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  • 1.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Glass surface modification by aerosol technique2016Other (Refereed)
    Abstract [en]

    Glass has been a key material for many important advnces in cilivilization.  Currently there is much scientific and technological interest to obtained flat/float glass surface that has extremely highly resistant to abrasion, anti-fingerprint, surface contamination and optical dimming. The aim of current project is to develop new routes to modify the glass surface in order to increase functionality and enhance performance in various existing and future areas of application. This will be achieved by modifying the glass surface by incorporating nitrogen to the flat/float glass surface by deposition of thin coatings of AlN, Si3N4 and TiN. This will be achieved by gas to particle conversion by physiochemical routs. Thin films of elemental nitrides have not been reported previously by aerosol technique and we anticipate that these can be used to enhance the mechanical, optical and chemical properties of flat/float glass surface. Techniques used for structural and physical characterization include, SEM, TEM, AFM, Raman, thermal analysis, mechanical and optical measurements. Areas of applications of these modified surfaces include automotive, architectural, laser optics, camera lenses, optical filters and display technologies.

  • 2.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hard and Transparent Thin Films2018In: 4th Nanotechnology Congress and Expo  (GNCE-18), Dubai, UAE (16-18 Apr 2018), 2018, p. 14-Conference paper (Refereed)
  • 3.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    High temeperature synthesis of nitrogen rich glasses in alkaline-earth silicon oxynitride systems2018In: Presented at XVI International IUPAC Conference on High Temperature Materials Chemistry, Ekaterinaburg, Russia, 2018, p. 24-Conference paper (Refereed)
  • 4.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    New Oxynitride Glasses and Thin Films2017In: 15th International Symposium on Advanced Materials (ISAM), Islamabad, Pakistan, 16-20 Oct 2017, 2017Conference paper (Refereed)
  • 5.
    Ali, Sharafat
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Nitrogen in Materials2010Conference paper (Refereed)
  • 6.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Nitrogen rich Glasses and Glass Surfaces for High-tech and Specialty Applications2017Report (Refereed)
    Abstract [en]

    The aim of this project is to produce more chemical and mechanically durable glasses and glass surfaces having high thermal, mechanical and optical properties. The development of new materials is fundamental for the technological progress; their preparation and characterization lead to breakthrough applications as well as progress in our understanding of basic solid state materials properties. Glasses play an important role in our society and are expected to do so even more in the future. In the current proposed project we would like to extend the M-Si-O-N  ( M= Ca and Sr) system to T-Si-O-N (T= Transition metals e.g. Ti, Zr, Y, Mn etc) and Ln-Si-O-N ( Ln = Lanthanoids e.g. La, Ce, Pr, Eu, Gd, etc) systems. Applications of these nitrogen rich glasses include, as potential materials for use in more light-weight applications in modern communications equipment, in biomedical devices and where reductions in energy usage are critical. Furthermore, these glass materials can be used as a passive coatings on electronic substrates using their higher dielectric constants and elastic moduli to best advantage; special windows where their higher elastic moduli would allow them to remain stiff in thinner sections, thus allowing weight and energy savings; hard disk drives, again making use of higher modulus and lower densities to achieve higher rotation speeds; new bioactive oxynitride glasses and glass-ceramics with better load-bearing properties.

  • 7.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Novel thin films in the M-Si-O-N systems2019In: 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 (Refereed)
  • 8.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Primary Challenges in the Development of Nitrogen Rich Oxynitride Glasses2018Conference paper (Refereed)
  • 9.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Berastegui, Pedro
    Stockholm University.
    Esmaeilzadeh, Saeid
    Stockholm University.
    Eriksson, Lars
    Stockholm University.
    Jekabs, Grins
    Stockholm University.
    A cubic calcium oxynitrido-silicate, Ca2.89Si2N1.76O4.242011In: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 67, article id i66Article in journal (Refereed)
    Abstract [en]

    The title compound, tricalcium oxynitride silicate, withcomposition Ca3-xSi2N2-2xO4+2x (x ’ 0.12), is a perovskiterelatedcalcium oxynitrido silicate containing isolated oxynitridosilicate 12-rings. The N atoms are statistically disorderedwith O atoms (occupancy ratio N:O = 0.88:0.12) and occupythe bridging positions in the 12 ring oxynitrido silicate anion,while the remaining O atoms are located at the terminalpositions of the Si(O,N)4 tetrahedra. The majority of the Ca2+cations fill the channels along [100] in the packing of the 12-ring anions. The rest of these cations are located at severalpositions, with partial occupancy, in channels along the bodydiagonals.

