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Ali, Sharafat, Associate Professor
Publications (10 of 55) 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, 1-7, 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, p. 1-7, 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)000495479700026 ()
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: 2019-11-29Bibliographically approved
Karlsson, S., Wondraczek, L., Ali, S. & Jonson, B. (2019). Kinetics of chemical strengthening and trends in effective diffusion coefficients. In: 25th International Congresson Glass (ICG 2019); ABSTRACT BOOK: June 9–14, 2019Boston, Massachusetts USA. Paper presented at 25th International Congress on Glass (ICG 2019), 9-14 June, 2019, Boston, USA (pp. 167-167). American Ceramic Society
Open this publication in new window or tab >>Kinetics of chemical strengthening and trends in effective diffusion coefficients
2019 (English)In: 25th International Congresson Glass (ICG 2019); ABSTRACT BOOK: June 9–14, 2019Boston, Massachusetts USA, American Ceramic Society, 2019, p. 167-167Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Alkali cation exchange has received significant attention with respect to introducing compressive stress in the glass surface, a process frequently called chemical strengthening. Besides mechanical properties may also other properties such as optical, electrical and chemical properties be modified using ion exchange of various monovalent ions. The mobility of monovalent ions varies and the relations of structural and effective diffusion coefficients may help to understand how to improve the ion exchange kinetics of soda lime silicates. We discuss the trends in the effective diffusion coefficients when exchanging Na+ for various monovalent cations (K+, Cu+, Ag+, Rb+ and Cs+) by their correlations to physico-chemical properties. The most significant correlations were found to be the bond dissociation energy and the electronic cation polarizability, indicating that electron localization and the rupture of bonds are of importance for the ion exchange rate.

Place, publisher, year, edition, pages
American Ceramic Society, 2019
National Category
Ceramics
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-89073 (URN)
Conference
25th International Congress on Glass (ICG 2019), 9-14 June, 2019, Boston, USA
Available from: 2019-09-11 Created: 2019-09-11 Last updated: 2019-09-18Bibliographically approved
Grund Bäck, L., Ali, S., Karlsson, S., Möncke, D., Kamitsos, E. & Jonson, B. (2019). Mixed alkali/alkaline earth‐silicate glasses: Physical properties and structure by vibrational spectroscopy. International Journal of Applied Glass Science, 10(3), 349-362
Open this publication in new window or tab >>Mixed alkali/alkaline earth‐silicate glasses: Physical properties and structure by vibrational spectroscopy
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2019 (English)In: International Journal of Applied Glass Science, ISSN 2041-1286, Vol. 10, no 3, p. 349-362Article in journal (Refereed) Published
Abstract [en]

In this article, we investigate the correlation of selected physical properties with structural changes in quaternary mixed modifier alkali/alkaline earth oxide silicate glass systems, focusing either on the mixed alkali effect [(20−x)Na2O–xK2O–10CaO–70SiO2 (x = 0, 5, 10, 15, 20)] or on the mixed alkaline earth effect [20Na2O–(10−y)CaO–yBaO–70SiO2 (y = 0, 5, 10)]. A maximum microhardness and packing density, as well as a minimum glass transition temperature were observed for mixed alkali glasses. The mixed alkaline earth glasses do not exhibit any clear extrema in any of the properties studied. The hardness and glass transition temperature decreases, while the density and molar volume increases with increasing BaO content. Raman spectroscopy showed an increase in the Q3 group compared to the Q2 and Q4 groups as the high field strength ions Na+ or Ca2+ are substituted by their low field strength analogs K+ or Ba2+. In the mixed alkali series, the high field strength ion Na+, seems to push the low field strength ion K+ into lower energy sites when present simultaneously, while such an effect is not apparent for the mixed alkaline earth glasses, where the far IR spectra of mixed glasses are equivalent to the weighted averages of the pure glasses.

