Affiliation:
1. PPGECM - Postgraduate Program in Materials Engineering and Science, Department of Materials Engineering, UEPG - State University of Ponta Grossa, Ponta Grossa PR, Brazil
Abstract
Starch consolidation casting (SCC) technique was successfully employed to
produce both porous alumina and graded porous alumina ceramics. The solid
content in the alumina suspension was maintained at 40 vol.%, with potato
starch varying from 5 to 15%. Structures of the porous alumina (monolithic)
samples obtained by SCC and uniaxial pressing were compared. In addition,
the influence of the SCC consolidation temperature and the starch content
were evaluated in the monolithic samples, while the consolidation
temperature and the number of layers numbers were evaluated in the graded
samples. The lower SCC consolidation temperature resulted in lower linear
shrinkage and a slight increase in total porosity due to the increased pore
size. The compressive strength values for the monolithic samples ranged from
60 to 200MPa, which can be considered high when compared to previous works.
The graded samples exhibited porosity variations across layers and
interfaces were free of cracks and imperfections. Linear shrinkage was the
same for the adopted consolidation temperature and the porosity was slightly
higher for the 3-layer samples. They achieved strength of 60MPa with
fracture mode parallel to the applied load.
Publisher
National Library of Serbia