  • 10.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Bogdonoff, Toni
    Jönköping University.
    Seifeddine, Salem
    Jönköping University.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hardness, elastic modulus and refractive index of oxynitride glasses prepared from woody biofuel ashes2017In: Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B, ISSN 1753-3562, Vol. 58, no 6, p. 231-236Article in journal (Refereed)
    Abstract [en]

    This paper reports the hardness, elastic modulus and refractive index values of the oxynitride glasses prepared from woody biofuel ashes. The glasses were prepared in nitrogen atmosphere at 1350–1500°C with addition of Ca metal as a precursor to the extra addition of this modifier. The glasses were homogenous, but appeared translucent grey to black. They contained up to 23 eq% of Ca and 5 eq% of N. The glass densities vary slightly between 2.76 to 2.92 g/cm3. The molar volume and compactness values vary between 8.01 cm3/mol to 8.31 cm3/mol and 0.446 to 0.462 respectively. Mechanical properties like hardness and reduced elastic modulus show values, up to 10 and 105 GPa, respectively. These properties are strongly correlated with the amount of N in the glass. The refractive index (1.54–1.75) increases with increasing N and Ca contents.

  • 11.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Grins, J.
    Stockholm University.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Raman spectra of Ca-Si-O-N glasses2012Conference paper (Refereed)
  • 12.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Compositional effects on the properties of high nitrogen content alkaline-earth silicon oxynitride glasses, AE = Mg, Ca, Sr, Ba2011In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 31, no 4, p. 611-618Article in journal (Refereed)
    Abstract [en]

    A series of alkaline-earth element containing high nitrogen content oxynitride glasses (AESiON), with AE = Mg, Ca, Sr, Ba, were prepared in order to investigate the compositional effects on the physical properties of the alkaline-earth element. The physical properties were found to change linearly with the concentration of AE elements. The density of the glasses increases substantially with an increase in the AE atomic mass and slightly with an increase in nitrogen ratio. Ba containing glasses shows the value of density 4.16 g/cm3. Glass transition temperatures are found to be higher for Mg glasses, ca. 1020 °C, in comparison with Ba glasses, ca. 895 °C. The hardness of Mg containing glasses shows high values, up to 12.2 GPa and decreases for Ca, Sr and Ba containing glasses. Ba, containing glasses shows high values of refractive index in comparison with the Sr, Ca and Mg containing glasses.

  • 13.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Difficulties associated with the formation of oxynitride glasses2014Conference paper (Refereed)
  • 14.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Effect of compactness on oxynitride glasses properties2013Conference paper (Refereed)
  • 15.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Formation and properties of nitrogen rich Ca-Si- (Al)-O-N glasses and Ceramics2014In: Conference proceeding 2014 Spring World Congress on Engineering and Technology, Shanghai, China (April 2014)., 2014, p. 59-59Conference paper (Refereed)
  • 16.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Formation of oxynitride glasses from fly ashes2010In: Abstracts - 10th ESG conference together with 84th annual meeting of the DGG : Glass Trend Seminar "Glass Furnaces and Refractory Materials": Plansee Session "Refractory Methals for the Glass Industry ; Magdeburg, Germany, 30 May - 2 June 2010, 2010, p. 89-Conference paper (Refereed)
  • 17.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Glasses in the Ba–Si–O–N System2011In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 94, no 9, p. 2912-2917Article in journal (Refereed)
    Abstract [en]

    The preparation and properties of Ba–Si–O–N glasses arereported. These oxynitride glasses were prepared by meltingmixtures of BaH2, SiO2, and Si3N4 powders in a nitrogenatmosphere at 1550°–1700°C. The glasses were characterized by X-ray powder diffraction, differential thermal analysis, and scanning electron microscopy. Final glass compositions were calculated from analyses obtained by energy dispersive X-ray(EDX) spectroscopy and combustion analysis, for cation and anion compositions, respectively. The glasses were found to behomogenous, translucent gray to opaque black, and consists of N contents of up to 42 equiv% and Ba contents of up to 36 equiv%. Determined glass densities varied between 3.27 and 4.18 g/cm3, and calculated molar volumes varied between1 0.28 and 11.11 cm3/mol. Both density and molar volume increase with Ba content. Glass compactness (0.45–0.49), glasstransition temperature (786°–905°C), and microhardness (7.93–9.56 GPa) were found to increase linearly with N content. There fractive index increased from 1.66 to 1.91 and was found tobe strongly correlated with the amounts of Ba and N.

