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BETA
Wójcik, Natalia A.
Alternative names
Publications (9 of 9) Show all publications
Wójcik, N. A., Kupracz, P., Barczyński, R. J. J., Jonson, B. & Ali, S. (2019). Ion conduction in beryllium-alumino-silicate glasses doped with sodium or sodium and lithium ions. Solid State Ionics, 341, Article ID 115055.
Open this publication in new window or tab >>Ion conduction in beryllium-alumino-silicate glasses doped with sodium or sodium and lithium ions
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2019 (English)In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 341, article id 115055Article in journal (Refereed) Published
Abstract [en]

Electrical properties of beryllium-alumino-silicate glasses containing sodium ions or sodium and lithium ions were studied with impedance spectroscopy technique over a frequency range from 10 mHz to 1 MHz and at temperature range from 213 to 473 K. The frequency- and temperature-dependent conductivity spectra of individual single alkali glasses were superimposed by means of the Summerfield scaling. Mixed-alkali glasses do not overlap into a single master curve. Glasses doped with sodium ions exhibit significantly higher values of D.C. conductivity and lower activation energy (~0.63 eV) than glasses doped with both sodium and lithium ions (~0.95 eV). The observed mixed-alkali effect can be described by the dynamic structure model (DSM). The conductivity pre-exponential factors and activation energy follow the Meyer-Neldel rule in both glass series. It was observed that the replacement of SiO2 by BeO in single cation glasses resulted in decrease in activation energy and pre-exponential factor σ0. In mixed cations glasses similar effect found for D.C. conduction process parameters was assigned to influence of both oxides BeO and Al2O3.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
D.C. conduction process Meyer-Neldel rule Anderson and Stuart model Beryllium-silicate glasses
National Category
Materials Engineering Ceramics Condensed Matter Physics
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-88752 (URN)10.1016/j.ssi.2019.115055 (DOI)
Funder
The Crafoord Foundation, 20160900ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 14-457Vinnova, 2015-04809
Available from: 2019-08-27 Created: 2019-08-27 Last updated: 2019-09-06Bibliographically approved
Wójcik, N. A., Ali, S., Möncke, D., Kamitsos, E., Segawa, H., Eriksson, M. & Jonson, B. (2019). The influence of Be addition on the structure and thermal properties of alkali-silicate glasses. Journal of Non-Crystalline Solids, 521, Article ID 119532.
Open this publication in new window or tab >>The influence of Be addition on the structure and thermal properties of alkali-silicate glasses
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2019 (English)In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 521, article id 119532Article in journal (Refereed) Published
Abstract [en]

Be-Na-(Li)-Si oxide glasses containing up to 15 mol% of BeO were prepared. Their structure was characterized by X-ray powder diffraction and Raman as well as infrared spectroscopic techniques, while their chemical compositions were examined by Inductively Coupled Plasma Optical Emission Spectrometry. All materials were found to be amorphous and contain Al contaminations from minor dissolution of the alumina crucibles. The results of Raman and IR spectroscopies showed that BeO addition to Na-(Li)-Si glass systems resulted in the formation of [BeO4/2]2− tetrahedra which are inserted into the silicate glass network, demonstrating the intermediate glass-forming role of BeO. In parallel, the effective destruction of Si-O-Si bridges was observed by vibrational spectroscopy. The glass transition temperature was studied by Differential Thermal Analysis and found to range from about 431 °C to 551 °C. A significant increase in Tg by 70 °C was found as SiO2 was substituted by up to 15 mol% BeO.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Beryllium-containing glasses Raman spectroscopy IR spectroscopy Alkali-silicate glasses Thermal properties
National Category
Ceramics Other Materials Engineering Materials Chemistry
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-87020 (URN)10.1016/j.jnoncrysol.2019.119532 (DOI)2-s2.0-85068177897 (Scopus ID)
Funder
The Crafoord Foundation, 20160900ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 14-457Vinnova, 2015-04809Knowledge Foundation, 68110029
Available from: 2019-07-29 Created: 2019-07-29 Last updated: 2019-09-26Bibliographically approved
Kupracz, P., Wojcik, N. A. & Barczynski, R. J. (2018). A method of determination of electrical conduction mechanisms in complex amorphous materials. Journal of Non-Crystalline Solids, 498, 223-227
Open this publication in new window or tab >>A method of determination of electrical conduction mechanisms in complex amorphous materials
2018 (English)In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 498, p. 223-227Article in journal (Refereed) Published
Abstract [en]

