Вісники та науково-технічні збірники, журнали
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Item Sensitive elements of temperature converters based on HfNi1-xCuxSn thermometrical material(Видавництво Львівської політехніки, 2023-02-28) Krayovskyy, Volodymyr; Rokomanyuk, Mariya; Luzhetska, Nataliya; Pashkevych, Volodymyr; Romaka, Volodymyr; Stadnyk, Yuriy; Romaka, Lyubov; Horyn, Andriy; Lviv Polytechnic National University; Ivan Franko National University of LvivThe results of experimental studies of sensitive elements of temperature transducers based on semiconductor thermometric material HfNi1-xCuxSn are presented. Thermometric materials HfNi1-xCuxSn, x=0.01–0.10, were produced by fusing a charge of components in an electric arc furnace with a tungsten electrode (cathode) in an atmosphere of purified argon under a pressure of 0.1 kPa on a copper water-cooled base (anode). Heat treatment of the alloys consisted of homogenizing annealing at a temperature of 1073 K. The samples were annealed for 720 hours. in quartz glass ampoules vacuumed to 1.0 Pa in muffle electric furnaces with temperature control with an accuracy of ±10 K. Diffraction data arrays were obtained on a STOE STADI-P powder diffractometer (Cu Kα1 radiation), and the structural characteristics of HfNi1-xCuxSn were calculated using the Fullprof program. The chemical and phase compositions of the samples were monitored using metallographic analysis (scanning electron microscope Tescan Vega 3 LMU). The thermoelectric pair platinum-thermometric material Pt-HfNi0.99Cu0.01Sn was the basis of the thermoelectric converter. Modeling of thermometric characteristics of sensitive elements of thermotransducers in the temperature range of 4.2– 1000 K was carried out by the full potential linearized plane wave method (Full Potential Linearized Augmented Plane Waves, Elk software package). The results of experimental measurements served as reference currents for modeling characteristics. X-ray phase analysis showed the absence of traces of extraneous phases in the diffractograms of the studied samples of HfNi1-xCuxSn thermometric materials, and the microprobe analysis of the concentration of atoms on their surface established the correspondence to the original composition of the charge. Refinement of the crystal structure of HfNi1-xCuxSn showed that the introduction of Cu atoms orders the structure, which makes it stable, and the kinetic characteristics are reproducible during thermocycling at temperatures T=4.2–1000 K. Ordering the structure of the thermometric material HfNi1-xCuxSn leads to changes in the electronic structure. At the same time, the number of donors decreases – Ni leaves the Hf position, and the substitution of Ni atoms for Cu leads to the generation of structural defects of the donor nature (Cu atoms contain more 3d-electrons), and another donor band εD Cu will appear in the band gap εg. For the sensitive elements of thermoconverters at Cu impurity concentrations x=0.005 and x=0.01, the temperature dependences of the specific electrical resistance ln(ρ(1/T)) contain activation areas, which is consistent with the results of electronic structure modeling. This indicates the location of the Fermi level εF in the band gap εg, and the negative value of the thermopower coefficient α(T) at these temperatures specifies its position – near the conduction band εC. The value of the activation energy from the Fermi level εF to the bottom of the conduction band εC was calculated. For the base semiconductor n-HfNiSn, the Fermi level εF lies at a distance of εF=81 meV from the co εC conduction band εC, and in the sensitive elements of thermoconverters with concentrations of HfNi0.995Cu0.005Sn and HfNi0.99Cu0.01Sn – at distances of εF=1 meV and εF=0.3 meV respectively. Therefore, an increase in the concentration of the Cu donor impurity leads to a rapid movement of the Fermi level εF to the bottom of the conduction band at a rate of ΔεF/Δx≈81 meV/%Cu. The impurity concentration x=0.01 is sufficient for the metallization of the conductivity of sensitive elements of HfNi1-xCuxSn converters at low temperatures. This is possible if the Fermi energy εF is close to the conduction band εC (εF=0.3 meV), which simplifies the thermal ionization