  • 18.
    Ali, Sharafat
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Jonson, Bo
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Nitrogen rich Ca/Sr-Si-O-N glasses crystallization2009Conference paper (Refereed)
  • 19.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Oxidation behavior of nitrogen rich AE-Si-O-N glasses (AE = Ca, Sr, Ba)2011In: Journal of the Australian Ceramic Society, ISSN 0004-881X, Vol. 47, no 2, p. 8-12Article in journal (Refereed)
    Abstract [en]

    AE-based silicon oxynitride glasses (AE = Ca, Sr, Ba) with high nitrogen content have been synthesized using AE hydrides as primary precursors. The oxidation behavior of AE-Si-O-N glasses in ordinary atmosphere at different temperature has been investigated. These glasses react with air oxygen when heated just above the glass transition temperatures. The oxidation starts with bubble formation on the surface and continued oxidation leads to formation of a white layer on the surface. The oxidation of AE-Si-O-N glasses involves concurrently ongoing inward diffusion of oxygen and outward diffusion of AE elements and nitrogen, resulting in compositional gradient. EDX analysis showed substantial enrichment in AE content at the surfaces of the oxidized layer.

  • 20.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Oxynitride glasses2012Conference paper (Refereed)
  • 21.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Preparation and properties of high nitrogen content mixed alkaline-earth oxynitride glasses2011Conference paper (Refereed)
  • 22.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Preparation of oxynitride glasses from woody biofuel ashes.2010In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 356, no 50-51, p. 2774-2777Article in journal (Refereed)
    Abstract [en]

    Oxynitride glasses have been prepared by melting woody biofuel ash from a power plant in south Sweden with addition of calcium metal as an extra modifier in a nitrogen atmosphere at 1350–1500 °C. The glasses were characterized by X-ray powder diffraction, differential thermal analysis and scanning electron microscopy. Cation and anion glass compositions were determined by energy dispersive X-ray analysis and combustion analysis, respectively. The glasses were found to be homogenous, translucent gray to black, and to contain up to 23 e/o of calcium and 5 e/o of nitrogen. The glass formation depends on the ratio of calcium metal introduction to the ash precursors. A strong exothermic reaction was observed at 650–850 °C, leading to the formation of amorphous and crystalline oxynitride phases that melt at high temperatures upon further heating. The glass densities vary between 2.76 g/cm3 and 2.92 g/cm3. The glass transition temperature was found to vary from 670 °C to 749 °C and increase linearly with the nitrogen content.

  • 23.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Properties of nitrogen rich mixed La-Pr silicon oxynitride glasses2014Conference paper (Refereed)
  • 24.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Thermal properties of calcium silicon oxynitride glasses2015Conference paper (Refereed)
    Abstract [en]

    Oxynitride glasses are a branch of high performance glasses, obtained by incorporation of nitrogen atoms into oxide glass network. [1-3]Oxynitride glasses have superior mechanical, rheological and optical properties as compared to their oxide glass counter partner [2-5]. Properties of these glasses can be tailored by changes in nitrogen content and additions of various alkaline-earth and or rare-earth elements. Ca- Si-O-N glasses containing high amount of nitrogen and modifiers have been prepared by melting the mixture of CaH2, SiO2 and Si3N4 powder in nitrogen atmosphere. The glasses were characterized by X-ray powder diffraction, differential thermal analysis and scanning electron microscopy. The obtained glasses were found to be homogenous, and having colour opaque black[3]. These glasses show high values of glass transition temperature (1050°C), and crystallization temperatures (1150°C) measured by differential thermal analysis.  Generally the Ca-Si-O-N glasses thermal properties evolve approximately linearly with the nitrogen content. The viscosity increases significantly with the nitrogen content and reaches viscosity values close to reported values for rare-earth silica oxynitride glasses. The apparent viscosity activation energies are very high, ranging from 855 to 2170 kJ/mole. These nitrogen rich glasses can accordingly be classified as being both very refractory and very fragile.

     

  • 25.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    J. Pomeroy, Michael
    University of Limerick, Ireland.
    Stuart, Hampshire
    University of Limerick, Ireland.
    Issues associated with the development of transparent oxynitride glasses2015In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 41, no 3, p. 3345-3354Article in journal (Refereed)
    Abstract [en]

    Oxynitride glasses and glass ceramics are increasingly recognized as potential materials in specialist applications in modern industrial sectors. Oxynitride glasses have superior mechanical, rheological and optical properties to their oxide glass counterparts. Properties of these glasses can be tailored by changes in nitrogen content and additions of various alkaline-earth and or rare-earth elements. In contrast to oxide glasses, oxynitride glasses are difficult to prepare which adds to production costs. Furthermore, they contain impurities in the form of elemental silicon and silicides, have poor oxidation resistance in air above their glass transition temperatures and have poor transparency in the visible region. This article reviews the above issues in relation to the potential applications of these glasses.

