• Korean Journal of Crystallography
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• v.8 no.2
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• pp.97-104
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• 1997

Hydrothermal synthesis of PbZ1-xTixO3 has been investigated. Syntheses were performed using lead acetate triphdrate as Pb source, Ti/Zr gel by hydrolizing Ti-isopropoxide as Tiand Zr source and Zr-propoxide and KOH (0.5m, 1m, 2m) as mineralizer. The hydrothermal synthesis has been examined at 140℃, 150℃ and 160℃. Synthesized PZT powders showed a rectangular shape and were agglomerate. At 1m and 2m KOH concentrations PZT powders were synthesized the respective time of 8 hrs and 1hr but at 0.5m KOH concentration phase pure PZT powders were not synthesized for 5days reaction. At the conditions of low temperature and low KOH concentration unreacted Ti/Zr gel remained although synthesized powders were almost PZT. The size of PZT powders increased with KOH concentrations. PbO solid solutions were formed as intermediate phases and these were classified to PbO-10%TiO2 solid solution and PbO-3% TiO-3% TiO2 solid solution.

• Korean Journal of Crystallography
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• v.8 no.1
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• pp.15-19
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• 1997

Single crystals of Co-doped quartz (blue quartz) were grown hydrothermally from the $Na_2CO_3$ solution. The size of as-grown crystal was $100{\times}50{\times}35mm^3$ and the growth rate was 0.55 mm/day under the growth condition of $5wt.\%\;Na_2CO_3$ mineralizer, growth temperature of $343^{\circ}C$ and temperature gradient of $22^{\circ}C$. Visible spectrum showed a typical absorption feature of the synthetic blue quartz near 545, 570 and 643 nm. The concentration of color of the as-grown blue quartz related not to the concentration of cobalt in raw material but to the growth temperature.

• Korean Journal of Crystallography
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• v.8 no.1
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• pp.26-32
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• 1997

Quartz single crystals were grown hydrothermally and growth defects such as dislocations, etch channels and impurities were examined. Growth rates were 0.25-0.65 mm/day under the growth conditions of following. 1. Mineralizer: $4wt.\%$ NaOH. 2. Growth temperature: $340-360^{\circ}C$. 3. Temperature gradient: $20-40^{\circ}C$. 4. Seed: ZY plate. 5. Nutrient: synthetic quartz. Defects of the quartz which was grown with optical grade synthetic nutrient, low dislocation density seed and horizontal seed setting technique were as follows. 1. Dislocation density: 20.0 each/$cm^2$. 2. Etch channel density: 5.0 each/$cm^2$ (1st grade by IEC 758 standard). 3. Impurity (larger than 10$\mu$) concentration: 2.4 each/$cm^3$ (Ia grade by IEC 758 standard). 4. Alpha value: 0.019 (A grade by IEC 758 standard).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.4
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• pp.169-175
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• 2014

Digital ink-jet printing system has many advantages such as fast and fine printing of various images, high efficiency and low cost process. Generally digital ink-jet printing requires ceramic pigments of cyan, magenta, yellow and black with thermal and glaze stability above $1000^{\circ}C$ for the application of porcelain product design. In this study, pink-red colored $CaO-SnO_2-Cr_2O_3-SiO_2$ pigment was synthesized using solid state reaction. The synthesis conditions of $Ca(Cr,Sn)SiO_5$ pigment such as annealing temperature, amount of mineralizer and non-stoichiometric composition were optimized. Crystal structure and morphology of the obtained $Ca(Cr,Sn)SiO_5$ pigment were analyzed using XRD, SEM, PSA, FT-IR and effect of Cr substitution on the pigment color was analyzed using Uv-vis. spectrophotometer and CIE $L^*a^*b^*$ measurement.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.4
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• pp.328-334
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• 2014

This study reviewed the usability of sludge, a material that is additionally created when polysilicon (a solar light material) is produced, as the raw material for cement clinker. It was evaluated that when cement clinker is produced, the chloric component of polysilicon acted as a mineralizer in the firing process. In addition, the physical features of the produced cement were measured. The setting time of the produced cement was reduced as the amount of content of polysilicon sludge increased. Such results were drawn because the chloric component acted as hydration accelerator and enhanced the dissolution of calcium hydroxide that was formed by hydration of $C_3S$. Furthermore, for such reason, on the day 1, the compression strength of mortar increased as the content of polysilicon sludge increased. In day 3, 7, and 28, the tendency in which the compression strength increasing up to 5% of the amount of added polysilicon sludge was shown. It is because when clinker was produced, the chloric component increased the amount of $C_3S$ mineral created, thus enhancing the compression strength after day 3.