outstanding stability of energy storage properties in terms of temperature (25 to 150 °C) and frequency (2–50 Hz). The variation of Wrec and n were observed about 1 % within the whole range of applied temperature and frequency. These results imply the high potential of (Na0.9Bi0.1)(Nb0.75Ti0.25)O3 ceramic in temperature-stable advanced pulsed power capacitor applications.

Synthesis of The Cu(II)-doped TiO2/Bi2O3 as a Photocatalyst for Rhodamin B Degradation Under Visible Light Ilumination

The Cu(II)-doped TiO2 and Cu(II)-doped TiO2 /Bi2O3 compound have been synthesized using the sol gel method with titanium tetraisopropoxide (TTIP) as the TiO2 precursor and Cu(NO3)2.3H2O as the Cu(II) dopant was carried out at various concentration of 0.075%; 0.250% and 1.000%, as well as Bi(NO3)3.5H2O as a Bi2O3 precursor. Based on characterization using the DRSUV-Vis spectrophotometric method with data analysis using a tauch plot, it is known that the band gap energy of Cu(II)-doped TiO2 is 2.89 eV; 2.72 eV; 2.54 eV. The addition of Bi2O3 to Cu(II)-doped TiO2 (1%) causes a decrease in the band gap from 2.54 to 2.18 eV which is equivalent to a wavelength of 567 nm. IR spectrophotometry spectra analysis shows a shift in Ti-O absorption towards smaller wave numbers. Characterization by the XRD method shows that 1% Cu(II)-doped TiO2 /Bi2O3 has an anatase phase with a crystallite size of 24 nm. Photocatalysis activity test on the degradation of rhodamine B solution at a concentration of 10 ppm, under visible light illumination for 180 minutes was able to degrade up to 85.85%.

Enhanced thermoelectric performance of Sr0.875La0.1TiO3-δ based composites through Bi-rich inclusions in internal and external reduction environments

The electrical transport performance of bulk SrTiO3 thermoelectric materials can be optimized by incorporating uniformly dispersed conductive inclusions. Herein, the impact of Bi2O3 addition on the thermoelectric properties of La-doped strontium titanate composite nano Ti powder (Sr0.875La0.1TiO3-δ/20 wt% Ti) has been examined. During the sintering process, Bi2O3 gradually transforms into a liquid phase to facilitate Redox reactions with nano Ti and mass transfer, followed by reduction and transformation into Bi–Bi2O3 particles that precipitate at grain boundaries. The presence of nanoscale Bi-rich phases reduces carrier transport barriers at grain boundaries and enhances phonon relaxation time associated with grain boundary scattering. Ultimately, the sample containing 10 wt% bismuth oxide exhibits the lowest lattice thermal conductivity and the highest weighted mobility. This led to a maximum power factor of 498 μW/mK2 at 873 K and a maximum ZT value of 0.188 at 1073 K. This study presents a novel approach to decouple electroacoustic transport through the utilization of Redox reactions between multiple phases, offering valuable insights for the development of high-performance thermoelectric oxide composites.

Cd2+-enhanced the structure, electrical and magnetic properties of low-temperature sintered NiCuZn ferrites

Ferrite materials are urgently demanded in high-frequency miniaturized power electronics for their high electromagnetic properties and high electrical resistivity. However, traditional NiZn ferrites are faced with low resistivity and high loss at low-temperature sintering, which severely restrict their applications. In this study, CdO was substituted into Ni0.22Cu0.2Zn0.58Fe2O4 ferrites at a presintered stage to refine the grain size and to achieve superior performance at low-temperature sintering. Interestingly, the electrical, magnetic and gyromagnetic properties of the NiCuZn ferrites exhibited a strong dependence on the concentration of Cd2+ ions. The Cd2+ ions entered into the lattice and substituted for Fe3+ at the octahedral site. SEM image results showed that CdO-substituted NiCuZn ferrites for the first sintering stage possess inhibition of abnormal grain growth, which can effectively solve the problem of shrinkage and grain compaction of ferrite materials in LTCC technology. Furthermore, to promote the grain growth at low sintering temperature, the optimized Bi2O3 additives were added at final sintering stage. The resistivity of the optimized Cd2+ ions is significantly enhanced from 2.41 × 108 Ω cm to 8.51 × 108 Ω cm. Finally, the NiCuZnCd (x = 0.15)-1.2 wt% Bi2O3 ferrites with the highest densification possess ρ = 8.51 × 108 Ω cm, ε′ = 18, tan δε = 6.0 × 10−3, μ′ = 81, fr = 117 MHz, tan δμ = 4.8 × 10−2 and ΔH = 281 Oe. This work provides a new doping method for the design of the high frequency LTCC device.

