Papers by Keyword: Sintering Shrinkage

Abstract: To explain the deformation during the co-sintering of NiO/YSZ-YSZ coating, the sintering shrinkage of NiO, NiO/YSZ and YSZ were measured by dilatometer. The coefficient of deformation variable (CDV, α) is defined to describe the difference of the sintering behaviors between the layers constrained.

Abstract: Spherical alumina powder and dispersant were mixed with distilled and deionized water, and ball milled to make alumina slurry. The slurry was dried in a high magnetic field to make a compact. Subsequently, the compact was cold-isostatic-pressed (CIP) to enhance the homogeneity in particle packing density. Anisotropy of shrinkage during sintering was examined for the alumina compacts in detail. Particle orientation existed in the spherical alumina powder compacts prepared in 10T, and made them shrink anisotropically during sintering. Sintering shrinkage was larger in the direction parallel to magnetic field direction (i.e., the c-axis direction of alumina crystal) than that in its perpendicular direction. The particle orientation structure in the compacts was confirmed with the immersion liquid method of polarized light microscope, and the grain alignment structure in the sintered bodies was also observed with X-ray diffraction, the c-plane was perpendicular to the magnetic field direction. On the other hand, isotropic sintering shrinkage occurred in the spherical alumina powder compacts prepared in 0T, which did not hold the particle orientation. The experimental results indicate that sintering shrinkage of spherical alumina powder compact depends on alumina crystal axis direction. Origin of the sintering shrinkage anisotropy for the spherical alumina powder compacts can be attributed to the particle orientation caused by high magnetic field.

Abstract: In the development of intermediate temperature solid oxide fuel cell (IT-SOFC), the anode supported thin electrolyte with higher conductivity than YSZ is an essential approach in recent years. In this work, we report our route that Ce0.8Sm0.2O1.9 (SDC) as electrolyte and porous NiO-SDC as anode substrate are prepared by a bi-layer tape casting and co-sintering process. The major effort was to adjust and control the shrinkage of the two material layers. It was found that only the specimens with less than 0.1% mismatching of the sintering shrinkage between two layers can result in the flat and crack free samples. In addition, high activity powders were the essential to obtain dense SDC electrolyte. Fuel cells with Sm0.5Sr0.5CoO3 as cathode were tested. The open circuit voltage (OCV) and the power density of the cells confirmed the full densification of the SDC electrolyte on the anode support.

Abstract: Symmetric three-layer alumina/zirconia/mullite composites have been prepared by tape casting and hot-pressing (20 MPa) at 1500°C for 2 h in argon. The hardness and Young’s modulus of the layered materials were evaluated using low load continuous depth-sensing indentation equipment (nanoindentation), appear to be affected by the formation of processing defects and residual stress.