• Journal of the Korean Ceramic Society
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• v.24 no.4
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• pp.397-403
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• 1987

Pb(Zr0.52Ti0.48)O3 powders were prepared by hydrothermal synthesis. Using soluble salts such as Pb(NO3)2, TiCl4 and ZrOCl2$.$8H2O and oxide such as PbO and TiO2 as starting materials, PZT powder was hydrothermally synthesized at the temperature range between 150$^{\circ}C$ and 200$^{\circ}C$. The result showed that reactivity by alkali was decreased in the sequence of Pb(NO3)2, TiCl4, ZrOCl2, PbO, TiO2 and ZrO2. Using the first three soluble salts, PZT powder was synthesiged at 150$^{\circ}C$ for 1hr. In PbO-TiCl4-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 8rs. In Pb(NO3)2-TiO2-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 16hrs, in PbO-TiO2-ZrOCl2 system, the powder was synthesized at 200$^{\circ}C$ for 8hrs.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.853-857
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• 1995

ZrSiO4 powders were prepared from partially hydrolyzed solution of Si(OC2H5)4 and ZrOCl2.8H2O solution by the sol-gel method and formation rate of ZrSiO4 on the reaction parameter was investigated. In order to prepare homogeneous ZrSiO4 precursor gels, the H2O/Si(OC2H5)4 molar ratio of about 2, the pH of the ZrOCl2.8H2O solution fo about 4 and stirring time of the mixed solutions of about 2 hrs were appropriate. Formation of temperature of ZrSiO4 reduced about 15$0^{\circ}C$ by milling and formation of ZrSiO4 at 1300~135$0^{\circ}C$ showed an accelerative increase through the hedvall effect by silica.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.466-471
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• 2014

Hydrous zirconia particles were prepared from $ZrOCl_2$ aqueous solution using an electro-dialysis [ED] process. For the preparation of $(Zr,Y)(OH)_4$ precipitates, 3 mol% $YCl_3$ was added into $ZrOCl_2$ aqueous solution. During the hydrolysis of 0.5 mol/L $(Zr,Y)OCl_2$ solution at $90^{\circ}C$ a slurry solution was obtained. The ED process was used for the removal of chlorine from the slurry solution. Two kinds of slurry solution were sampled at the beginning and end of the ED process. The morphology of hydrous zirconia particles in the solution was observed using an inverted optical microscope and an FE-SEM. The hydrous zirconia particles were nano-crystalline, and easily coagulated with drying. Yttrium stabilized zirconia [YSZ] powder could be obtained by the calcination of $(Zr,Y)(OH)_4$ precipitates prepared from a $(Zr,Y)OCl_2$ solution by the ED process. The coagulated dry powders were shaped and sintered at $1500^{\circ}C$ for 2 h. The sintered body showed a dense microstructure with uniform grain morphology.

• Journal of the Korean Ceramic Society
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• v.37 no.5
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• pp.497-504
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• 2000

In this study, mullite-zirconia comosite was fabricated by adding ZrOCl2.8H2O using of boehmite gel coating to Hadong kaolin (pink A grade) in order to enhance strength of the mullite specimens. The influence of ZrOCl2.8H2O content and fireing temperature on the crystall phase, microstructure, bulk density, strength of the specimens was investigated. Mullite-zirconia composite was produced in the process of coating zirconia to mullite powder synthesized thereafter and mixing simultaneously of starting materials with boehmite-zirconia gel. Maximum strength with in this study was 251 sintered at 1$600^{\circ}C$ for 2h. Bulk density and strength of the composite with zirconia coated mullite was higher than simultaneous on mixture of starting materials.

