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Lightweight mullite ceramics with controlled porosity and enhanced properties prepared by SLS using mechanical mixed FAHSs/polyamide12 composites
- Source :
- Ceramics International. 45:20803-20809
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- It is difficult to fabricate lightweight ceramic parts with well pore control and high structural complexity. In this paper, lightweight mullite ceramics with controlled porosity and enhanced properties were prepared via selective laser sintering (SLS) using mechanical mixed FAHSs/PA12 (Fly ash hollow spheres/polyamide 12) composites. Crack-free ceramic green bodies were prepared through SLS using the optimized process parameters: 7.2 W in laser power, 1600 mm/s in scanning velocity and 0.11 mm in hatch spacing. The influence of PA12 content on porosity, size distribution of open pore, mechanical properties and thermal property were studied. The pores in ceramic foams consisted of the closed pores from sphere core-shell structures, the open pore channels in the middle of stacking spheres and the special gaps in the middle of spheres related to SLS. It was found that the total porosity of lightweight mullite ceramics increased slightly from 85.1 ± 0.3% to 85.2 ± 0.4% with PA12 content increasing from 10 to 15 wt%, and then increased obviously to 86.7 ± 0.5% with further increasing PA12 addition to 25 wt%. This porosity increase was mainly attributed to the open pores resulted from the PA12 addition. The PA12 were firstly filled into the interspaces between stacking spheres and when the stacking volume reached the maximum, the interspaces expanded to form the special gaps between spheres with further PA12 addition. Thus, the size distribution of open pore in lightweight FAHS ceramics increased from 31.5 to 34.5 μm gradually with PA12 content increasing from 10 to 25 wt%. Finally, low thermal conductivity of 0.06 W/(m·K) was obtained, which probably resulted from the high porosity and the special pore structures of the SLS-formed ceramic foams. The understanding of the unique pore structures and microstructures will help the pore control and strength improvement of SLS-formed ceramic foams using the ceramic hollow spheres.
- Subjects :
- 010302 applied physics
Materials science
Process Chemistry and Technology
Stacking
Mullite
02 engineering and technology
021001 nanoscience & nanotechnology
Microstructure
01 natural sciences
Surfaces, Coatings and Films
Electronic, Optical and Magnetic Materials
law.invention
Selective laser sintering
Thermal conductivity
law
visual_art
0103 physical sciences
Polyamide
Materials Chemistry
Ceramics and Composites
visual_art.visual_art_medium
Ceramic
Composite material
0210 nano-technology
Porosity
Subjects
Details
- ISSN :
- 02728842
- Volume :
- 45
- Database :
- OpenAIRE
- Journal :
- Ceramics International
- Accession number :
- edsair.doi...........1fe98477bac13c52faa185961cdaf930