Abstract: Recently, a novel processing route for fabricating microcellular ceramics has been
developed. The strategy for making the microcellular ceramics involves: (i) forming some shapes
containing a mixture of preceramic polymer, expandable microspheres and optional fillers by a
conventional ceramic forming method, (ii) foaming the compact by heating, (iii) cross-linking the
foamed body, and (iv) transforming the foamed body into microcellular ceramics by pyrolysis. The
flexural strength and compressive strengths of the microcellular ceramics were investigated; values
up to 30 MPa and 100 MPa, respectively, were obtained at room temperature. The superior
mechanical properties were attributed to homogeneous distribution of cells in microcellular ceramics.
Abstract: A novel Ni-YSZ anode with interpenetrating phase composite (IPC) structure was
developed using NiO-YSZ core-shell composite powder and evaluated in terms of microstructure,
electrical conductivity, thermal expansion and flexural strength. In comparison to conventional anode,
the anodic performance of IPC anode appeared to be more desirable for improving structural
reliability of SOFC unit cells and stacks. This study reveals that the anodic performance of IPC anode
can be readily tailored by controlling core-shell composite powder particles.
Abstract: Micro-tube type Gd-doped CeO2(CGO) reactor were prepared by hydrolysis of metal acetate
gel at room temperature. The size of anode tube was ca. 0.8mm in diameter, and length was
20mm after sintering at 1400°C. DC conductivity of the prepared dense CGO cell consisting
of 500nm grains was about 10 Ohm-cm at 600°C. Electrical power density of the micro-tube
fuel cell, which was coated both CGO electrolyte and CGO/La0.6Sr0.4Co0.2Fe0.8O3 cathode on
the surface of 40vol%NiO-CGO anode tube, was about 900mW/cm2 at 600°C under
30ml/min H2 gas flowing.
Abstract: Yttria stabilized zirconia (YSZ) films with the thickness of up to 12 μm were prepared on
alumina and NiO-YSZ substrates by electron beam physical vapor deposition (EB-PVD). The films
showed nano-scaled columnar structures depending on the substrate temperature. Electrical
conductivity of the YSZ films on alumina was also investigated at the temperature between 700 and
1000oC in oxidizing atmosphere. High activation energy of the conductivity (>1.03eV) indicated that
the conduction via grain boundary controlled the ionic conduction in the films prepared by EB-PVD.
La0.6Sr0.4CoO3-δ as a cathode was applied on the YSZ/NiO-YSZ in order to evaluate the performance
of the YSZ electrolyte.
Abstract: Dense 8mol% yttria-stabilized zirconia (8YSZ) consisting of submicrometer-sized grains
was prepared using spark plasma sintering (SPS) along with Al2O3 additives. The starting powder
with average particle size of 50nm was densified to 98% of the relative density with short sintering
time (5min) at 1200 while preserving a submicrometer grain size. The fracture toughness and
bending strength showed maximum values of 2.54MPam1/2 and 380MPa at 2vol% alumina-added
8YSZ, due mainly to the higher relative density and small grain size. The electrical conductivity of
2vol% alumina-added 8YSZ was 0.0278 S/cm at 700 in airThus, alumina additions in 8YSZ
using the SPS method are an effective process to improve the mechanical strength and electrical
Abstract: Porous composites containing ceramic fiber have been developed for the fabrication of
SOFC seals. They were fabricated using glass powder and alumino-silicate chopped fibers. Effect of
mixing ratios of ceramic fiber and glass on the leak rates and strength of the composite seals was
investigated. In addition, seal performance of commercial glasses was compared with that of
SiO2-BaO-B2O3 glass synthesized in this work. The leak rate of the composite seals containing 55
vol% glass was seven times higher than the one containing 75 vol% glass. The flexural strength of the
composite seals was reduced to one fourth of the initial value as the porosity increased from 1 to 29%.
The incorporation of alumino-silicate chopped fibers into a sealing glass degraded room temperature
strength and increased leak rates due to increase in porosity with increasing fiber content. The
viscosity of glass at the seal test temperature is presumed to affect the leak rate of the glass seal.