of donors and the appearance of a significant number of free electrons. However, this impurity donor zone still does not intersect with the bottom of the conduction band εC. At concentrations of the Cu donor impurity in HfNi1-xCuxSn, x=0.2–0.07, the high-temperature activation regions disappear on the temperature dependences of the resistivity ln(ρ(1/T, x)), which indicates the movement of the Fermi level εF from the band gap εg to the conductivity εC. At the same time, the values of specific electrical resistance ρ(T, x) increase monotonically with increasing temperature), and the scattering of electrons by phonons determines the conductivity of sensitive elements of thermotransducers based on the thermometric material HfNi1-xCuxSn. The metallization of the electrical conductivity of the thermometric material HfNi1-xCuxSn at concentrations x>0.01 is accompanied by a rapid decrease in the values of the thermopower coefficient α(x, T). Thus, if in n-HfNiSn at a temperature of T=80 K, the value of the thermal erst coefficient was αx=0=–178 μV/K, then in the HfNi0.93Cu0.07Sn material αx=0.07=–24 μV/K. The results of the kinetic properties of HfNi1-xCuxSn are consistent with the conclusions of structural and energetic studies. The simulation of the conversion functions of the sensitive elements of the resistance thermometer and the thermoelectric converter in the temperature range of 4.2–1000 K was carried out. As an example, the conversion functions of the thermoelectric pair Pt-HfNi0.99Cu0.01Sn are given. The ratio of change of thermo-EMF values to the range of temperature measurements in thermocouples is greater than all known industrial thermocouples. However, due to the metallization of the conductivity of the thermometric material HfNi1-xCuxSn, x>0.01, the temperature coefficient of resistance (TCR) of the obtained resistance thermometers is greater than the TCR of metals, but is inferior to the value of TCR of sensitive elements made of semiconductor materials.Item Investigation of sensitive elements of temperature transducers based on thermometric material Lu1-xScxNiSb(Видавництво Львівської політехніки, 2022-02-28) Pashkevych, Volodymyr; Krayovskyy, Volodymyr; Haranuk, Petro; Romaka, Volodymyr; Stadnyk, Yuriy; Romaka, Lyubov; Horyn, Andriy; Lviv Polytechnic National University; Ivan Franko National University of LvivThe results of experimental studies of sensitive elements of temperature transducers based on semiconductor thermometric material Lu1-xScxNiSb, x = 0.01–0.10, are presented. Thermometric materials Lu1-xScxNiSb were made by fusing a mixture of components in an electric arc furnace with a tungsten electrode (cathode) in an atmosphere of purified argon under a pressure of 0.1 kPa on a copper water-cooled hearth (anode). Heat treatment of alloys consisted of homogenizing annealing for 720 h in vacuumed to 1.0 PA at a temperature of 1073 K. Arrays of diffraction data of X-ray diffraction studies were obtained on a powder diffractometer STOE STADI-P, and using the program Fullprof calculated structural characteristics. The chemical and phase compositions of the samples were monitored by metallographic analysis (scanning electron microscope Tescan Vega 3 LMU). The basis of the sensitive element of the resistance thermometer on Lu1-xScxNiSb materials is polycrystalline samples in the form of rectangular parallelepipeds with a size of 0.5×0.5×5 (mm3), to which the contacts are made of copper and/or platinum wire. Experimental measurements of electrical resistance values were performed using the four-contact method, and the values of the thermopower coefficient by the potentiometric method concerning copper and/or platinum. The thermoelectric pair platinumthermometric material was the basis of the thermoelectric converter. Modeling of thermometric characteristics of sensitive elements of the thermometer of resistance of the thermoelectric converter is carried out by a full potential method of linearized plane waves (Full Potential Linearized Augmented Plane Waves, Elk software package). The results of experimental measurements served as reference currents in modeling the characteristics.X-ray phase analysis showed the homogeneity of the studied samples of thermometric materials