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Ali, Sharafat, Associate Professor
Publications (10 of 51) Show all publications
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 ()
Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-07-15Bibliographically 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 ()
Funder
ÅForsk (Ångpanneföreningen's Foundation for Research and Development)Vinnova
Available from: 2019-05-16 Created: 2019-05-16 Last updated: 2019-07-25Bibliographically 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 ()
Available from: 2018-06-12 Created: 2018-06-12 Last updated: 2018-09-13Bibliographically 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 ()
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2019-05-22Bibliographically 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
Ali, S. (2018). High temeperature synthesis of nitrogen rich glasses in alkaline-earth silicon oxynitride systems. In: Presented at XVI International IUPAC Conference on High Temperature Materials Chemistry, Ekaterinaburg, Russia: . Paper presented at XVI International IUPAC Conference on High Temperature Materials Chemistry, Ekaterinaburg, Russia (2nd -6th July 2018) (pp. 24).
Open this publication in new window or tab >>High temeperature synthesis of nitrogen rich glasses in alkaline-earth silicon oxynitride systems
2018 (English)In: Presented at XVI International IUPAC Conference on High Temperature Materials Chemistry, Ekaterinaburg, Russia, 2018, p. 24-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-82204 (URN)
Conference
XVI International IUPAC Conference on High Temperature Materials Chemistry, Ekaterinaburg, Russia (2nd -6th July 2018)
Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-05-07Bibliographically 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 ()
Available from: 2018-07-19 Created: 2018-07-19 Last updated: 2018-07-19Bibliographically 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
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