The gelcasting method was used to form gastight Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 samples proposed for use as proton-conducting electrolytes in solid oxide fuel cells. Methylcellulose was used as an environmentally friendly shaping agent for Ba 0.95-Ca 0.05 Ce 0.9 Y 0.1 O 3 powder in an ethanol solution. Samples of Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 were also prepared from the same powder via traditional isostatic pressing, as a reference for cast samples, and sintered in the same conditions. Comparative studies of the physicochemical properties of Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 electrolytes, formed by means of these two methods and then sintered at 1550°C for 2.5 h, were presented and discussed. Using the X-ray diffraction method, only the pure orthorhombic phase of BaCe 0.9 Y 0.1 O 3 was detected in the Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 powder, as well as in the Ba 0.95-Ca 0.05 Ce 0.9 Y 0.1 O 3 sintered pellets formed via both gelcasting (A) and isostatic pressing (B). Thermal effects occurring during heating of methylcellulose, as well as ceramic Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 powder, dried cast samples obtained from the prepared slurry, and sintered Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 samples, were examined by differential scanning calorimetry, differential thermal analysis, thermogravimetric analysis, and evolved gas analysis of volatile products using a quadrupole mass spectrometer. The measurements were performed within the temperature range of 20-1200°C in air. Based on dilatometric tests, it was found that the Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 cast samples exhibited slightly higher degree of sinterability than the 5CBCY samples obtained by isostatic pressing. In comparison with pressed pellets, higher values of total electrical conductivity in air or in a gas mixture of 5% H 2 in Ar were also attained for Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 cast samples. The Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 samples were used to construct oxygen-hydrogen electrolytes for solid oxide fuel cells. The results of the electrochemical performance of solid oxide fuel cells with Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 electrolytes were comparable to the data in the literature on BaCe 0.9 Y 0.1 O 3 electrolytes. An electrochemical study of a Ba 0.5 Sr 0.5-Co 0.8 Fe 0.2 O 3-d |Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 interface was also performed. Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-d appears to be a suitable cathode material for a Ba 0.95 Ca 0.05 Ce 0.9 Y 0.1 O 3 electrolyte.
ZrO 2 GELCAST FOAMS COATED WITH APATITE LAYERSIn this work, gel-casting of foams method was used to produce ZrO 2 porous ceramics. The obtained foams with total porosity of 89.5 vol% were composed of approximately spherical cells having the mean diameter of 537 ± 153 μm interconnected by circular cell windows having the mean diameter of 152 ± 82 μm. Next, the ZrO 2 foams were coated with fluorapatite (FA) and hydroxyapatite (HA) layers by slurry infiltration. The intermediate fluorapatite (FA) layer was introduced to prevent the chemical reactions between ZrO 2 and HA at high temperatures during sintering process. The ZrO 2 samples containing only HA coatings, were also tested, for comparison. The obtained ceramic biomaterials were subjected to in vitro tests in the simulated body fluid (SBF) solution. The results show that the ZrO 2 foams with FA/HA layers possessed better bioactivity than the foams with the HA/HA coating.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.