Change search
Refine search result
1 - 4 of 4
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Shen, Zhijian
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Xiong, Yan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hoeche, Thomas
    Salamon, David
    Fu, Zhengyi
    Belova, Lyubov
    Ordered coalescence of nanocrystals: a path to strong macroporous nanoceramics2010In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 21, no 20, p. 205602-Article in journal (Refereed)
    Abstract [en]

    A versatile approach for integrating two apparently conflicting physical properties, high porosity and high mechanical strength, in polycrystalline bulks is established and demonstrated for the case of alumina ceramics. Macroporous alumina nanoceramics are synthesized by stimulating coalescence-mediated necking, which enables the formation of strong crystallographically coherent necks between adjacent grains. The work places a general emphasis on manipulating crystal growth on the nanoscale and on preparing highly porous polycrystalline bulk ceramics with improved mechanical rigidity.

  • 2. Yoon, Songhak
    et al.
    Dornseiffer, Juergen
    Xiong, Yan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Gruener, Daniel
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Iwaya, Shoichi
    Pithan, Christian
    Waser, Rainer
    Spark plasma sintering of nanocrystalline BaTiO(3)-powders: Consolidation behavior and dielectric characteristics2011In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 31, no 9, p. 1723-1731Article in journal (Refereed)
    Abstract [en]

    BaTiO(3) nanopowders prepared by two different wet chemical routes, one based on microemulsion-mediated synthesis (M-BT) and the other one on the alkoxide-hydroxide method (A-BT) were consolidated by spark plasma sintering (SPS). The densification process, the linear shrinkage rates and the relative densities achieved were strongly dependant on the synthetic route. The results show that fully densified BaTiO(3) ceramics with a grain size of about 200 nm can be obtained in both cases by controlling the sintering temperature during the SPS process. The study of dielectric properties revealed that M-BT derived ceramics show higher permittivity values compared to those obtained for A-BT. The influence of the barium/titanium ratio on the sintering behavior and the dielectric properties is discussed.

  • 3. Yoon, Songhak
    et al.
    Dornseiffer, Juergen
    Xiong, Yan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Grüner, Daniel
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Iwaya, Shoichi
    Pithan, Christian
    Waser, Rainer
    Synthesis, spark plasma sintering and electrical conduction mechanism in BaTiO(3)-Cu composites2011In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 31, no 5, p. 773-782Article in journal (Refereed)
    Abstract [en]

    BaTiO(3)-Cu composite powders were prepared via an alkoxide-mediated synthesis approach. As-synthesized BaTiO(3) nanoparticles were as small as 40 nm and coated partially larger Cu particles of approximately 1 mu m in size. Thermogravimetric analysis (TGA) and dilatometry revealed a gradual increase in weight loss and retarded shrinkage with the increase of Cu addition. BaTiO(3)-Cu composites were successfully densified by spark plasma sintering (SPS). The microstructures show an average grain-size for BaTiO(3) of around 100 nm and a crystallite size of about 1 mu m for the Cu inclusions. The AC conductivity of the BaTiO(3)-Cu composites increased with increasing Cu content or with temperature. The dominant electrical conduction mechanism in SPSed BaTiO(3)-Cu composites changed from migration of oxygen vacancies to band conduction of trapped electrons in oxygen vacancies with the increase of Cu content.

  • 4. Yoon, Songhak
    et al.
    Pithan, Christian
    Waser, Rainer
    Dornseiffer, Juergen
    Xiong, Yan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Gruner, Daniel
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Iwaya, Shoichi
    Electronic Conduction Mechanisms in BaTiO3-Ni Composites with Ultrafine Microstructure Obtained by Spark Plasma Sintering2010In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 93, no 12, p. 4075-4080Article in journal (Refereed)
    Abstract [en]

    Spark plasma sintering (SPS) was used to densify BaTiO3-Ni composite powders to relative densities above 92.8%. With the increasing Ni content, a decrease in relative density is observed, suggesting that Ni hampers the consolidation process. The microstructures of the BaTiO3-Ni composites were of duplex character. The crystallite size of the BaTiO3-grains was around 100 nm in average. The ceramic matrix phase of BaTiO3 surrounded Ni inclusions of approximately 1 mu m in diameter that were completely incorporated without the formation of any elongated metallic filaments. The ac conductivity of these BaTiO3-Ni composites increased with increasing Ni content and with temperature. The dominant conduction mechanisms in SPSed BaTiO3-Ni composites showed quite a complicated behavior. A gradual change from band conduction of trapped electrons in oxygen vacancies to a hopping-type motion of small polarons between Ti4+ and Ti3+ is suggested to occur, when the Ni content increases. The influence of oxygen vacancies and other lattice defects on the electrical properties of BaTiO3-Ni composites is discussed.

1 - 4 of 4
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf