• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.90-94
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• 1995

In Sr-ferrite system, it has been attempted to inhibit the abnormal grian growth using Sr-ferrite powders synthesized by molten salt method as the matrix and the seeds, respectively. At each sintering temperature, the addition of seed more than 15% suppressed the abnormal grain growth, and the uniform microstructure resulted. Particularly, at 12$25^{\circ}C$, it was observed that the maximum number of the abnormal grain growth nuclei was achieved since the abnormal grain growth was suppressed even by the addition of 10% seed.

• Journal of the Korean Ceramic Society
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• v.27 no.4
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• pp.481-486
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• 1990

Microstructure of polycrystalline Lead Telluride was controlled by the change of sintering conditions. Three properties which determine the thermoelectric figure of merit of the material were measured in the temperature range of 300-650K in order to investigate the effect of each sintering condition on the thermoelectric efficiency. Based on the observed experimental results, defect structure is concluded to be more important than microstructure though both can be controlled by processing variables.

• Journal of the Korean Ceramic Society
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• v.29 no.8
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• pp.593-600
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• 1992

Through sol-gel processing, Inorganic-organic composite was obtained. The influence of water content used in hydrolysis on the bonding state, microstructure, strength, and elongation into IR, NMR, Tg, etc. As the water content was increased, the bonds between inorganic Si-(OH) and organic Si-(OH) increased, and relatively denser microstructure was formed. Tensile strength and elongation decreased with amount of water content.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.156-158
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• 2002

BSCCO tpaes with insulating ceramic barriers such as Zr$O_{2}$, $Al_{2}$$CO_{3}$, and Sr$CO_{3}$ were fabricated and their electrical properties were evaluated. Each filament was dip coated with ceramic slurries and then made 19 multifilamentary tapes by the “powder-in-tube” process. Microstructural investigation showed that filaments were completely decoupled each other and had a significant sausage effect. The critical current of coated tapes was reduced compared to that of non coated one, and its reduction was varied with the coating materials. For tapes with coated with Sr$CO_{3}$, the critical current was measured to be 7.2 A which was 44% reduction to that of non coated one. This reduction is believed to be due to the formation of sausage effect and non-uniform microstructure.

• Ceramist
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• v.22 no.4
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• pp.368-380
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• 2019

A ceramic is used as a key material in various fields. Accordingly, the use of scanning electron microscopy is increased for the purpose of evaluating the reliability and defects of advanced ceramic materials. The scanning electron microscope is developed to overcome the limitations of optical microscopy and uses accelerated electrons for imaging. Various signals such as SE, BSE and characteristic X-rays provide useful information about the surface microstructure of specimens and, the content and distribution of chemical components. The development of electron guns, such as FEG, and the improved lens system combined with the advanced in-lens detectors and STEM-in-SEM system have expanded the applications of SEM. Automated SEM-EDS analysis also greatly increases the amount of data, enabling more statistically reliable results. In addition, X-ray CT, XRF, and WDS, which are installed in scanning electron microscope, have transformed SEM a more versatile analytical equipment. The performance and specifications of the scanning electron microscope to evaluate ceramics were reviewed and the selection criteria for SEM analysis were described.

• Journal of the Korean Ceramic Society
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• v.43 no.8 s.291
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• pp.498-503
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• 2006

A gas turbine blade with thermal barrier ceramic coating is operated at high temperature to increase engine efficiency. Recently, thermal barrier characteristics have been improved by advanced coating technology through microstructure control and increase of adhesion force of the coating layer. More advanced coating materials, rare earth zircon ate ceramics have been studied for replacing YSZ coatings as thermal barrier coatings. In this study, $La_2O_3,\;HfO_2,\;CeO_2,\;Gd_2O_3$ and pure or yttria stabilized zirconia were prepared. Microstructure analysis and the evaluation of mechanical properties such as Hertzian indentation and hardness test were performed.

• Carbon letters
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• v.7 no.1
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• pp.27-33
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• 2006

Carbon-ceramic composites were fabricated by using fly ash and PANOX fibers as reinforcement. Fly ash, because of its small size particles e.g. submicron to micron level can be effectively dispersed along with fibrous reinforcements. Phenolic resin was used as carbon precursor. Both dry as well as wet methods were used for forming composites. The resulting composites were characterized for their microstructure, thermal and mechanical properties. The microstructure and mechanical properties of composites are found to be dependent on type of the fly ash, fibrous reinforcements as well as processing parameters. The addition of fly ash improves hardness and the fibers, which get co-carbonized on heat treatment, increase the flexural strength of the carbon-ceramic composites. Composites with dual reinforcement exhibit about 30-40% higher strength as compared to the composites made with single reinforcement, either with fly ash as filler or with chopped fibers.

• Journal of the Korean Ceramic Society
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• v.33 no.12
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• pp.1347-1352
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• 1996

• Journal of the Korean Ceramic Society
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• v.33 no.6
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• pp.686-692
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• 1996

• Journal of the Korean Ceramic Society
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• v.33 no.11
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• pp.1187-1194
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• 1996