Lu1-xScxNiSb, as evidenced by the absence of traces of extraneous phases on the diffractograms. The dependences of the period of the unit cell a(x) Lu1-xScxNiSb are not linear, which indicates more complex structural changes than the one-act substitution of the Lu atom by Sc. Measurements of the values of the specific magnetic susceptibility χ (T, x) were performed by the relative Faraday method at T = 273 K using a thermogravimetric installation with an electronic microbalance EM-5-ZMP in magnetic fields up to 10 kGs. Experimental studies of the specific magnetic susceptibility of χ(x) sensitive elements have shown that the samples at all concentrations are Pauli paramagnetics, and the value of χ(x) is determined by the electron gas. In this case, the values of the magnetic susceptibility χ(x) are proportional to the density of electronic states at the Fermi level g(εF). In the area of concentrationsx = 0–0.02, the values of magnetic susceptibility χ(x) undergo insignificant changes, which indicates small changes in the concentration of current carriers. At a concentration x > 0.02 there is a rapid increase in the density of electronic states at the Fermi level g(εF), indicating an increase in the concentration of free current carriers. The presence of high-temperature activation sites on the temperature dependences of the resistivity ln(ρ(1/T)) for all Lu1- xScxNiSb samples indicates the location of the Fermi level εF in the band gap εg of the semiconductor, and positive values of the thermopower coefficient α(T) specify its position – near the valence band εV. The main carriers of electric current are holes. The nature of the behavior of the resistivity ρ (x, T) Lu1-xScxNiSb at all temperatures also corresponds to the results of modeling the kinetic properties. The fact that in the range of concentrations x = 0–0.04 the values of the resistivity ρ (x, T) Lu1-xScxNiSb change slightly at all temperatures indicates a significant advantage of the concentration of holes over electrons. This is indicated by positive values of the thermopower coefficient α (x, T). At concentrations x ≥ 0.04, the resistivity increases rapidly, which is due to the appearance of donors, which partially compensate for the acceptors, which reduces the concentration of free holes, and, as a result, we have an increase in the resistance. The behavior of the thermopower coefficient α (x, T) Lu1-xScxNiSb is adequate. The appearance and increase in the electron concentration are accompanied by an increase in the thermopower coefficient α (x, T). At a concentration of x ≈ 0.07, the dependence of the thermopower coefficient contains an extremum, and then the values of the thermopower coefficient rapidly decrease at a temperature of T = 80 K and concentrations at x ≈ 0.1. Electrons are already the main current carriers. This is indicated by the negative values of the thermopower coefficient. It was experimentally established that at the concentration range x = 0–0.07 the Fermi level velocity εF from the valence band εV is ΔεF/Δx = 4.9 meV /% Sc, and at the concentration, x ≥ 0.07 – ΔεF/Δx = 11.2 meV /% Sc. The presence of a difference in the velocities of the Fermi level εF indicates different rates of generation of acceptors and donors: at a concentration of x ≥ 0.07, the concentration of donors increases ~2 times faster than at the site x = 0–0.07. The functions of conversion of sensitive elements of resistance thermometer and thermoelectric transducers in the temperature range 4.2–1000 K are modeled. The ratio of the change in the values of the thermopower coefficient to the range of temperature measurements in thermocouples is greater than all known industrial thermocouples. In addition, the temperature coefficient of resistance (TCR) of the obtained resistance thermometers is higher than the TCR of metals but is inferior to the value of TCR of sensitive elements made of traditional semiconductors. At the same time, none of the known resistance thermometers based on traditional semiconductors provides stable characteristics at temperatures of 4.2÷1000 K.Item Characteristics of thermometric material Lu1-xScxNiSb(Видавництво Львівської політехніки, 2022-02-28) Pashkevych, Volodymyr; Krayovskyy, Volodymyr; Horpenyuk, Andriy; Romaka, Volodymyr; Stadnyk, Yuriy; Romaka, Lyubov; Horyn, Andriy; Romaka, Vitaliy; Lviv