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Effect of starting PMMA content on microstructure and properties of gel casting BN/Si3N4 ceramics with spherical-shaped pore structures
- Source :
- Journal of Materials Science. 48:7974-7980
- Publication Year :
- 2013
- Publisher :
- Springer Science and Business Media LLC, 2013.
-
Abstract
- By gel casting with polymethylmethacrylate microbeads (PMMA) as pore-forming agent, porous boron nitride/silicon nitride (BN/Si3N4) composite ceramics were successfully prepared. The obtained ceramic shows bimodal hierarchical structures that composed of spherical-shaped micro pores depending on PMMA content and irregular sub-micro pores formed by the stacking of ceramic particles. Porosity of the porous BN/Si3N4 ceramics can be well controlled from 53.0 to 60.6 % by the PMMA content from 10 to 40 wt%, as well as the mechanical and dielectric properties. Effect of PMMA content on phase composition and the relationship between microstructure and the basic properties of the porous BN/Si3N4 ceramics was discussed in detail. Microstructure analysis reveals that the sub-micro pores acted as channels between micro pores. BN particles have a relatively denser distribution on the wall of spherical-shaped micro pores with a window between micro and sub-micro pores, and resulting in a half-closed micro pore structure, which is meaningful for material design with concentration of BN particles on the wall of pore structure.
Details
- ISSN :
- 15734803 and 00222461
- Volume :
- 48
- Database :
- OpenAIRE
- Journal :
- Journal of Materials Science
- Accession number :
- edsair.doi...........bf328924eb56f56d472199a14d6eefbc