Fabrication of SiC ceramic foams with light weight and ultrahigh strength by a direct foaming method
The unique cellular microstructure of porous ceramics has made them favourable for a wide variety of applications in various industries. One such method of making these porous ceramics is by producing stabilised wet foam via direct foaming method. In this project, silicon carbide (SiC) particl...
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| Format: | Final Year Project |
| Language: | English |
| Published: |
Nanyang Technological University
2022
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| Online Access: | https://hdl.handle.net/10356/156783 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | The unique cellular microstructure of porous ceramics has made them
favourable for a wide variety of applications in various industries. One such method
of making these porous ceramics is by producing stabilised wet foam via direct
foaming method. In this project, silicon carbide (SiC) particles were dispersed in an
epoxy resin to form a slurry or suspension, and subsequently frothed by using a
cationic and anionic surfactant, Dodecyl Trimethyl Ammonium Chloride (DTAC)
and Sodium Dodecyl Sulphate (SDS), respectively. The consolidated foam was cast
and allowed to cure before debinding the organic binders, followed by sintering to
form the final porous ceramic. The effects of the types of surfactants and their
concentration on the foam rheological behaviour, pore size, porosity, density, and
projected strength of the ceramic foams has been systematically studied. SDS
assisted direct foaming method can produce ceramic foams with a wide range of
porosity and pore sizes, varying in 76 – 88% and 90 – 165 µm, respectively.
Comparatively, the DTAC assisted foaming method has less variation in the porosity
and pore size, changing between 64 – 68 % and 55 – 80 µm, respectively. With
DTAC as the surfactant being used at a concentration of 0.72 wt.% to the weight of
SiC dry powder, the sintered sample has porosities up to 67% with an average pore
size of ~56 µm and a predicted compressive strength of 32.5 MPa, which brings a
good balance of strength and interconnectivity of pores. This brings great potential to
enhance the capabilities of porous SiC ceramics for various engineering applications
in harsh environments. |
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