A novel approach to determine conduction mechanisms in complex amorphous materials was presented and tested on a real system. In the first step of the presented method, total electrical admittance of the material is analyzed in order to separate a couple of processes, each of which can be described by Jonscher's universal dielectric response. In the following step, a temperature dependence of dielectric response parameters of the processes is determined and compared with known models of conduction mechanisms in structural amorphous materials. Using this approach, a presence of two different conduction mechanisms describing electrical conductivity in a two-phase glass was described.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Impedance spectroscopy, Glass, Polaron hopping, Admittance, Electrical properties analysis
National Category
Materials Engineering
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-77367 (URN)10.1016/j.jnoncrysol.2018.06.028 (DOI)000440389500031 ()2-s2.0-85049332114 (Scopus ID)
Available from: 2018-08-28 Created: 2018-08-28 Last updated: 2019-08-29Bibliographically approved
Wójcik, N. A., Jonson, B., Barczynski, R. J., Kupracz, P., Woncke, D. & Ali, S. (2018). Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4. Solid State Ionics, 325, 157-162
Open this publication in new window or tab >>Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4
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2018 (English)In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 325, p. 157-162Article in journal (Refereed) Published
Abstract [en]

Sodium-calcium-phosphate glasses doped with SiO2 or Si3N4 having similar sodium ion concentrations were prepared by melt quenching. The conductivity was measured by impedance spectroscopy under nitrogen atmosphere in a wide frequency range (10 mHz-1 MHz) and wide temperature range (153-473 K). At 36.6 degrees C, DC conductivities of all glasses vary between 1.1 *10(-12) and 8.9 * 10(-12) S cm(-1) and have similar activation energies (between 0.87 and 0.91 eV), which are characteristic for an ionic conduction mechanism. The analysis of AC conductivities showed that the spectra are governed by one dynamic process - hopping of the mobile charge carriers - which may be described i.e., by the 'concept of mismatch and relaxation' or by the 'random barrier' model. The obtained results confirmed a higher influence of nitrogen incorporation on the various glass conductivity parameters than shown for silicon doping alone. However, the influence of fundamental structural changes on the glass conductivity is less relevant as is the overall sodium ion concentration, which remains the decisive factor for a high ion conduction.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Sodium-calcium-phosphate glasses, Oxynitride glass, Impedance spectroscopy
National Category
Materials Engineering
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-79009 (URN)10.1016/j.ssi.2018.08.011 (DOI)000449131900021 ()2-s2.0-85052467993 (Scopus ID)
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2019-08-29Bibliographically approved
Wojcik, N. A., Jonson, B., Möncke, D., Polies, D., Kamitsos, E. I., Ghassemali, E., . . . Ali, S. (2018). Influence of synthesis conditions on glass formation, structure and thermal properties in the Na2O-CaO-P2O5 system doped with Si3N4 and Mg. Journal of Non-Crystalline Solids, 494, 66-77
Open this publication in new window or tab >>Influence of synthesis conditions on glass formation, structure and thermal properties in the Na2O-CaO-P2O5 system doped with Si3N4 and Mg
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2018 (English)In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 494, p. 66-77Article in journal (Refereed) Published
Abstract [en]

