Change search
CiteExportLink to record
Permanent link

Direct 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
Rapid sintering of ceramics by intense thermal radiation
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Sintering is an important processing step for obtaining the necessary mechanical stability and rigidity of ceramic bulk materials. Both mass and heat transfer are essential in the sintering process. The importance of radiation heat transfer is significantly enhanced at high temperatures according to the well-known Stefan-Boltzmann’s law. In this thesis, we modified the pressure-less spark plasma sintering set-up to generate intense thermal radiation, aiming at rapid consolidation of ceramic bulk materials. This approach was named as “Sintering by Intense Thermal Radiation (SITR)” as only thermal radiation contributed.

Firstly, the heat and mass transfer mechanisms during the SITR process were studied by choosing zirconia ceramics as references. The results revealed that the multiple scattering and absorption of radiation by the materials contributed to the heat diffusion. The observed enhanced densification and grain growth can be explained by a multiple ordered coalescence of zirconia nanocrystals using high heating rates.

Secondly, the temperature distribution during the SITR process was investigated by both numerical simulation and experimental verifications. It showed that the radiator geometry, sample geometry and radiating area were influencing factors. Besides, the change of material and geometry of the radiators resulted in an asymmetric temperature distribution that favored the formation of SiC foams. The foams had gradient structures with different open porosity levels and pore sizes and size distributions.

Finally, ceramic bulk materials were successfully fabricated by the SITR method within minutes. These materials included dense and strong ZrO2 ceramics, Si3N4 foams decorated with one-dimensional nanostructures, and nasal cavity-like SiC-Si3N4 foams with hierarchical heterogeneities. Sufficient densification or formed strong necks were used for tailoring these unique microstructures. The SITR approach is well applicable for fast manufacture of ceramic bulk materials because it is clean and requires low energy consumption and properties can be controlled and tuned by selective heating, heating speed or temperature distribution.

Place, publisher, year, edition, pages
Stockholm: Department of Materials and Environmental Chemistry (MMK), Stockholm University , 2016. , 98 p.
Keyword [en]
Sintering, sintering by intense thermal radiation, spark plasma sintering, heat transfer, mass transfer, scattering, coalescence, densification, grain growth, numerical simulation, porous ceramic, foaming, nanostructure, hierarchical heterogeneities, permeability
National Category
Materials Engineering Ceramics
Research subject
Materials Chemistry
Identifiers
URN: urn:nbn:se:su:diva-124131ISBN: 978-91-7649-325-0 (print)OAI: oai:DiVA.org:su-124131DiVA: diva2:882401
Public defence
2016-02-12, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.

 

Available from: 2016-01-20 Created: 2015-12-14 Last updated: 2017-02-20Bibliographically approved
List of papers
1. Sintering by intense thermal radiation (SITR): A study of temperature distribution by simulation and experiments
Open this publication in new window or tab >>Sintering by intense thermal radiation (SITR): A study of temperature distribution by simulation and experiments
2015 (English)In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 35, no 12, 3303-3309 p.Article in journal (Refereed) Published
Abstract [en]

The modeling and a confirming experimental study of a sintering process by using intense thermal radiation (SITR) is demonstrated. Experiments were conducted in a modified spark plasma sintering set-up for the purpose of rapid consolidation of porous SIC ceramics. A finite element method based software package, COMSOL Multiphysics, was employed to simulate the temperature distributions with two different die geometries. Experimental verifications were performed by sintering of SiC foams and measuring the temperature differences between two fixed points on the die and samples at 1000-1800 degrees C. SiC foams sintered under two geometries with 10 mm' dwell resulted in the formation of grain necks. The compressive strengths are 19.2 +/- 0.7 MPa (65.0 +/- 0.1 vol% porosity) and 15.3 +/- 1.9 MPa (69.0 +/- 0.3 vol% porosity), respectively. The simulation and experimental results showed that the temperature distributions are strongly related to these geometries.

Keyword
Spark plasma sintering, Simulation, Porous material, Silicon carbide, Sintering by intense thermal radiation (SITR)
National Category
Materials Engineering Chemical Sciences
Research subject
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-119279 (URN)10.1016/j.jeurceramsoc.2015.03.021 (DOI)000357356000014 ()
Available from: 2015-08-05 Created: 2015-08-03 Last updated: 2017-12-04Bibliographically approved
2. Rapid sintering of ceramics with gradient porous structure by asymmetric thermal radiation
Open this publication in new window or tab >>Rapid sintering of ceramics with gradient porous structure by asymmetric thermal radiation
2015 (English)In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 98, no 12, 3631-3634 p.Article in journal (Refereed) Published
Abstract [en]

In this study, thermal radiation was employed for sintering silicon carbide foams that achieved a gradient porous structure. The simultaneous use of graphite and carbon fiber reinforced carbon composite (Cf/C) radiators resulted in an axial temperature gradient of ~600°C along the cylindrical sample, as confirmed by both numerical simulation and experimental measurement. By sintering the cylinder top at 1600°C for 5 min, the porous SiC body achieved an axial pore size gradient from ~106 ± 36 μm to ~250 ± 84 μm and an open porosity from 41.4 to 79.8 vol%. This work indicates the potential of sintering by intense thermal radiation technique for rapid manufacturing functionally graded materials through asymmetric assembly of thermal radiators.