Polytechnic National University; Ivan Franko National University of Lviv; Technische Universität DresdenThe results of modeling the properties of the semiconductor solid solution Lu1-xScxNiSb, x=0–0.10, which is a promising thermometric material for the manufacture of sensitive elements of thermocouples, are presented. Modeling of the electronic structure of Lu1-xScxNiSb was performed by the Korringa-Kohn-Rostoker (KKR) method in the approximation of coherent potential and local density and by the full-potential method of linearized plane waves (FLAPW). KKR simulations were performed using the AkaiKKR software package in the local density approximation for the exchange-correlation potential with parameterization Moruzzi, Janak, Williams. The Elk software package was used in the FLAPW calculations. To check the limits of the existence of the thermometric material Lu1-xScxNiSb by the KKR method, the change of the values of the period of the unit cell a(x) in the range x=0–0.10 was calculated. It is established that the substitution of Lu atoms in the crystallographic position 4a by Sc atoms is accompanied by a decrease in the values of the unit cell period a(x) Lu1-xScxNiSb. This behavior of a(x) Lu1-xScxNiSb is since the atomic radius Sc (rSc=0.164 nm) is smaller than that of Lu (rLu=0.173 nm). In this case, structural defects of neutral nature are generated in Lu1-xScxNiSb, because the atoms Lu (5d16s2) and Sc (3d14s2) are located in the same group of the Periodic Table of the Elements and contain the same number of d-electrons. To study the conditions for obtaining thermometric material Lu1-xScxNiSb, x=0–0.10, and to establish the energy feasibility of its formation in the form of a continuous solid solution, modeling of thermodynamic characteristics in the approximation of harmonic oscillations of atoms within the DFT density functional theory. The low values of the enthalpy of mixing ΔHmix(x) and the nature of the dependence behavior indicate the energy expediency of substitution in the crystallographic position 4a of Lu atoms for Sc atoms and the existence of a solid substitution solution for the studied samples Lu1-xScxNiSb, x=0–0.10. To understand the mechanisms of electrical conductivity of the thermometric material Lu1-xScxNiSb, x=0–0.10, various models of crystal and electronic structures of the basic semiconductor LuNiSb are considered. Assuming that the crystal structure of Lu1-xScxNiSb is ordered (crystallographic positions are occupied by atoms according to the MgAgAs structural type), the Elk software package was used to model the DOS electronic state density distribution for LuNiSb and Lu0.875Sc0.125NiSb. It is shown that in the LuNiSb compound the Fermi level lies in the middle of the band gap , and the bandwidth is =190.5 meV. DOS simulations for the ordered variant of the Lu0.875Sc0.125NiSb crystal structure show a redistribution of the density of DOS electronic states and an increase in the band gap . In this case, the Fermi level , as in the case of LuNiSb, lies in the middle of the band gap , and the generated structural defects are neutral. The DOS calculation for the disordered variant of the crystal structure of the LuNiSb compound was performed using a model that can be described by the formula Lu1+yNi1-2ySb. In this model, the Lu atoms partially move to the 4c position of the Ni atoms, and in this position, a vacancy (y) occurs simultaneously. Moreover, as many Lu atoms additionally move to the 4c position of Ni atoms, so many vacancies arise in this position. In this model of the crystal structure of the LuNiSb compound and the absence of vacancies (y=0), the calculation of the DOS electronic state density distribution indicates the presence of the band gap εg, and the Fermi level εF lies near the valence band εV. In the model of the structure of the LuNiSb compound at vacancy concentrations y=0.01, the DOS calculation also shows the presence of the band gap εg, and the Fermi level εF still lies near the valence band εV. Since Ni atoms make the greatest contribution to the formation of the conduction band εC, even at a concentration of y=0.02, the DOS calculation shows that the Fermi