Oxynitride phosphate glasses and glass-ceramics were prepared using new synthesis routes for phosphate glasses. Materials were melted from pre-prepared glass samples in the system Na-Ca-P-0 with addition of Mg and/or Si3N4 powders under different preparation conditions. The melting process was conducted at 1000-1500 degrees C either under air or nitrogen atmosphere to obtain materials with different nitrogen content. Their topography and structure were characterized by Confocal Microscopy, Scanning Electron Microscopy, X-ray powder diffraction and Raman and infrared spectroscopy techniques, while their chemical compositions were examined by Energy Dispersive X-ray spectroscopy (EDS). All materials prepared under nitrogen atmosphere were found to contain a relative low quantity of nitrogen and high amount of Nb leached from the crucible. The reaction with the Nb crucible was not previously observed for silicon-based oxynitride glasses. The synthesized materials form two groups: glasses and glass-ceramics. The first ones, were prepared under air and nitrogen atmospheres at temperatures up to 1400 degrees C, and were found to be amorphous and homogeneous. Raman and infrared spectroscopy measurements confirm the presence of amorphous phosphates in the synthesized materials. The samples of the second group were prepared at temperatures above 1400 degrees C and were found to be translucent and partially crystallized. They contain nanocrystallites of calcium and sodium phosphates including hydroxyapatite (HAp). The thermal properties of samples were studied by Differential Scanning Calorimetry (DSC). The obtained glass transition temperatures range from about 360 degrees C to 640 degrees C and exhibit high values for glass-ceramic materials. Stability is improved in the studied glass-ceramics because of the increased degree of network polymerization of the remaining glassy matrix. The approximate fragility index decreases two times for oxynitride materials compared to the primary glass. The synthesized new materials may be competitive to well-known bioactive phosphate glasses thanks to their improved stability by Mg, Si, N and Nb doping.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Sodium-calcium-phosphate glasses, Glass-ceramics, Oxynitride materials, Raman spectroscopy
National Category
Materials Engineering
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-76949 (URN)10.1016/j.jnoncrysol.2018.04.055 (DOI)000436885100009 ()2-s2.0-85046826853 (Scopus ID)
Available from: 2018-07-19 Created: 2018-07-19 Last updated: 2019-08-29Bibliographically approved
Wójcik, N. A., Jonson, B., Möncke, D., Barczyński, R., Kupracz, P., Kamitsos, E., . . . Ali, S. (2018). Influence of synthesis conditions on glass formation, structure, thermal and electrical properties in the Na2O-CaO-P2O5 system doped with Si3N4 and Mg. In: : . Paper presented at Seminar “Porous Glasses-Special Glasses”PGL’1, 12th -15th of Sep 2018, Szklarska Poreba, Poland.
Open this publication in new window or tab >>Influence of synthesis conditions on glass formation, structure, thermal and electrical properties in the Na2O-CaO-P2O5 system doped with Si3N4 and Mg
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2018 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Ceramics
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-82316 (URN)
Conference
Seminar “Porous Glasses-Special Glasses”PGL’1, 12th -15th of Sep 2018, Szklarska Poreba, Poland
Note

Ej belagd 190506

Available from: 2019-04-27 Created: 2019-04-27 Last updated: 2019-05-22Bibliographically approved
Möncke, D., Ali, S., Wójcik, N. A., Palles, D., Kamitsos, E. & Jonson, B. (2018). IR and Raman study of oxy-nitride glasses. In: Presented at Glass and the Meeting of Minds  (SGT18), Cambridge, UK (2nd -5th September 2018): . Paper presented at Glass and the Meeting of Minds (SGT18), Cambridge, UK (2nd -5th September 2018) (pp. 54).
Open this publication in new window or tab >>IR and Raman study of oxy-nitride glasses
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2018 (English)In: Presented at Glass and the Meeting of Minds  (SGT18), Cambridge, UK (2nd -5th September 2018), 2018, p. 54-Conference paper, Oral presentation with published abstract (Refereed)
National Category
Ceramics
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-82205 (URN)
Conference
Glass and the Meeting of Minds (SGT18), Cambridge, UK (2nd -5th September 2018)
Note

(invited Talk)

Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-05-08Bibliographically approved
Wojcik, N. A., Kupracz, P. & Barczynski, R. J. (2018). Nonlinear electrical properties of glass-ceramics nanocomposites containing ferroelectric nanocrystallites of Bi2VO5.5. Solid State Ionics, 317, 7-14
Open this publication in new window or tab >>Nonlinear electrical properties of glass-ceramics nanocomposites containing ferroelectric nanocrystallites of Bi2VO5.5
2018 (English)In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 317, p. 7-14Article in journal (Refereed) Published
Abstract [en]

Nonlinear A.C. impedance measurements were conducted in the 50BiV-50SrBAlO nanocomposite as a function of frequency, temperature and A.C. voltage. This material is ferroelectric below temperature of 730 K, and above 730 K is a good ion-conductor. For this nanocomposite a low A.C. voltage of 1 V-rms, is enough to observe high nonlinearities. The origin of these nonlinear effects depends on the temperature and frequency. In the high temperature and low frequency region, the nonlinearities are due to interfacial processes. In the low temperatures and higher frequencies, the nonlinearities may be also correlated with ion-transport processes: hopping and blocking in glass matrix and phase boundaries. The ferroelectric properties of the Bi2VO5.5 nanocrystallites are also possible origin of nonlinear effects. However, their contribution into nonlinearities is weaker than from the other observed processes. It is shown that a decrease of the Bi2VO5.5 crystallites size from micro- to nanometers and introduction of additional structural disorder into material significantly decrease the real part of the third order electric susceptibility coefficient but does not influence the ratio of the third harmonic to the base conductivity. It is suggested that the ferroelectric nanoregions are single-domain and the nonlinearities derived from domain walls probably are not observed.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Nonlinear conductivity, Nonlinear electric susceptibility, Glass-ceramics, Impedance spectroscopy
National Category
Materials Engineering
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-72687 (URN)10.1016/j.ssi.2017.12.035 (DOI)000428101100002 ()2-s2.0-85039979456 (Scopus ID)
Available from: 2018-04-13 Created: 2018-04-13 Last updated: 2019-08-29Bibliographically approved
Wójcik, N. A., Jonson, B., Möncke, D., Kamitsos, E., Segawa, H., Karczewski, J. & Ali, S. (1919). The effect of nitrogen on the structure and thermal properties of beryllium-containing Na-(Li)-Si-O-N glasses. Journal of Non-Crystalline Solids, 522, Article ID 119585.
Open this publication in new window or tab >>The effect of nitrogen on the structure and thermal properties of beryllium-containing Na-(Li)-Si-O-N glasses
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1919 (English)In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 522, article id 119585Article in journal (Refereed) Published
Abstract [en]

Two oxynitride glass series with the composition of 35Na2O-5BeO-(60-x)SiO2-xSi3N4 and 9Li2O- 27Na2O-5BeO-(59-x)SiO2-xSi3N4, were prepared. The glasses' topography and structure were studied by Scanning Electron Microscopy and Raman spectroscopy. The composition was analyzed by Inductively Coupled Plasma Optical Emission Spectrometer, SEM-EDS and nitrogen and oxygen elemental analyzer. Na-(Li)-Be-silicate glasses were found to contain up to approximately 3.4 (or 5.2 for EDS measurements) at.% of N, respectively. The samples were homogenous in their topography and compositions of their cross-sections.

The presence of three-fold coordinated nitrogen atoms in Na-Be-Si-O-N glasses results in higher degree of polymerization as was observed by Raman spectroscopy. The spectrum of analogous glasses with lithium did not show a significant decrease in Q2 units but exhibit the presence of Q4 units which also indicates a polymerization of the network. The incorporation of nitrogen in these glasses leads to the increase of the glass transition temperature and thermal stability.

Place, publisher, year, edition, pages
Elsevier, 1919
Keywords
Oxynitride glasses Beryllium-silicate glasses Raman spectroscopy Thermal properties
National Category
Materials Engineering Ceramics
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-88616 (URN)10.1016/j.jnoncrysol.2019.119585 (DOI)
Funder
The Crafoord Foundation, 20160900ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 2015-04809Knowledge Foundation, 68110029
Available from: 2019-08-26 Created: 2019-08-26 Last updated: 2019-09-04Bibliographically approved
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