  • 26.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mauro, Jan
    Penn State University, USA.
    Properties of nitrogen rich Mg-Ca-Si-O-N glasses2017In: 12th  Pacific Rim Conference on Cermics and Glass Technology including Glass & Optical Materials Meeting, Hawii, USA 21-27 May 2017, 2017, p. 180-180, article id GOMD-S1-061-2017Conference paper (Refereed)
    Abstract [en]

    Mg-Ca-Si-O-N glasses containing high amount of nitrogen have been prepared by melting the mixture of Mg metal, Ca metal, SiO2 and Si3N4 powders in nitrogen atmosphere using a radio frequency furnace. Chemical composition, surface morphology, glass transition temperature, hardness, reduced elastic modulus and refractive index of the glasses were investigated using X-ray (EDX) point analysis, scanning electron microscopy, differential thermal analysis, nanoindentation, and spectroscopic ellipsometry. Mg was substituted for Ca in these glasses. The obtained glasses were found to be homogenous, and most of them were not transparent in the visible region. These glasses show high values of glass transition temperature (1020°C), and crystallization temperatures (1150°C). The hardness and reduced elastic modulus increases upon substitution by Mg, up to 13 GPa and 150 GPa respectively. The refractive index of the glasses was found to decrease upon increasing substitution by Mg.

  • 27.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonsson, Bo
    Eklund, Per
    Birch, Jens
    Modification of float glass surfaces by novel oxy-nitride thin films2015Report (Refereed)
    Abstract [en]

    Glass is indispensable and innovative material that has plenty of applications. It is an essential component of numerous products that we use every day, most often without noticing it. Glass is widely used in a variety of applications e.g. housing and buildings, automotive and transport, containers, drinking vessels, displays, insulation and optical fibers due to its universal forming ability, transparency, chemical durability, form stability, hardness relatively low price and possibility of recycling. Flat glass is a wide market of the glass industry and generally ninety percent of all flat glass produced worldwide is manufactured using the float forming process. There is a large market strive for thinner and stronger glass in order to reduce costs, save energy, and to find new applications.

    This study comprises the modification of flat/float glass surface by novel oxynitride thin films in the Mg-Si-O-N and Ca-Si-O-N systems prepared by RF magnetron sputtering technique. The aim of this work is to develop a novel process in order to improve the mechanical and optical properties of flat/float glass by deposition of external materials e.g. alkaline earth metals and nitrogen to the surface in a process with the obvious potential to be automatic in industrial processes. Both mechanical and optical properties of the glass surface have been improved by the deposition of thin films. The float glass surface modified with Mg-Si-O-N have high value of hardness of 20 GPa, elastic modulus of 175 GPa and refractive index value of 1.96 compare to the float glass having hardness of 7 GPa, elastic modulus of 72 GPa and refractive index of 1.50.  The method presented here is anticipated to be used in production in the future and would make it possible to produce larger quantities of strong flat glass for smartphone, tablet covers and display technology to a considerably lower cost.

  • 28.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Corning Inc, USA.
    Paul, Biplab
    Linköping University.
    Magnusson, Roger
    Linköping University.
    Broitman, Esteban
    Linköping University.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Eklund, Per
    Linköping University.
    Birch, Jens
    Linköping University.
    Synthesis and characterization of the mechanical and optical properties of Ca-Si-O-N thin films deposited by RF magnetron sputtering2017In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 315, p. 88-94Article in journal (Refereed)
    Abstract [en]