level εF now lies near the conduction band εC. This means that the main carriers of the electric current of the LuNiSb compound at y=0.02 are electrons, which does not correspond to the results of experimental studies. Based on the above model of the disordered crystal structure of the LuNiSb compound, the density distribution of DOS electronic states was calculated for the disordered variant of the crystal structure of the thermometric material Lu1-xScxNiSb, which is described by the formula Lu1-x+yScxNi1-2ySb. In this model of the Lu1-xScxNiSb crystal structure, the calculation of the DOS electronic state density distribution shows the presence of a band gap εg, in which small energy levels ("tail tails") are formed, which overlap with the zones of continuous energies. In this case, the Fermi level εF is localized at low energy levels, which makes it impossible to accurately determine the depth from the Fermi level εF. The proposed model is correct only for a small number of impurity Sc atoms since the partial occupation of the 4c position of Ni atoms by Lu atoms significantly deforms the structure with its subsequent decay. The results of experimental studies of the kinetic, energy, and magnetic properties of the thermometric material Lu1-xScxNiSb will show the degree of adequacy of the proposed model.Item Research of thermometric material Er1-xscxNiSb. I. Modelling of performances(Видавництво Львівської політехніки, 2021-02-23) Krayovskyy, Volodymyr; Pashkevych, Volodymyr; Horpenuk, Andriy; Romaka, Volodymyr; Stadnyk, Yuriy; Romaka, Lyubov; Horyn, Andriy; Romaka, Vitaliy; Lviv Polytechnic National University; Ivan Franko National University of Lviv; Leibniz Institute for Solid State ResearchAutomated The results of modeling performances of the semiconductor solid solution Er1–xScxNiSb are presented, which can be a promising thermometric material for the manufacture of sensitive elements of thermoelectric and electroresistive thermocouples. Fullprof Suite software was used to model the crystallographic characteristics of the Er1-xScxNiSb thermometric material. Modeling of the electronic structure of Er1–xScxNiSb was performed by Coring-Kon-Rostocker methods in the approximation of coherent potential and local density using the exchange-correlation potential Moruzzi-Janak-Williams and Linear Muffin-Tin Orbital in the framework of DFT density functional theory. The Brillouin zone was divided into 1000 k-points, which were used to model energetic performances by calculating DOS. The width of the energy window was 22 eV and was chosen to capture all semi-core states of p-elements. Full potential (FP) was used in the representation of the linear MT orbital in the representation of plane waves. The accuracy of calculating the position of the Fermi level was εF ± 6 meV. To verify the existence of a continuous solid solution, Er1–xScxNiSb substitution, the change in the values of the period of the unit cell a (x) was calculated within the framework of the DFT density functional theory in the range x = 0–1.0. It is presented that the calculated and experimentally obtained dependences of the period of the unit cell a(x) Er1–xScxNiSb are almost parallel, which confirms the correctness of the used tools and the obtained modeling results. To research the possibility of obtaining thermometric material Er1–xScxNiSb in the form of a continuous solid solution was performed modeling of thermodynamic calculations in the approximation of harmonic oscillations of atoms in the theory of DFT density functional for a hypothetical solid solution Er1–xScxNiSb, x = 0–1.0. It is shown that the change in the values of free energy ΔG(x) (Helmholtz potential) passes through the minimum at the concentration x≈0.1 for all temperatures of possible homogenizing annealing of the samples, indicating the solubility limit of Sc atoms in the structure of the ErNiSb compound. The presence of this minimum indicates that the substitution of Er atoms for Sc atoms in the ErNiSb compound is energetically advantageous only up to the concentration of impurity atoms Sc, x ≈ 0.1. At higher concentrations of Sc atoms, x > 0.10, stratification occurs (spinoidal phase decay). It is shown that modeling of the mixing entropy behavior S even at