Place, publisher, year, edition, pages
American Ceramic Society, 2019
Keywords
mixed modifier effect, silicate glass, glass transition temperature, hardness, Raman spectroscopy and IR spectroscopy
National Category
Ceramics
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-82150 (URN)10.1111/ijag.13101 (DOI)000470786300008 ()2-s2.0-85066607499 (Scopus ID)
Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-08-29Bibliographically approved
Ali, S. (2019). Novel thin films in the M-Si-O-N systems. In: Presented at the Fourth International Conference on Nanomaterials: Synthesis, Characterization and Applications (ICN 2019). 12-14 April 2019, Kerala, India: . Paper presented at Fourth International Conference on Nanomaterials: Synthesis, Characterization and Applications (ICN 2019). 12-14 April 2019, Kerala, India. (pp. 7-7).
Open this publication in new window or tab >>Novel thin films in the M-Si-O-N systems
2019 (English)In: Presented at the Fourth International Conference on Nanomaterials: Synthesis, Characterization and Applications (ICN 2019). 12-14 April 2019, Kerala, India, 2019, p. 7-7Conference paper, Oral presentation with published abstract (Refereed)
National Category
Nano Technology
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-82149 (URN)
Conference
Fourth International Conference on Nanomaterials: Synthesis, Characterization and Applications (ICN 2019). 12-14 April 2019, Kerala, India.
Note

(Invited Talk)

Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-05-07Bibliographically approved
Ali, S., Paul, B., Magnusson, R., Erik, E., Pallier, C., Jonson, B., . . . Birch, J. (2019). Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering. Surface & Coatings Technology, 372(25), 9-15
Open this publication in new window or tab >>Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering
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2019 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 372, no 25, p. 9-15Article in journal (Refereed) Published
Abstract [en]

In this work, amorphous thin films in Mg-Si-O-N system typically containing >15 at.% Mg and 35 at.% N were prepared in order to investigate especially the dependence of optical and mechanical properties on Mg composition. Reactive RF magnetron co-sputtering from magnesium and silicon targets were used for the deposition of Mg-Si-O-N thin films. Films were deposited on float glass, silica wafers and sapphire substrates in an Ar, N2 and O2 gas mixture. X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, spectroscopic ellipsometry, and nanoindentation were employed to characterize the composition, surface morphology, and properties of the films. The films consist of N and Mg contents up to 40 at.% and 28 at.%, respectively and have good adhesion to substrates and are chemically inert. The thickness and roughness of the films increased with increasing content of Mg. Both hardness (16–21 GPa) and reduced elastic modulus (120–176 GPa) are strongly correlated with the amount of Mg content. The refractive index up to 2.01 and extinction coefficient up to 0.18 were found to increase with Mg content. The optical band gap (3.1–4.3) decreases with increasing the Mg content. Thin film deposited at substrate temperature of 100 °C shows a lower value of hardness (10 GPa), refractive index (1.75), and higher values of reduced elastic modulus (124 GPa) as compared to the thin film deposited at 310 °C and 510 °C respectively, under identical synthesis parameters.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Mg-Si-O-N thin films Sputtering High magnesium content Hardness Modulus Refractive index Band gap
National Category
Ceramics Manufacturing, Surface and Joining Technology Nano Technology
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-82580 (URN)10.1016/j.surfcoat.2019.05.015 (DOI)000474676200002 ()2-s2.0-85065543888 (Scopus ID)
Funder
ÅForsk (Ångpanneföreningen's Foundation for Research and Development)Vinnova
Available from: 2019-05-16 Created: 2019-05-16 Last updated: 2019-08-29Bibliographically 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
Grund Bäck, L., Ali, S., Karlsson, S., Wondraczek, L. & Jonson, B. (2019). X-ray and UV-Vis-NIR absorption spectroscopy studies of the Cu(I) and Cu(II) coordination environments in mixed alkali-lime-silicate glasses. Journal of Non-Crystalline Solids: X, Article ID 100029.
Open this publication in new window or tab >>X-ray and UV-Vis-NIR absorption spectroscopy studies of the Cu(I) and Cu(II) coordination environments in mixed alkali-lime-silicate glasses
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2019 (English)In: Journal of Non-Crystalline Solids: X, ISSN 2590-1591, article id 100029Article in journal (Refereed) Published
Abstract [en]