    Ca-Si-O-N thin films were deposited on commercial soda-lime silicate float glass, silica wafers and sapphire substrates by RF magnetron co-sputtering from Ca and Si targets in an Ar/N-2/O-2 gas mixture. Chemical composition, surface morphology, hardness, reduced elastic modulus and optical properties of the films were investigated using X-ray photoelectron spectroscopy, scanning electron microscopy, nanoindentation, and spectroscopic ellipsometry. It was found that the composition of the films can be controlled by the Ca target power, predominantly, and by the reactive gas flow. Thin films in the Ca-Si-O-N system are composed of N and Ca contents up to 31 eq. % and 60 eq. %, respectively. The films thickness ranges from 600 to 3000 nm and increases with increasing Ca target power. The films surface roughness varied between 2 and 12 nm, and approximately decreases with increasing power of Ca target. The hardness (4-12 GPa) and reduced elastic modulus (65-145 GPa) of the films increase and decrease with the N and Ca contents respectively. The refractive index (1.56-1.82) is primarily dictated by the N content. The properties are compared with findings for bulk glasses in the Ca-Si-(Al)-O-N systems, and it is concluded that Ca-Si-O-N thin films have higher values of hardness, elastic modulus and refractive index than bulk glasses of similar composition. (C) 2017 Elsevier B.V. All rights reserved.

  • 29.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Paul, Biplab
    Linköping University, Sweden.
    Magnusson, Roger
    Linköping University, Sweden.
    Erik, Ekström
    Linköping University, Sweden.
    Pallier, Camille
    Linköping University, Sweden.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Eklund, Per
    Linköping University, Sweden.
    Birch, Jens
    Linköping University, Sweden.
    Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering2019In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 372, no 25, p. 9-15Article in journal (Refereed)
    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.

  • 30.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Paul, Biplab
    Linköping University.
    Magnusson, Roger
    Linköping University.
    Greczynski, Grzegorz
    Linköping University.
    Broitman, Esteban
    Linköping University.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Eklund, Per
    Linköping University.
    Birch, Jens
    Linköping University.
    Novel transparent Mg-Si-O-N thin films with high hardness and refractive index2016In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 131, p. 1-4Article in journal (Refereed)
    Abstract [en]

    There is an increasing demand for glass materials with better mechanical and optical properties for display and electronic applications. This paper describes the deposition of novel thin films of Mg-Si-O-N onto float glass substrates. Amorphous thin films in the Mg-Si-O-N system with high nitrogen and magnesium contents were deposited by reactive RF magnetron co-sputtering from Mg and Si targets in Ar/N2/O2 gas mixtures. The thin films studied span an unprecedented range of compositions up to 45 at% Mg and 80 at% N out of cations and anions respectively. Thin films in the Mg-Si-O-N system were found to be homogeneous and transparent in the visible region. Mechanical properties like hardness (H) and reduced elastic modulus (Er) show high values, up to 21 GPa and 166 GPa respectively. The refractive index (1.87-2.00) increases with increasing magnesium and nitrogen contents.

  • 31.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Paul, Biplab
    Linköping University, Sweden.
    Magnusson, Roger
    Linköping University, Sweden.
    Greczynski, Grzegorz
    Linköping University, Sweden.
    Broitman, Esteban
    Linköping University, Sweden.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Eklund, Per
    Linköping University, Sweden.
    Birch, Jens
    Linköping University, Sweden.
    Thin films in M-Si-O-N thin systems2017In: 44th International Conference on Metallurgical Coating and Thin Films (ICMCTF), San Diego, CA, USA, 24-28 Apr 2017, 2017Conference paper (Refereed)
  • 32.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Paul, Biplab
    Magnusson, Roger
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Eklund, Per
    Birch, Jens
    Study of SiN, SiON and Mg-Si-O-N thin films by spec-troscopic elipsometry2016In: Optics and photonics conference, 2-3 November, 2016, Linköping, Sweden, 2016Conference paper (Refereed)
  • 33.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Melting Characteristics and Morphology of Bottom Ash and Filter Ash of the Circulating Fluidized Bed Boiler2013In: 21st European Biomass Conference and Exhibition, Copenhagen, Danmark, 3rd-7th June, 2013, ETA-Florence Renewable Energies , 2013, p. 1189-1191Conference paper (Refereed)
    Abstract [en]

    The aim of this work was to investigate the melting characteristics and morphology of filter ash and bottom ash with and without 7% of peat addition to the fuel of the circulating fluidized bed boiler. The samples were characterized by simultaneous thermal analysis (STA) and scanning electron microscope (SEM). The STA results indicate that the filter ash melts at 1140oC with 10 wt% of the mass loss and Bottom ash partially melts at 1170oC with below 2 wt% of the mass loss. The low melting point of the filter ash is due to the high concentration of the alkali metals in the filter ash. Similar trends were observed in the case of fly ash and bottom ash with peat admixture to the fuel. Furthermore the elementary analysis via scanning electron microscopy, coupled with energy-dispersive X-ray analysis showed that 7% of peat addition to the fuel does not significantly effect on the ash composition.