Physical, mechanical, and gamma ray shielding properties of the Bi2O3–BaO–B2O3–ZnO–As2O3–MgO–Na2O glass system

Abstract This study provides insights into the effects of Bi2O3 on the physical, mechanical, and gamma ray shielding properties of Bi2O3–BaO–B2O3–ZnO–As2O3–MgO–Na2O glasses. The higher Bi2O3 concentrations result in increased density and molecular weight of the glasses. The molar volume also increases with higher Bi2O3 percentages, accompanied by a decrease in the average distance between boron atoms and a reduction in polaron radius and inter-nuclear distance. Electronegativity decreases and electronic polarizability increases with increasing Bi2O3 concentration, indicating higher electron-donating capacity and greater susceptibility to external electric field distortion. The elastic moduli exhibit a downward trend with increasing Bi2O3 concentration, indicating a decreased degree of elastic behaviour. The decrease in cross-linking is further supported by the reduction in Poisson’s ratio. The decrease in values of the hardness also indicates a decline in the stiffness and connectivity of the glass network. The linear attenuation coefficients (LACs) of three different glasses were obtained using Phy-X software in 0.015–15 MeV energy range. Also, the effective atomic numbers are calculated for the selected glasses. The LAC has the highest values for Bi21, indicating that the addition of Bi2O3 causes an improvement in the LAC.

Investigation on The Effect of Bismuth Concentration Towards Radiation Shielding Properties in Ag-embedded Borobismuthate Mixed Ionic Electronic Glass System

In this study, 20Li2O–xBi2O3–(79-x)B2O3–1Ag glasses for x=3,5,7,9, and 11 mol % glasses were prepared by using the melt quenching technique to investigate radiation shielding properties of the glasses using Phy-X/PSD simulation program at 15 keV to 15 MeV photon energy range. The radiation shielding parameters were carried out to determine the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half value layer (HVL), mean free path (MFP) and effective atomic number (Zeff). The results showed that the Bi2O3 addition has improved overall radiation shielding properties. The MAC of the glass system was increased as Bi2O3 concentration increased. The HVL showed that present glass better than standard commercial concretes as lower HVL value indicates better shielding where 11 mol % required a much smaller thickness than 3 mol %. Therefore, sample with highest bismuth content has the most effective radiation protective property. Smaller MFP is most preferable as it suitable for protection materials; indicated the 11 mol % is best candidate for radiation shielding. Lastly, the higher value in Zeff was contributed by higher atomic number of Bi over B; thus, enhanced protection performance.

Exploring the impact of Bi2O3 addition on the thermal properties and crystallization behavior of lead borosilicate glasses

Novel heavy-metal oxide glasses with different compositions, specifically (80-x)PbO– xBi2O3–10B2O3–10SiO2, where x ranges from 0 to 60 mol%, were synthesized using a conventional melt-quenching technique. The amorphous nature of these glasses was confirmed through X-ray diffraction analysis. Additionally, infrared spectra were obtained for the prepared samples to explore their structural characteristics. Differential thermal analysis was performed to investigate the characteristic temperatures of the glasses, including the glass transition temperature, melting temperature, onset crystallization temperature, and peak crystallization temperature. The addition of Bi2O3 shifts the characteristic temperatures to higher values and affects the crystallization process and phases formed. Parameters like ΔT, KH, and KSP are used to evaluate and quantify glass stability. Dilatometric measurements demonstrated that substituting PbO with Bi2O3 in the glass composition resulted in an increase in glass transition temperature and dilatometric softening temperature, as well as a decrease in the coefficient of thermal expansion. Furthermore, we determined the density and calculated the molar volume of the samples. These findings deepen our understanding of the thermal behavior, glass stability, and structure-property relationships in lead borosilicate glasses with Bi2O3, facilitating the development and customization of glass compositions with desired thermal and physical characteristics for specific applications.