a hypothetical temperature T = 4000 K shows the absence of complete solubility of Sc atoms in Er1–xScxNiSb. To model the energetic and kinetic performances of the semiconductor thermometric material Er1–xScxNiSb, particularly the behavior of the Fermi level e F , bandgap width e g the distribution of the density of electronic states (DOS) and the behavior of its electrical resistance ρ(x, T) is calculated for an ordered variant of the structure in which the Er atoms in position 4a are replaced by Sc atoms. It is shown that the ErNiSb compound is a semiconductor of the electronic conductivity type, in which the Fermi level is located near the level of the conduction band e C . The modeling showed that at higher concentrations of Sc atoms, the number of generated acceptors exceeds the concentration of uncontrolled donors, and the concentration of free holes exceeds the concentration of electrons. Under these conditions, the Fermi level e F approaches, and then the level of the valence band Er1–xScxNiSb crosses: the dielectric-metal conductivity transition occurs. The experiment should change the sign of the thermo- EMF coefficient α(x, T) Er1–xScxNiSb from negative to positive, and the intersection of the Fermi level e F and the valence band changes the conductivity from activating to metallic: on the dependences ln(ρ(1/T)) the activation sites disappear, and the values of resistivity ρ increase with temperature.Item Investigation of thermometric material Ti1-xScxCoSb modeling of characteristics(Видавництво Львівської політехніки, 2020-02-24) Krayovskyy, Volodymyr; Rokomanyuk, Mariya; Romaka, Volodymyr; Horpenyuk, Andriy; Stadnyk, Yuriy; Romaka, Lyubov; Horyn, Andriy; Lviv Polytechnic National University; Ivan Franko National University of LvivThe second part of the complex research of Ti1-xScxCoSb thermometric material for the sensitive elements of thermoelectric and electro resistant thermal converters is presented. Simulation of thermodynamic, electrotechnical, energetic and structural characteristics of Ti1-xScxCoSb semiconductor thermometric material for various options of atoms placement is performed. It is determined that under the orderly variant of the crystal structure Ti1-xScxCoSb the characteristic simulation results do not correspond to the experimental research results of temperature and concentration dependences of the resistivity, thermoEMF coefficient of the Fermi εF level behavior character, etc. Thus, for the ordered structure of Ti1-xScxCoSb, the simulation showed that the substitution in the crystallographic position 4a of the TiCoSb compound of atoms Ti (3d24s2) at Sc (3d14s2) generates structural defects of the acceptor nature since the Sc atom has fewer 3 d-electrons. Adding to the TiCoSb the smallest in the experiment concentration of Sc atoms by replacing the Ti atoms radically changes the behavior of the resistivity ρ and the coefficient of thermo-EMF α Ti0.995Sc0.005CoSb. In the 80–350 K temperature range, the resistivity value ρ increases with temperature increasing, and the conductivity of Ti0.995Sc0.005CoSb is metallic. It means that the addition of the smallest in the experiment concentration of atoms Sc (x=0.005) which should generate acceptors changed the position of the Fermi level εF in a way that could only cause the appearance of donors in the semiconductor. Thus, if in TiCoSb the Fermi level εF laid in the restricted area, then the metallization of the conductivity Ti0.995Sc0.005CoSb indicates that it not only approached the conduction zone but also crossed its leakage level, and electrons remain the main carriers of electricity. This is indicated by the negative values of the thermo-EMF coefficient α Ti0.995Sc0.005CoSb, which is only possible if donors of unknown nature are generated. The metallization of the conductivity Ti0.995Sc0.005CoSb also does not match the results of the electronic structure simulation for the ordered structure variant. After all, the simulation demonstrates that at the smallest concentration of the Sc acceptor impurity, the Fermi level εF drifts from the conduction zone εC to the middle of the restricted zone εg. Therefore, in the high-temperature area of dependence ln(ρ(1/T)), there must be an activation area associated with the