• Journal of the Korean Ceramic Society
• /
• v.38 no.9
• /
• pp.860-865
• /
• 2001

After manufacturing 2mol% CdO substitute $0.05Pb(Mn_{1/3}Sb_{2/3})O_3-0.95Pb(Zr_{0.52}Ti_{0.48})O_3$ piezoelectric ceramics powder as starting material, to manufacture green sheets using Doctor Blade method. The optimum composition of slurry was studied. Moreover, the sintering properties and the dielectric and piezoelectric properties with variation a thickness of the manufactured sheets were investigated. The optimum of slurry was investigated by the rheology with addition of additives, the sintering condition was decided by TGA. And the properties of sheet were investigated through SEM. XRD. The optimum of slurry was the stablest at dispersant 3.0 wt% to solid loading 30vol%. After, at addition of binder/plasticizer(0.75/0.25) 3.0wt%, viscosity was 7.55Pa${\cdot}$s. The dielectric and piezoelectric properties of the sheet were increased a little with the increasing of sintering temperature but were not variable with variation of sheet thickness.

• Proceedings of the KIEE Conference
• /
• 1995.11a
• /
• pp.345-347
• /
• 1995

ZnO varistor with composition of ZnO(90wt%)-$Bi_2O_3$(3wt%)-$Sb_2O_3$(3.61wt%)-$CO_2O_3$(1.16wt%)-NiO (0.88wt%)-$MnO_2$(0.71wt%)-$Cr_2O_3$(0.93wt%) according to $Al_2O_3$ addtive was fabricated by sintering methods. The optimal densification were established for the processing conditions of 8000 rpm 190$^{\circ}C$ spray drying and 1200$^{\circ}C$ 2hrs sintering. Then here investigated how additive compotions and processing variables affected the electrical and the phesical properties of these ZnO varistors.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.3
• /
• pp.418-427
• /
• 1997

The effect of $La_2O_3$ as a dopant on the microstructure structure, crystal structure and electrical properties was studied. $0.05Pb(Sn_{0.5}Sb_{0.5})O_3＋0.11PbTiO_3＋0.84PbZroO_3＋0.4Wt%MnO_2$ (=0.05PSS ＋0.11PT＋0.84PZ+0.4wt%$MnO_2$) systems doped with 0, 0.1, 0.3, 0.5, 0.7, 1, 3, 5 mole% $La_2O_3$ were fabricated and investigated sintering density, crystal structure and micro-structure. The sintered 0.05PSS＋0.11PT＋0.84PZ+0.4wt%$MnO_2$ system doped with $La_2O_3$showed sintering density of the range of 7.683 g/㎤ of 0 mole% doping to 7.815 g/㎤ of 0 mole% doping. The average grain sizes in the range of 0 to 5 mole% $La_2O_3$were decreased from 9.0 $\mu\textrm{m}$ to 1.3 $\mu\textrm{m}$. X-ray diffraction investigation of sintered bodies showed that solid solutions were formed between 0.05PSS＋0.11PT＋0.84PZ+0.4wt%$MnO_2$ system and $La_2O_3$ in the range of 0 to 1 mole% but second phases were formed in case of 3, 5 mole%. Dielectric constants at 1 kHz were increased with 0 to 3 mlole% $La_2O_3$ before and after poling at the condition of 5 $KV_{DC}$/mm at $120^{\circ}C$ or $140^{\circ}C$ during 20 minutes. All Dielectric losses at 1 kHz were less than 1%, Curie temperatures were $208^{\circ}C$, $183^{\circ}C$, $152^{\circ}C$ and $127^{\circ}C$ at 0, 0.5, 1, 3 mole% $La_2O_3$ respectively. The values of $K_p$ were increased from 0 to 3 mole% $La_2O_3$ after poling at condition of 5 $KV_{DC}$mm at the condition of $120^{\circ}C$ or $140^{\circ}C$. The case of 0.7 mole% $La_2O_3$doped 0.05PSS＋0.11PT＋0.84PZ+0.4wt%$MnO_2$ system showed $K_p$ of 14.5% by poling at $140^{\circ}C$ during 20 minutes.

• Proceedings of the KIEE Conference
• /
• 2003.10a
• /
• pp.107-109
• /
• 2003

This paper was to measure the structure, piezoelectric properties of $0.03Pb(Mg_{0.5}W_{0.5})O_3$ - $0.12Pb(Sb_{0.5}Nb_{0.5})O_3$ - $0.85Pb(Zr_{0.52}Ti_{0.48})O_3$ + $0.5[wt%]MnO_2$ ceramics dropped with additive CuO after manufacturing the specimens with a general method. It is shown that X-ray diffraction pattern variation of lines (211) have tendency to move minutely by addition of additive CuO. According to dropping with Cu, the dielectric constant at 20[$^{\circ}C$] reduced to CuO 3.0[wt%]. In case of sintering at 1050[$^{\circ}C$], dielectric constant was maximum value 623.59 at CuO 1.0[wt%]. Dielectric loss was maximum value 2.7[%] at Cu 2.0[wt%] in case of sintering at 1050[$^{\circ}C$].

• Fire Science and Engineering
• /
• v.16 no.4
• /
• pp.65-71
• /
• 2002

In this paper, the thermal and flame properties of GFRP with various flame retardant(aluminum trihydrate, antimony trioxide) compositions have been investigated by thermal analysis and flammability tests(LOI test, flammability 45 degree test). The flame and mechanical properties(hardness, tensile strength, modulus) of general purpose grade glass fiber/unsaturated polyester composite with flame retardant composition have been also evaluated. The effect of cure pressure on the flame properties of aerospace grade glass fiber/epoxy composite was investigated. Considering the flame and mechanical property of composite, we could determine the optimum flame retardant composition(ATH 10∼20 phr). Test results show that the flame property of glass fiber/epoxy composite is considerably affected by cure pressure conditions.