• Journal of the Korean Ceramic Society
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• v.37 no.8
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• pp.787-791
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• 2000

Samples with the nominal composition, Bi2-xGexSr2CaCu2O8＋$\delta$ (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared by the solid-state reaction method. We have studied the effect of substitution Ge for Bi and investigated the superconducting properties by changing oxygen content with Ge substitution. It was found that temperature difference, ΔK, between TCon and TCzero was considerably smaller in the samples prepared by the intermediate pressing method than that in the samples by the solid-state reaction method. We found the solubility limit of Ge to the 80 K single phase was around x=0.3. Within the solubility limit, lattice constant c decreased with the increase of x. In the region of the 80K single phase, the onset critical temperature TCon increased and excess oxygen content decreased with increase of x.

• Journal of the Korean Ceramic Society
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• v.37 no.7
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• pp.721-725
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• 2000

In this study, the dispersion stability of nano-sized CeO2 particles, synthesized by hydrothermal method in aqueous was evaluated from observing the surface potential behavior of CeO2 particle synthesized by solid state reaction. The isoelectric point(IEP) of nano-sized CeO2 synthesized by hydrothermal synthesis was found to be pH 9 contrary to the isoelectric point of micro-sized CeO2 synthesized by solid state reaction at pH 6.7. IEP was shifted to pH 2.0 as the addition of D-3019 from 0.1 to 1.0 wt%. The surface potential of CeO2 particles synthesized by hydrothermal synthesis was reduced as the addition of B-1001 used as a binder without change of IEP because the absorption of B-1001 polymer on the CeO2 particles shifted the shear plane of CeO2 particles outward away from the surface. This surface potential behavior was well correlated with the dispersion stability of slurry.

• The Korean Journal of Ceramics
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• v.2 no.1
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• pp.19-24
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• 1996

The phase distribution and interface chemistry by the solid-state reaction between SiC and nickel were studied at temperatures between $550 \;and\; 1250^{\circ}C$ for 0.5-100 h. The reaction with the formation of silicides and carbon was first observed above $650^{\circ}C$. At $750^{\circ}C$, as the reaction proceeded, the initially, formed $Ni_3Si_2$ layer was converted to $Ni_2$Si. The thin nickel film reacted completely with SiC after annealing at $950^{\circ}C$ for 2 h. The thermodynamically stable $Ni_2$Si is the only obsrved silicide in the reaction zone up to $1050^{\circ}C$. The formation of $Ni_2$Si layers with carbon precipitates alternated periodically with the carbon free layers. At temperatures between $950^{\circ}C$ and $1050^{\circ}C$, the typical layer sequences in the reaction zone is determined by quantitative microanalysis to be $SiC/Ni_2$$Si+C/Ni_2$$Si/Ni_2$$Si+C/…Ni_2$Si/Ni(Si)/Ni. The mechanism of the periodic band structure formation with the carbon precipitation behaviour was discussed in terms of reaction kinetics and thermodynamic considerations. The reaction kinetics is proposed to estimate the effective reaction constant from the parabolic growth of the reaction zone.

• Macromolecular Research
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• v.14 no.5
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• pp.504-509
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• 2006

Poly(vinyl phosphate-b-styrene) (PVPP-b-PS) block copolymers were synthesized successfully from poly(vinyl alcohol-b-styrene) (PVA-b-PS) by reaction with phosphorus oxychloride and subsequent hydrolysis. The obtained block copolymers were slightly crosslinked, and were characterized by various analytical techniques. The total phosphorus content and the ratio of the differently bound phosphorus were obtained by both solid-state $^{31}P$ NMR and pH titration, but the results differed slightly. Characterization by energy dispersion X-ray analysis (EDS) or Rutherford back scattering (RBS), on the other hand, determined the total phosphorus contents, but the results were quite different from those by solid-state $^{31}P$ NMR.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.47.2-47.2
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• 2007

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.154-154
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• 1992

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2001.04a
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• pp.167-172
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• 2001

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1994.10b
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• pp.16-16
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• 1994

• Proceedings of the Korean Vacuum Society Conference
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• 1992.07a
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• pp.38-38
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• 1992

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.509-516
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• 2020

An important property of glass and ceramic solid waste forms is processability. Tellurite materials with low melting temperatures and high halite solubilities have potential as solid waste forms. Crystalline TiTe3O8 was synthesized through a solid-state reaction between stoichiometric amounts of TiO2 and TeO2 powder. The resultant TiTe3O8 crystal had a three-dimensional (3D) structure consisting of TiO6 octahedra and asymmetric TeO4 seesaw moiety groups. The melting temperature of the TiTe3O8 powder was 820℃, and the constituent TeO2 began to evaporate selectively from TiTe3O8 above around 840℃. The leaching rate, as determined using the modified American Society of Testing and Materials static leach test method, of Ti in the TiTe3O8 crystal was less than the order of 10-4 g·m-2·d-1 at 90℃ for durations of 14 d over a pH range of 2-12. The chemical durability of the TiTe3O8 crystal, even under highly acidic and alkaline conditions, was comparable to that of other well-known Ti-based solid waste forms.