thermal emission of electrons from the Fermi level εF into the conduction zone εC, and the value of the electron activation energy ε1ρ should be greater than in the case of TiCoSb. To clarify the crystalline and electronic structure of the TiCoSb compound, electronic state density distribution (DOS) simulations were performed for various options of occupying crystallographic positions by atoms, as well as occupying by atoms of tetrahedral voids of structure that make up ~24 % of the unit cell volume. It is shown that structural defects of the donor and acceptor nature are present in the TiCoSb base compound as a result of the location in the tetrahedral voids of the structure of additional Co * atoms and the presence of vacancies in the crystallographic position of 4a of the Ti atoms. Introduction to TiCoSb compound of impurity Sc atoms by substitution at position 4a of Ti atoms generates structural defects of acceptor nature, and the ratio of Ti1-xScxCoSb in the concentrations of available defects of donor and acceptor nature determines the location of the Fermi level εF and mechanisms of conductivity. The obtained results allow us to predictably simulate and obtain thermometric materials Ti1- xScxCoSb for the sensitive elements of thermotransducers.Item Дослідження кінетичних характеристик чутливих елементів термоперетворювачів на основі Ti1-xMoxCoSb(Видавництво Львівської політехніки, 2019-02-28) Крайовський, В. Я.; Рокоманюк, М. В.; Ромака, В. А.; Ромака, Л. П.; Стадник, Ю. В.; Горинь, А. М.; Krayovskyy, Volodymyr; Rokomanyuk, Mariya; Romaka, Volodymyr; Romaka, Lyubov; Stadnyk, Yuriy; Horyn, Andriy; Національний університет “Львівська політехніка”; Львівський національний університет ім. І. Франка; Lviv Polytechnic National University; Ivan Franko National University of LvivВиконано математичне моделювання та експериментальні вимірювання кінетичних та енергетичних характеристик чутливих елементів термоперетворювачів на основі термометричного матеріалу Ti1-xMoxCoSb у діапазоні температур 80–400 К. Попередні дослідження електрофізичних, енергетичних та структурних властивостей термометричних матеріалів, отриманих легуванням напівгейслерової фази TiCoSb атомами Ni та V, відповідно, показали, що вони володіють стабільними та відтворюваними характеристиками у температурному діапазоні 4,2–1000 К. Встановлено, що результати моделювання термометричних характеристик чутливих елементів на основі TiCo1-xNixSb та Ti1-xVxCoSb не узгоджувалися з результатами експериментальних вимірювань, що унеможливило їхнє використання для виготовлення чутливих елементів термометрів опору та термоелектричних перетворювачів. Моделювання електронної структури термометричних матеріалів Ti1-xMoxCoSb методом функцій Гріна (метод Корінги–Кона–Ростокера (KKR)) у наближенні когерентного потенціалу (Coherent Potential Approximation) та локальної густини (Local Density Approximation) з використанням ліцензованого програмного забезпечення AkaiKKR та SPR-KKR для обмінно- кореляційного потенціалу з параметризацією Moruzzi-Janak-Williams показало, що заміщення атомів Ti на Mo генерує у кристалі структурні дефекти донорної природи (у Mo більше 3d-електронів, ніж у Ti), а в забороненій зоні поблизу зони провідності εС утворюється домішковий донорний рівень (зона) 2D e. Експериментальні вимірювання електрокінетичних характеристик термометричних матеріалів Ti1-xMoxCoSb встановили наявність високотемпературних активаційних ділянок на залежностях питомого опору ln(ρ(1/T)), що вказує на розташування рівня Фермі εF у забороненій зоні напівпровідника, а це можливо за умови генерування акцепторів, які захоплюють вільні електрони, зменшуючи їхню концентрацію, та гальмують рух рівня Фермі εF до рівня протікання зони провідності εС. Отже, легування сполуки TiCoSb домішкою Mo призводить до генерування у кристалі структурних дефектів акцепторної та донорної природи. Встановлено механізми електропровідності чутливих елементів термоперетворювачів.Item Properties of the hybrid glauconite/polyaniline composites synthesized in the aqueous citrate acid solutions(Publishing House of Lviv Polytechnic National University, 2016) Yatsyshyn, Mykhaylo; Makogon, Viktoriia; Reshetnyak, Oleksandr; Demchenko, Pavlo; Dumanchuk, Nataliya; Stadnyk, YuriyFor the