  • 34.
    Birch, Jens
    et al.
    Linköping University.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Eklund, Per
    Linköping University.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Synthesis and properties of vitreous thin films based on M2+ and M3+ modified silicon oxynitrides.2017In: ICG Annual Meeting & 32nd Sisecam Glass Symposium, Istanbul, Turkey (22-25 October  2017), 2017Conference paper (Refereed)
  • 35.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Aerosolkatalysatorer för industriell gasrening2016Report (Refereed)
    Abstract [en]

    Aerosol catalysts – small particles (with aerodynamic diameter up to 100 m) of catalytically active material suspended in gas – were examined for the intended use of NOx reduction with ammonia (SCR) in smaller industrial plants and boilers as an alternative to SNCR. The aerosol particles are intended to be injected into the flue gas at high temperature, together with ammonia/urea, and then separated on a particulate filter (bag‐type filter) at low temperature. The NOx reduction can occur during the pneumatic transport in the boiler or/and on the catalytically active filter cake. The catalysts must have sufficiently high activity in order to keep down their consumption, they must be cheap enough to be used as a consumable item, and must be harmless to humans and the environment. Two materials were developed during the work as possible candidates: natural zeolites and a FeSO4/activated carbon‐based catalyst. Cost estimates, for a hypothetical 1 MWth plant, shows that a NOx reduction close to 50% economically justify the introduction of SNCR for small plants (<25 GWh, NOx reductions levels between 30‐50% and 2 in stoichiometric ratio), both for the use of urea and liquid anhydrous ammonia with the percent NOx fee of 50 SEK/kg. The result is modest, at best 15‐20% cost reduction compared to no action. Raised tariffs to 60 SEK/kg NOx will improved the situation, but the results are still modest. When the aerosol catalysts was used in the cost estimate, and an assumed NOx reduction degree of 85% was supposed to be reached, good results were obtained at low catalyst costs (0.5‐2 SEK/kg). However the plant can handle at most a cost of 4 SEK/kg. Estimated cost for the aerosol catalyst is in the range of 10 SEK/kg. In order to be economically attractive, the catalyst should be recycled, thereby lowering the cost of catalyst consumption.

  • 36.
    Grund Bäck, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Karlsson, Stefan
    Glafo, the Glass Research Institute.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Physical properties and Raman Spectroscopy of mixed alkali/alkaline earth silicate glassesManuscript (preprint) (Other academic)
  • 37.
    Grund Bäck, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. RISE, Sweden.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Karlsson, Stefan
    RISE, Sweden.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Hellenic Research Foundation, Greece.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Greece.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mixed alkali/alkaline earth‐silicate glasses: Physical properties and structure by vibrational spectroscopy2019In: International Journal of Applied Glass Science, ISSN 2041-1286, Vol. 10, no 3, p. 349-362Article in journal (Refereed)
    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.

  • 38.
    Grund Bäck, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. RISE Research Institutes of Sweden, Sweden.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Karlsson, Stefan
    RISE Research Institutes of Sweden, Sweden;Friedrich Schiller University of Jena, Germany.
    Wondraczek, Lothar
    Friedrich Schiller University of Jena, Germany.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    X-ray and UV-Vis-NIR absorption spectroscopy studies of the Cu(I) and Cu(II) coordination environments in mixed alkali-lime-silicate glasses2019In: Journal of Non-Crystalline Solids: X, ISSN 2590-1591, article id 100029Article in journal (Refereed)
    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.

  • 39.
    Grund, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Optical and Physical Properties of CuO-doped mixed alkali: alkaline earth silica glasses2014Conference paper (Refereed)
  • 40. Gueguen, Yann
    et al.
    Ali, Sharafat
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Grins, Jekabs
    Rouxel, Tanguy
    Viscosity of high-nitrogen content Ca–Si–O–N glasses2010In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 30, no 16, p. 3455-3458Article in journal (Other academic)
    Abstract [en]

    The viscosity of three high-nitrogen content Ca–Si–O–N glasses, with 30–58 e/o N and 36–39 e/o Ca, was determined by micro-indentation. The measurements were made using an automated set-up, designed and built in-house, capable of measurements up to 1200 °C with applied loads of 0.01–15 N. The viscosity increases significantly with the nitrogen content and reaches viscosity values close to reported values for rare-earth silica oxynitride glasses. The glass transition temperatures range between 878 and 995 °C and are in very good agreement with values measured by differential thermal analysis. The apparent viscosity activation energies are very high, ranging from 855 to 2170 kJ/mol. The glasses can accordingly be classified as being both very refractory and very fragile. Implications of the viscosity values and mechanical properties of the glasses for their structures are discussed.