The local structures of Cu(I) and Cu(II) in (20-x)Na2O-xK2O-10CaO-70SiO2 glasses with a copper content of 0.4 mol% have been investigated by Cu K-edge extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES). Complementary data for Cu(II) was derived using UV–Vis-NIR spectroscopy. Indication for mainly linear two-fold coordination of the Cu+ ion was found by both EXAFS and XANES, but other coordination between Cu+ and O2– cannot be excluded. The Cu(I)O bond lengths were found to be 1.79–1.83 ± 0.02 Å. EXAFS results showed that Cu(II) was mostly present in a Jahn-Teller distorted environment with oxygen, an octahedron with four shorter Cu(II)O bonds and two longer in axial position. The equatorial bond lengths were found to be 1.89–1.91 ± 0.02 Å and the axial 2.20–2.24 ± 0.02 Å with no effect of the Jahn-Teller distortion of the octahedron when the glass composition was altered.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Ceramics Materials Chemistry
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-46870 (URN)10.1016/j.nocx.2019.100029 (DOI)2-s2.0-85068376725 (Scopus ID)
Available from: 2015-10-26 Created: 2015-10-26 Last updated: 2019-09-02Bibliographically approved
Irshad, H. M., Hakeem, A. S., Ahmed, B. A., Ali, S., Ali, S., Ali, S., . . . Laoui, T. (2018). Effect of Ni content and Al2O3 particle size on the thermal and mechanical properties of Al2O3/Ni composites prepared by spark plasma sintering. International journal of refractory metals & hard materials, 76, 25-32
Open this publication in new window or tab >>Effect of Ni content and Al2O3 particle size on the thermal and mechanical properties of Al2O3/Ni composites prepared by spark plasma sintering
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2018 (English)In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 76, p. 25-32Article in journal (Refereed) Published
Abstract [en]

Alumina-nickel composites were prepared by carrying out spark plasma sintering (SPS) of nano-sized and micro-sized Al2O3particles with 15–45 wt% Ni powders. The powder materials were sintered at a temperature of1400 °C under a constant uniaxial pressure of 50 MPa. FESEM micrographs of the products showed uniformlydispersed nickel inclusions in both matrices at intergranular positions. Presence of Al2O3as the major phasealong with Ni as the minor phase was confirmed using XRD analysis. Thermal and mechanical properties of thenano- and micro-sized Al2O3/Ni composites were investigated. The thermal conductivity of nano-sized aluminacomposites was seen to increase with the increase in nickel content, however, an opposite trend was observed formicro-sized alumina-based composites. Moreover, thermal conductivities of all the composites decreased withincrease in temperature. The composites also showed high hardness and fracture toughness values of up to19.6 GPa and 4.71 MPa ∗ m1/2, respectively, and relative density values, between 79 and 99%, that decreasedwith increasing Ni content. Furthermore, the nano-sized Al2O3/Ni composites showed thermal and mechanicalproperties superior to those of the micro-sized Al2O3/Ni composite.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Alumina Nickel Composite Structural properties Thermo-mechanical properties Spark plasma sintering
National Category
Ceramics
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-75655 (URN)10.1016/j.ijrmhm.2018.05.010 (DOI)000441489200004 ()2-s2.0-85047607763 (Scopus ID)
Available from: 2018-06-12 Created: 2018-06-12 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
Ali, S. (2018). Hard and Transparent Thin Films. In: 4th Nanotechnology Congress and Expo  (GNCE-18), Dubai, UAE (16-18 Apr 2018): . Paper presented at 4th Nanotechnology Congress and Expo (GNCE-18), Dubai, UAE (16-18 Apr 2018) (pp. 14).
Open this publication in new window or tab >>Hard and Transparent Thin Films
2018 (English)In: 4th Nanotechnology Congress and Expo  (GNCE-18), Dubai, UAE (16-18 Apr 2018), 2018, p. 14-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-73022 (URN)
Conference
4th Nanotechnology Congress and Expo (GNCE-18), Dubai, UAE (16-18 Apr 2018)
Available from: 2018-04-18 Created: 2018-04-18 Last updated: 2018-10-22Bibliographically approved
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