National Category
Ceramics
Research subject
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-124053 (URN)10.1111/jace.13926 (DOI)000368076500004 ()
Available from: 2015-12-11 Created: 2015-12-11 Last updated: 2017-12-01Bibliographically approved
3. Sintering by Intense Thermal Radiation (SITR): heat and mass transfer
Open this publication in new window or tab >>Sintering by Intense Thermal Radiation (SITR): heat and mass transfer
Show others...
(English)Article in journal (Refereed) Submitted
National Category
Ceramics
Research subject
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-124055 (URN)
Available from: 2015-12-11 Created: 2015-12-11 Last updated: 2015-12-15Bibliographically approved
4. Dense and strong ZrO2 ceramics fully densified in < 15 min
Open this publication in new window or tab >>Dense and strong ZrO2 ceramics fully densified in < 15 min
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-124197 (URN)
Available from: 2015-12-15 Created: 2015-12-15 Last updated: 2015-12-15Bibliographically approved
5. Rapid sintering of silicon nitride foams decorated with one-dimensional nanostructures by intense thermal radiation
Open this publication in new window or tab >>Rapid sintering of silicon nitride foams decorated with one-dimensional nanostructures by intense thermal radiation
Show others...
2014 (English)In: Science and Technology of Advanced Materials, ISSN 1468-6996, E-ISSN 1878-5514, Vol. 15, no 4, 045003Article in journal (Refereed) Published
Abstract [en]

Silicon nitride foams were prepared by direct foaming and subsequent rapid sintering at 1600 °C. The intense thermal radiation generated under the pressureless spark plasma sintering condition facilitated necking of Si3N4 grains. The prepared foams possessed a porosity of ~80 vol% and a compressive strength of ~10 MPa, which required only ~30 min for the entire sintering processes. Rapid growth of one-dimensional SiC nanowires from the cell walls was also observed. Thermodynamic calculations indicated that the vapor–liquid–solid model is applicable to the formation of SiC nanowires under vacuum.

Keyword
silicon nitride, foam, spark plasma sintering, nanowire, thermodynamics
National Category
Ceramics
Research subject
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-109796 (URN)10.1088/1468-6996/15/4/045003 (DOI)
Available from: 2014-12-01 Created: 2014-12-01 Last updated: 2017-12-05Bibliographically approved
6. Preparation of nasal cavity-like SiC-Si3N4 foams with a hierarchical pore architecture
Open this publication in new window or tab >>Preparation of nasal cavity-like SiC-Si3N4 foams with a hierarchical pore architecture
2015 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 35, 27891-27900 p.Article in journal (Refereed) Published
Abstract [en]

Rigid SiC-Si3N4 foams with hierarchical porosity were prepared through protein-based gel-casting followed by radiant sintering in a modified spark plasma sintering (SPS) set-up. The porous bodies sintered at 1500-1700 degrees C for only 10 minutes achieved a compressive strength of 15-21 MPa while keeping a porosity of 60-70 vol%. Gradient porous structures, with pore sizes ranging between 1 to 100 mm, were intersected by the growth of hybrid SiC and Si3N4 nanowires inside the pores resulting in a nasal cavity-like appearance. Gas permeability at room temperature (25 degrees C) and 600 degrees C was evaluated. Darcian permeabilities and non-Darcian permeabilities of all the prepared foams at room temperature fell within (0.354-1.55) x 10(-12) m(2) and (1.60-6.33) x 10(-8) m, respectively. Measurement of the Darcian and non-Darcian permeabilities at 600 degrees C were much higher, at 1.71 x 10(-11) m(2) and 2.68 x 10(-7) m, respectively. The microstructure, stability, gas flow properties and the green synthesis route reveal the potential of these ceramic foams to be used as industrial PM filters for airborne pollutions.

National Category
Chemical Sciences
Research subject
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-116561 (URN)10.1039/c5ra00766f (DOI)000351556100086 ()
Note

AuthorCount:4;

Available from: 2015-04-23 Created: 2015-04-21 Last updated: 2017-12-04Bibliographically approved

Open Access in DiVA

Rapid sintering of ceramics by intense thermal radiation(8719 kB)705 downloads
File information
File name FULLTEXT02.pdfFile size 8719 kBChecksum SHA-512
dfdec9081cd5b317ab748f8591bcec2f52ba0282021420e613fb8a2ad1776ea076435fa6fa59ff0813f2fe622880fafaad88c796048257018756e3a0d8a7e98c
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Li, Duan
By organisation
Department of Materials and Environmental Chemistry (MMK)
Materials EngineeringCeramics

Search outside of DiVA

GoogleGoogle Scholar
Total: 705 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 904 hits
CiteExportLink to record
Permanent link

Direct 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