  • 41.
    Hakeem, Abbas Saeed
    et al.
    King Fahd University of Petroleum & Minerals (KFUPM).
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Preparation and properties of mixed La–Pr silicate oxynitride glasses2013In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 368, p. 93-97Article in journal (Refereed)
    Abstract [en]

    The preparation and properties of mixed lanthanide (La, Pr) silicate oxynitride glasses are reported. These oxynitride glasses were prepared by melting mixtures of La, Pr, SiO2 and Si3N4 powders in a nitrogen atmosphere at 1750 °C. The glasses were characterized by X-ray powder diffraction, differential thermal analysis, scanning and transmission electron microscopy. Glass compositions were calculated from the analyses obtained by energy dispersive X-ray (EDX) spectroscopy and combustion analysis, for cation and anion compositions, respectively. The glasses were found to be homogenous, optically opaque black, and to contain contents up to 66 e/o of N and up to 48 e/o of La–Pr. The physical properties were found to vary linearly with the degree of substitution of La by the Pr. Determined glass density increases substantially upon the substitution of La by Pr, up to 5.49 g/cm3. The calculated molar volumes and compactness values decrease and increase respectively by the substitution of Pr for La. Glass transition temperatures and microhardness increase upon the substitution by Pr, up to 1086 °C and 10.98 GPa, respectively. The refractive index increases upon the substitution by Pr up to 2.00.

  • 42.
    Irshad, Hafiz Musammil
    et al.
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Hakeem, Abbas Saeed
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Ahmed, Bilal Anjum
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ali, Sadaqat
    Imam Abdulrahman bin Faisal University, Saudi Arabia.
    Ali, Sameer
    University of Gujrat, Pakistan.
    Ehsan, Muhammad Ali
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Laoui, Tahar
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Effect of Ni content and Al2O3 particle size on the thermal and mechanical properties of Al2O3/Ni composites prepared by spark plasma sintering2018In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 76, p. 25-32Article in journal (Refereed)
    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.

  • 43.
    Karlsson, Stefan
    et al.
    Glafo, Sweden;University of Jena, Germany .
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Limbach, Renè
    University of Jena, Germany.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Wondraczek, Lothar
    University of Jena, Germany.
    Alkali salt vapour deposition and in-line ion exchange on flat glass surfaces2015In: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 56, no 6, p. 203-213Article in journal (Refereed)
    Abstract [en]

    This study suggests a different route for the modification of flat/float glass surfaces; i.e. exchange of ionic species originatingfrom in-line vapour deposition of salt as compared to the conventional route of immersing the glass in a molten saltbath. The aim of this work is to develop a more flexible and, eventually, more rapid process for improving the mechanicalstrength of flat glass by introducing external material into the surface. We discuss how chemical strengthening can beperformed through the application of potassium chloride on the glass surface by vapour deposition, and in-line thermallyactivated ion exchange. The method presented here has the potential to be up-scaled and to be used in in-line productionin the future, which would make it possible to produce large quantities of chemically strengthened flat glass at aconsiderably lower cost.

  • 44.
    Karlsson, Stefan
    et al.
    Glafo – the Glass Research Institute.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Chemical strengthening of flat glass by vapour deposition and in-line alkali metal ion exchange2014Report (Refereed)
    Abstract [en]

    Glass is a common material in the everyday life. It is widely used in a variety of applications e.g. architectural, automotive, containers, drinking vessels, displays, insulation and optical fibers due to its universal forming ability, transparency, chemical durability, form stability, hardness and relatively low price. Flat glass is a wide market of the glass industry and generally ninety percent of all flat glass produced worldwide is manufactured using the float forming process. There is a large market strive for thinner and stronger glass in order to reduce costs, save energy, reduce environmental footprint, find new applications and to improve the working environment for labour working with mounting flat glass. This study comprises the modification of flat/float glass surface by a novel route; exchange of ionic species originating from in-line vapour deposition of salt compared to the conventional route of immersing the glass in molten salt baths. The aim of this work is to develop a novel process in order to improve the mechanical strength of flat/float glass by introducing external material to the surface in a process with the obvious potential to be automatic in industrial processes. Chemical strengthening has been performed by applying potassium chloride to the glass surface by vapour deposition and thermally activated ion exchange. The method presented here is anticipated to be used in production in the future and would make it possible to produce larger quantities of chemically strengthened flat glass to a considerably lower cost.

  • 45. Karlsson, Stefan
    et al.
    Wondraczek, Lothar
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ion-exchange in Soda-Lime-Silicate Float Glass: Trends in Effective Diffusion Coefficients2014Conference paper (Refereed)
  • 46.
    Karlsson, Stefan
    et al.
    RISE Research Institutes of Sweden, Sweden.
    Wondraczek, Lothar
    University of Jena, Germany.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Kinetics of chemical strengthening and trends in effective diffusion coefficients2019In: 25th International Congresson Glass (ICG 2019); ABSTRACT BOOK: June 9–14, 2019Boston, Massachusetts USA, American Ceramic Society, 2019, p. 167-167Conference paper (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.

  • 47.
    Karlsson, Stefan
    et al.
    RISE Res Inst Sweden;Friedrich Schiller Univ Jena, Germany.
    Wondraczek, Lothar
    Friedrich Schiller Univ Jena, Germany.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Corning Inc, USA.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Trends in Effective Diffusion Coefficients for Ion-Exchange Strengthening of Soda-Lime-Silicate Glasses2017In: Frontiers in materials, ISSN 2296-8016, Vol. 4, article id UNSP 13Article in journal (Refereed)
    Abstract [en]

    Monovalent cations enable efficient ion-exchange processes due to their high mobility in silicate glasses. Numerous properties can be modified in this way, e.g., mechanical, optical, electrical, or chemical performance. In particular, alkali cation exchange has received significant attention, primarily with respect to introducing compressive stress into the surface region of a glass, which increases mechanical durability. However, most of the present applications rely on specifically tailored matrix compositions in which the cation mobility is enhanced. This largely excludes the major area of soda-lime-silicates (SLS) such as are commodity in almost all large-scale applications of glasses. Basic understanding of the relations between structural parameters and the effective diffusion coefficients may help to improve ion-exchanged SLS glass products, on the one hand in terms of obtainable strength and on the other in terms of cost. In the present paper, we discuss the trends in the effective diffusion coefficients when exchanging Na+ for various monovalent cations (K+, Cu+, Ag+, Rb+, and Cs+) by drawing relations to physicochemical properties. Correlations of effective diffusion coefficients were found for the bond dissociation energy and the electronic cation polarizability, indicating that localization and rupture of bonds are of importance for the ion-exchange rate.

  • 48.
    Möncke, Doris
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Wójcik, Natalia A.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gdańsk University of Technology, Poland.
    Palles, Damitris
    National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    IR and Raman study of oxy-nitride glasses2018In: Presented at Glass and the Meeting of Minds  (SGT18), Cambridge, UK (2nd -5th September 2018), 2018, p. 54-Conference paper (Refereed)
  • 49. Sellappan, Pathikumar
    et al.
    Ali, Sharafat
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Keryvin, Vincent
    Houizot, Patrik
    Tanguy, Rouxel
    Grins, Jekabs
    Esmaeilzadehb, Saeid
    Elastic properties and surface damage resistance of nitrogen-rich (Ca,Sr)–Si–O–N glasses2010In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 356, no 41-42, p. 2120-2126Article in journal (Refereed)
    Abstract [en]

    Ca and Sr-based oxynitride glasses with very high nitrogen content have been synthesized using metal hydrides as primary precursors. Values of Young's modulus, shear modulus, bulk modulus and Poisson's ratio were determined by means of ultrasonic echography. Vickers micro-indentation has been used to characterize hardness and indentation fracture toughness behaviour. Elastic moduli were found to increase linearly with nitrogen content, with the highest value of Young's modulus at 135 GPa, for a Ca-glass with 58 e/o of nitrogen. The Sr-glasses exhibit lower elastic moduli than Ca glasses. Poisson's ratio, hardness, indentation fracture toughness, crack initiation load and surface damage resistance were found to increase with increasing nitrogen content for both glass series.

  • 50.
    Wojcik, Natalia A.
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gdansk Univ Technol, Poland.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Polies, D.
    Natl Hellen Res Fdn, Greece.
    Kamitsos, E. I.
    Natl Hellen Res Fdn, Greec.
    Ghassemali, E.
    Jönköping University.
    Seifeddine, S.
    Jönköping University.
    Eriksson, M.
    Stockholm University.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Influence of synthesis conditions on glass formation, structure and thermal properties in the Na2O-CaO-P2O5 system doped with Si3N4 and Mg2018In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 494, p. 66-77Article in journal (Refereed)
    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.

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