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Detailed Program
Paper Number : ST-O04 |
Time Frame : 16:50~17:10 |
Presentation Date : Thurseday, 27, November |
Session Name : Structural Ceramics |
Session Chair 1# : Hai-Doo Kim |
Session Chair 2# : Junich tatami |
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Co-dispersion system of ZrB2-SiC in non-aqueous solvent |
Jin Soon HAN |
Hanyang university |
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ZrB2 has been studied for several decades. The excellent properties of ZrB2 such as low density, high thermal conductivity, low thermal expansion, good strength and hardness make ZrB2 attractive candidate for Ultra High Temperature Ceramics (UHTC). However ZrB2 is easily oxidized to ZrO2 from its surface which has weak and worse properties than ZrB2. Thus, it is used with SiC as a composite, which oxidizes instead of ZrB2 in oxidizing conditions, forms the sticky oxidation resistance silica layer and prevents ZrB2 from attaching O2 and oxidization, without any negative effect to properties of ZrB2. In spite of the benefits of ZrB2-SiC system, some problems remain in its manufacturing process. Naturally, ZrB2 and SiC are hard to be dispersed and this causes unexpected agglomeration and lager grains during heating process. These larger grains are not covering ZrB2 perfectly which means ZrB2 can be damaged by oxidation due to unequal oxidation resistance. Also, this lager grain Accordingly, the uniform distribution with smaller grain size have been required in the ZrB2-SiC composite system, and this can be achieved with approach about the colloidal dispersion and prevent agglomeration of ZrB2 and SiC nano-particle in non-aqueous solvent by chemical route.
In this study, stable colloidal dispersion system was performed for the wide application of ZrB2-SiC nano particle system. This dispersion system was performed in non-aqueous solvent to prevent oxidation occurred by water which contained in aqueous solution. Especially oleic acid was introduced as dispersant for maximization of steric effect. Also N-Methyl-2-pyrrolidone (NMP) was selected for polar aprotic solvents by Hansen solubility parameter for its high affinity with powder and dispersion, and maximization of polarity. The amount of powder loading was fixed at 40 wt% and the different amount of dispersant (none to 3 wt%) was added. The solutions were analyzed by FT-IR, particle size distribution, Energy Dispersive X-ray Spectroscopy (EDS), Zeta-potential in terms of surface charge of powder, size and co-dispersion.
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