Structural and gamma-ray attenuation of mixed former lead-free borophosphate glasses

Sodium borophosphate parent glass in conjugation with other derived samples containing adaptable amounts of bismuth oxide at the expense of phosphate partner was prepared via the ordinary melt-quenching technique. Synthesized samples were investigated using Fourier transforms infrared (FTIR) spectroscopy. The undercover or overlapped peaks were estimated using the deconvolution analysis technique (DAT). The collected IR spectra refer to the presence of combined PO4 and BO3+BO4 groups besides the presence of Bi–O vibrations upon the addition of Bi2O3. The assignments of the IR peaks are facilitated by the conduction of deconvolution processes. The density of the studied glass was estimated and some selected physical parameters including molar volume and packing density were calculated.Gamma-ray shielding competence of studied borophosphate glasses has been explored through user online friendly software (Phy-X/PSD) in combination with their abilities to act as shielding candidates as a function of Bi2O3 content. In addition, linear and mass attenuation coefficients (μm) combined with other physics parameters were calculated to assess the proper action of bismuth oxide in the shielding mechanism. Sample NABP10Bi enriched with Bi2O3 possessed the highest values of LAC, MAC, and Zeff. The HVL parameter followed the trend that was considered to be dependent on the bismuth oxide concentration.

INVESTIGATION OF THE PHASE FORMATION PROCESS
 DURING THE SYNTHESIS OF CERAMIC MATERIALS
 BASED ON MODIFIED YTTRIUM MANGANITE

The aim of this work is to establish the nature and sequence of phase formation processes in the synthesis of ceramic
 materials based on yttrium manganite using different manganese oxides and structure modifiers. Differential scanning calorimetry,
 X-ray phase analysis, and scanning electron microscopy were used as research methods in the work. The physicochemical
 and electrophysical properties of the obtained samples were determined. Samples of modified yttrium manganite
 were obtained by solid-phase sintering of the initial components at various temperature-time parameters of heat treatment.
 The influence of Bi2O3, CoO and TeO2 additives on the physicochemical and electrophysical properties of prototypes was
 studied. Regularities of the structure formation processes and phase composition of ceramic materials are established in
 relation to the composition of raw materials and the technological parameters of the synthesis of modified yttrium manganite.
 It has been established that the addition of oxides of the RO type contributes to a decrease in the degree of crystallization
 of the samples, as evidenced by a decrease in the intensity of the diffraction peaks of the crystalline phases. In this case,
 the qualitative composition of the phases practically does not change, but the proportion of the amorphous component in the
 structure of the material increases. Bi2O3 has the most effective modifying effect in the synthesis of yttrium manganite.
 Its addition into the composition of the raw mixture intensifies the process of formation of the yttrium manganite phase with
 a crystal size of 2–4 μm, which is confirmed by the results of DSC, XRD, and electron microscopy. The intensification of the
 crystallization process due to the addition of bismuth oxide is explained by the developed mechanism of liquid-phase sintering
 and the formation of a significant number of crystallization centers. The developed ceramic materials based on modified
 yttrium manganite have a set of electrophysical characteristics that make it possible to recommend them for the manufacture
 of various elements of electronic technology.

Hypersensitivity and nephelauxetic effect of Er3+ in bismuth tellurite glass system

The optical absorption and emission properties of 20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag glass system had been analyzed to investigate the hypersensitivity shift and its mechanism. According to the Covalent model, the hypersensitive shift indicated by the drop of F2 at x = 5 mol% can be attributed to charge transfer from O2– ligands to Er3+ ions meanwhile according to the Dielectric screening model, drop of F2 may due to Er3+ ions contraction. The dynamic coupling mechanism was used to explain hypersensitivity transition probabilities in non-centrosymmetric systems. The addition of Bi2O3 may modify the site symmetry of Er3+ ions and oxygen to a high asymmetry τ2, resulting in an asymmetrical electron distribution, thus increasing Er-O covalency, as shown by the maximum Ω2 value at x = 5 mol%. The Er3+ ions site symmetry was investigated using Hamiltonian crystal field fitting in the frame of the D4 point symmetry model, which yielded maximum crystal field strength Nv at x = 5 mol%, indicating low point symmetry distortion of the Er3+ ions site symmetry.