Abstract
The effect of additives on paste rheology was investigated for preparation of porous ceramics with unidirectionally aligned cylindrical pores. Ammonium poly-carboxylic acid (APA) used as a dispersant and it was adsorbed on alumina powder surface. The adsorption isotherm of APA was fitted by Langmuir equation. The saturated monolayer adsorption was 5.9 mg/g. The apparent viscosity became a minimum at 0.8 mass % of APA corresponding to 71.2 mPa·s. This APA amount of 5.6 mg/g, is in good agreement with the observed APA amount. Since the nylon 66 fibers (0-35 vol. %) mixed with the alumina powder have a strong interaction with each other, they became twisted and agglomerated. This agglomeration increased with increasing fiber content but decreased by adding oleic acid. The pastes with added oleic acid were capable of being extruded at higher pressure. The obtained porous alumina ceramics showed highly oriented cylindrical pores parallel to the extrusion direction. The pore orientation was higher in the oleic acid added pastes than those without oleic acid. The added nylon 66 fibers are mostly converted to pores while maintaining the original shape after sintering. The pore size distribution of the obtained porous ceramics measured by mercury porosimetry method showed a peak at about 4 μm which is apparently smaller than that observed in the SEM photographs and the obtained result is considered to be corresponding to the necks formed by fiber contacts.
| Original language | English |
|---|---|
| Pages (from-to) | 269-273 |
| Number of pages | 5 |
| Journal | Journal of Porous Materials |
| Volume | 13 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Aug 2006 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Chemistry (miscellaneous)
- Physical and Theoretical Chemistry
- Materials Science(all)
- Catalysis
Cite this
Effect of dispersant on paste rheology in preparation of porous alumina with oriented pores by extrusion method. / Isobe, Toshihiro; Kameshima, Yoshikazu; Nakajima, Akira; Okada, Kiyoshi; Hotta, Yuji.
In: Journal of Porous Materials, Vol. 13, No. 3, 08.2006, p. 269-273.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of dispersant on paste rheology in preparation of porous alumina with oriented pores by extrusion method
AU - Isobe, Toshihiro
AU - Kameshima, Yoshikazu
AU - Nakajima, Akira
AU - Okada, Kiyoshi
AU - Hotta, Yuji
PY - 2006/8
Y1 - 2006/8
N2 - The effect of additives on paste rheology was investigated for preparation of porous ceramics with unidirectionally aligned cylindrical pores. Ammonium poly-carboxylic acid (APA) used as a dispersant and it was adsorbed on alumina powder surface. The adsorption isotherm of APA was fitted by Langmuir equation. The saturated monolayer adsorption was 5.9 mg/g. The apparent viscosity became a minimum at 0.8 mass % of APA corresponding to 71.2 mPa·s. This APA amount of 5.6 mg/g, is in good agreement with the observed APA amount. Since the nylon 66 fibers (0-35 vol. %) mixed with the alumina powder have a strong interaction with each other, they became twisted and agglomerated. This agglomeration increased with increasing fiber content but decreased by adding oleic acid. The pastes with added oleic acid were capable of being extruded at higher pressure. The obtained porous alumina ceramics showed highly oriented cylindrical pores parallel to the extrusion direction. The pore orientation was higher in the oleic acid added pastes than those without oleic acid. The added nylon 66 fibers are mostly converted to pores while maintaining the original shape after sintering. The pore size distribution of the obtained porous ceramics measured by mercury porosimetry method showed a peak at about 4 μm which is apparently smaller than that observed in the SEM photographs and the obtained result is considered to be corresponding to the necks formed by fiber contacts.
AB - The effect of additives on paste rheology was investigated for preparation of porous ceramics with unidirectionally aligned cylindrical pores. Ammonium poly-carboxylic acid (APA) used as a dispersant and it was adsorbed on alumina powder surface. The adsorption isotherm of APA was fitted by Langmuir equation. The saturated monolayer adsorption was 5.9 mg/g. The apparent viscosity became a minimum at 0.8 mass % of APA corresponding to 71.2 mPa·s. This APA amount of 5.6 mg/g, is in good agreement with the observed APA amount. Since the nylon 66 fibers (0-35 vol. %) mixed with the alumina powder have a strong interaction with each other, they became twisted and agglomerated. This agglomeration increased with increasing fiber content but decreased by adding oleic acid. The pastes with added oleic acid were capable of being extruded at higher pressure. The obtained porous alumina ceramics showed highly oriented cylindrical pores parallel to the extrusion direction. The pore orientation was higher in the oleic acid added pastes than those without oleic acid. The added nylon 66 fibers are mostly converted to pores while maintaining the original shape after sintering. The pore size distribution of the obtained porous ceramics measured by mercury porosimetry method showed a peak at about 4 μm which is apparently smaller than that observed in the SEM photographs and the obtained result is considered to be corresponding to the necks formed by fiber contacts.
UR - http://www.scopus.com/inward/record.url?scp=33744513174&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33744513174&partnerID=8YFLogxK
U2 - 10.1007/s10934-006-8015-4
DO - 10.1007/s10934-006-8015-4
M3 - Article
AN - SCOPUS:33744513174
VL - 13
SP - 269
EP - 273
JO - Journal of Porous Materials
JF - Journal of Porous Materials
SN - 1380-2224
IS - 3
ER -