Ceramic thin plates are widely utilized in various advanced technologies, such as fuel cells and heat dissipation substrates, due to their high mechanical strength and thermal conductivity. However, the trend of thinning ceramic plates increases warpage, which can critically affect product quality and reliability. Therefore, understanding and accurately measuring this warpage has become increasingly important. In this study, a non-contact measurement method, the light sectioning technique, was applied to measure the warpage of thin ceramic plates with a half-cell (anode/electrolyte) structure for solid oxide fuel cells (SOFC) by varying their area and thickness. The relationship between the physical properties of the thin plates and the warpage was analyzed. Additionally, a comparative analysis was conducted to evaluate warpage errors caused by compressive loads during the traditional contact measurement process. Finally, to verify the reliability of the non-contact measurement method, four types of non-contact measurement techniques - light sectioning technique, laser displacement measurement, optical confocal technique, and white-light interferometry technique - were used to compare warpage data by orientation. The results were also compared with those from contact measurement methods to analyze the average warpage values. Through this, the superiority and high reliability of the non-contact measurement method were demonstrated.
It is necessary for ferrite sheets to be fabricated with high packing density for excellent electrical properties and high strength. In this study, the relationship between the warpage and the packing density of ferrite green sheet, was investigated with amount variation of organic additives. With 0.4 wt% of dispersant, the packing density was about 48% and warpage appeared 0.5~1.3 ㎜ high. With 1.4 wt% of dispersant, the packing density increased up to 57% and warpage appeared 0.8~2.1 ㎜ high. With high packing density, warpage appeared along the edges of specimen, while with low packing density, deformation appeared over whole specimen inhomogeneously. It is thought that inhomogeneous deformation after sintering came from the inhomogeneity in green sheet prepared with badly dispersed slurry. With good homogeneity in green sheet from well-dispersed slurry, isotropic shrinkage is thought to have occurred along the distance from center to edges of specimen during sintering.
A layered planer SOFC module was designed from planar-type SOFC. It was prepared by multi-layered ceramic technology. To form the cathode and the anode in the layered structure, reliable channels should be made on the both side of electrolyte perpendicularly. However, monolithic SOFC using multi-layered ceramic technology hasn`t been studied another group, and the warpage of electrolyte in the channel, also, hasn`t been studied, when electrode is printed on the electrolyte. In this study, the channels are prepared with electrode printing, and their warpage are evaluated. In the case of YSZ without electrode, the warpages are nothing in the limit of measurement using optical microscope. The warpage of ``YSZ-NiO printed`` increases than that of ``NiO printed``, and also, the case of ``double electrode printed`` is similar to ``YSZ-NiO printed``. It is thought that, in the printed electrolyte, the warpage is related to the difference of the sintering behavior of each material.