• Journal of the Korean Chemical Society
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• v.57 no.4
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• pp.472-475
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• 2013

An efficient and environmentally benign protocol for the three-component synthesis of triazoloindazoles and indazolophthalazines via condensation of dimedone, aldehydes and urazole or phthalhydrazide catalyzed by $ZrOCl_2.8H_2O$ as an inexpensive and eco-friendly catalyst with high catalytic activity under solvent-free conditions is reported. This protocol provides a new and improved method for obtaining triazoloindazoles and indazolophthalazines in terms of good yields, simple experimental procedure and short reaction time.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.6
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• pp.229-234
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• 2018

The glass-ceramic of $Li_2O-Al_2O_3-SiO_2$ system was synthesized by using $ZrO_2$, $ZrSiO_4$, $ZrOCl_2$ and $Zr(SO_4)_2$, which is a raw material of Zr serving as a nucleation agent. It was confirmed that Avrami parameter of these four glasses is over 3 for bulk crystallization. The glass synthesized by $ZrOCl_2$, and $Zr(SO_4)_2$ showed high melting quality during the melting process. It is also observed that the Zr component is uniformly distributed in the glass. Various characterizations was evaluated, including composition analysis and bending strength.

• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.186-192
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• 1987

ZrO2 powders having high purity were prepared from domestic zircon sand using the caustic fusion method and the soda ash sintering process. In the caustic fusion method, ZrO2 recovery was reached to 96% when 100/140 mesh zircon was reacted with NaOH at the NaOH/Zircon mole ratio 6 and at 650$^{\circ}C$ for 2 hours. And in the soda ash sintering process, ZrO2 was recovered to 88.5% when -325 mesh zircon was reacted with Na2CO3 at the Na2CO3/Zircon mole ratio 1.1 and 1050$^{\circ}C$ for 2 hours. In both cases, Zr component was extracted to ZrOCl2, subsequently crystallized to ZrOCl2$.$8H2O to increase the purity, and converted to ZrO2 by precipitation. And to increase the sinter ability of powder, Cl- ion was removed and strong agglomeration was avoided by methanol distribution of Zr(OH)4 precipitates.

• Particle and aerosol research
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• v.4 no.1
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• pp.21-25
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• 2008

$Pb(Zr_{0.53}Ti_{0.47})O_3$ (PZT) was synthesized by a multiple wet dry process. Precipitates prepared from reaction between $ZrOCl_2{\cdot}8H_2O$ and $TiOCl_2$ and $NH_4OH$ in an aqueous solution was dried at $100^{\circ}C$, and calcined at $500^{\circ}C$ and $700^{\circ}C$. The mixture mixed with PbO and as-dried or calcined $Zr_{0.53}Ti_{0.47}O_4$ (ZT) powders was calcined again at 700 and $800^{\circ}C$. Well crystallized ZT and PZT were formed at even $700^{\circ}C$. PZT piezoelectric ceramics of more than 98.5% in a relative density was obtained by sintering at as low as $900^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.361-368
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• 1990

The properties of the powder of ZrO2＋3m/o Y2O3 system prepared by co-precipitation method at the pH values of 7, 9, 10 and 11 were investigated. ZrOCl2.8H2O and YCl3.6H2O were used as starting materials and NH4OH as a precipitation agent. Zirconium hydroxide near by Zr(OH)4 structure showed more excellent crystallinity and lower formation temperature of tetragonal ZrO2. In the range of this study, cubic ZrO2 was not formed and stability of tetragonal ZrO2 prepared in the conditiion of pH 7 was most excellent. Average particle sizes and specific surface areas of tetragonal ZrO2 powders, prepared as calcining amorphous zirconium hydroxides at $600^{\circ}C$ for 1h, were 0.6-0.8${\mu}{\textrm}{m}$ and 45-70$m^2$/g, respectively.

• Journal of the Korean Ceramic Society
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• v.23 no.3
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• pp.44-52
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• 1986

$Al_2O_3-ZrO_2$ ceramics was obtained by the co-precipitation method using $Al_2(SO_4)_2$.$18H_2O$ and $ZrOCl_2$.$8H_2O$ as starting materials $MgCl_2$.$6H_2O$ as a sintering aid and NH4OH as a hydrolyzing agent. The coprecipitate from the above raw materials was calcined at 125$0^{\circ}C$ for 1h and again sintered at 1$650^{\circ}C$ for 2h before measurements of strength hardness and fracture toughness. MgO addition was found to increase mechanical properties of the $Al_2O_3-ZrO_2$ system. The strength and frac-ture toughness of $Al_2O_3-ZrO_2$ ceramics were considered to be increased by stress-induced phase tranforma-tion of $ZrO_2$.