first time the series of the composites of aniline and natural mineral glauconite with different ratio of components has been synthesized by oxidation of aniline by ammonium peroxydisulfate in 0.5 M citrate acid aqueous solutions in the presence of dispersion of mineral filler. X-ray phase analysis confirms the amorphous-crystalline structure of produced composites. Results of FTIR spectral analysis show that the samples contain PAn in the form of emeraldine salt and also indicate the presence of weak interfacial interaction between particles of glauconite and polyaniline macrochains in the result of the formation of hydrogen bonds. The results of thermogravimetric analysis of synthesized samples with different composition showed that thermal stability of composites samples increases under the higher glauconite content. It is determined that the thermodestruction of composites is a multistage process. The electric conductivity of composites produced samples with high content of polyaniline is on the level of pure polyaniline. The specific magnetization of synthesized composites in applied magnetic field increases to the value which is characteristic of the pure mineral under the increasing of glauconite content in the composite. Окисненням аніліну пероксодисульфатом амонію в 0,5 М водних розчинах цитратної кислоти за наявності природного мінералу глауконіту синтезовано ряд композитів із різним співвідношенням глауконіт/поліанілін. За допомогою рентгенофазового аналізу показано, що структура отриманих композитів є аморфно-кристалічною. Результати ІЧ-ФП спектрального аналізу зразків показали, що зразки містять ПАн у вигляді емеральдинової солі, а також вказують на наявність слабкої міжфазової взаємодії між частинками глауконіту і макроланцюгів поліаніліну внаслідок утворення водневих зв’язків. Порівняння результатів дериватографічних досліджень синтезованих зразків з різним складом показало, що зі збільшенням вмісту глауконіту підвищується термічна стійкість зразків композитів. Виявлено, що процес термодеструкції композитів є багатостадійним. Питома електропровідність отриманих композитів при високих вмістах поліаніліну знаходиться на рівні таких показників, як для чистого поліаніліну. Питома намагніченість отриманих композитів в прикладеному магнітному полі при збільшенні вмісту глауконіту в композитах зростає до значень близьких для чистого мінералу.Item Hybrid mineral-polymeric composite materials on the basis of the polyaniline and glauconite-silica(Publishing House of Lviv Polytechnic National University, 2013) Yatsyshyn, Mykhaylo; Reshetnyak, Oleksandr; Dumanchuk, Nataliya; Kulyk, Yuriy; Fartushok, Nataliya; Stadnyk, YuriyPolyaniline/glauconite-silica (PАn / Gl-Si) composite were obtained by one-step in situ polymerization of aniline in the presence of microdispersion of natural mineral glauconite-silica. The physicochemical properties (phase content, thermal stability, conductivity and magnetization) of the produced samples of composites with different ratio of components have been studied. It was shown that the polymeric component stipulates the conductivity for the synthesized composite samples, while the mineral particles stipulate their magnetic properties and higher thermal stability in comparison with individual polyaniline. Besides, it was determined that participation of the surface of glauconite-silica microparticles in the process of aniline polymerization leads to considerable increasing of ordering of the polymer in the composite. Мінерал-полімерні композити поліа нілін-кремнезем-глауконіт одержано in situ одностадійною полімеризацією аніліну в присутності мікродисперсних частинок природного мінералу кремнезем-глауконіт. Досліджено фізико-хімічні властивості (фазовий склад,термічну стійкість, електропровідність та намагнічуваність) отриманих зразків композиту різного складу. Встановлено, що полімерний компонент композиту визначає електричну провідність зразків синтезованого композиту,тоді як мінеральні частинки зумовлюють його магнітні властивості та вищу термічну стабільність порівняно з поліаніліном. Окрім того виявлено, що участь поверхні мікрочастинок глауконіт-кремнезему у процесі полімеризації аніліну призводить до суттєво зростання структурованості полімеру в композиті.