• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.7
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• pp.404-407
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• 2016

In this study, to develop low temperature sintering capacitor composition ceramics with the good dielectric properties, $(Ba_{0.86}Ca_{0.14})(Ti_{0.85}Zr_{0.12}Sn_{0.03})O_3$ (BCTZ) ceramics were prepared by the conventional solid-state reaction method. The effects of $B_2O_3$ addition on the dielectric properties and microstructure was investigated. The XRD patterns demonstrated that all the specimens showed Perovskite phase, and secondary phases are indicated in the measurement range of XRD. And also, temperature coefficient of capacitance(TCC) of all the specimen sintered at $1,180^{\circ}C$ showed +3~-56% except for x=0.006. For all the specimens, observed one peak was tetragonal cubic difuse phase transition temperature(Tc), which is located in the vicinity of room temperature.

• Journal of Powder Materials
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• v.11 no.5
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• pp.421-426
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• 2004

The microstructure and mechanical property of hot-pressed $Al_2O_3/Cu$ composites with a different temperature for atmosphere changing from H$_{2}$ to Ar have been studied. When atmosphere-changed from H$_{2}$ to Ar gas at 145$0^{\circ}C$, the hot-pressed composite was characterized by inhomogeneous microstructure and low fracture strength. On the contrary, when atmosphere-changed at low temperature of 110$0^{\circ}C$ the composite showed more homogeneous microstructure, higher fracture strength and smaller deviation in strength. Based on the thermodynamic consideration and microstructural analysis, it was interpreted that the Cu wetting behavior relating to the formation of CuAlO$_{2}$ is probably responsible for strong dependence of microstructure on atmosphere changing temperature. The reason for a strong sensitivity of fracture strength and especially of its deviation to atmosphere changing temperature was explained by the microstructural inhomogeneity and by the role of CuAlO$_{2}$ phase on the interfacial bonding strength.

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.563-571
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• 1996

In order to fabricate solid electrolyte CaO-stabilized ZrO2 of high density sintered body economically 13 mol% CaO-stabilized ZrO2 powders were synthesized by the coprecipitation method. The characteristics and sintering behavior of fine powder were investigated. The precipitates has the specific surface area of 193 m2/g and apperaed to be fine and spherical primary particles with a size of approximately 5nm. The crystalliza-tion temperture of CaO-stabilized ZrO2 was 462$^{\circ}C$. The tetragonal phase was stable in the low calcining tempe-rature regions and the cubic zirconia solid solution was formed from above 120$0^{\circ}C$ through an intermediate stage of formation of CaZrO3 By introducing fine powders washed with alcohol and ball-milling process after calcination the sintered body was possible to attain the value of above 92% of the theoretical density at low temperature of 120$0^{\circ}C$.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.119-119
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• 2000

A new type of low voltage driven SrTiO3 varistor was investigated. $SrTi3_3$ sintered with CuO-SiO2 additions, the sintering temperature was reduced to 1250-1300C. With the sintering additives, the semiconducting SrTi03 was able to fabricate single time sintering in reducing atmosphere(95% N2 + 5% H2), The non-linear coefficient value was 10.3 and the operating voltage was about 7 V.

• Journal of the Korean Ceramic Society
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• v.30 no.10
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• pp.845-851
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• 1993

Low firing temperature substrate were synthesized through tape casting and sintering of glass with cordierite composition and then their properties were investigated. Even though the dielectric properties and XRD patterns of substrates, obtained by tape casting and sintering at 900~100$0^{\circ}C$ for various periods, were similar to those of substrates obtained by dry pressing, the sinterability was enhanced. The substrates were thin and the size was 0.6$\times$50$\times$50mm. From the results of dielectric properties, the sinterability and X-ray diffraction pattern, the proper condition for cofiring process with conductor, Cu, was 90$0^{\circ}C$ for 1h. The properties of the substrate are as follows; the dielectric constant was 5.31(at 1MHz), the dissipation factor was 0.0028, the apparent porosity was 0.28% and the main crystalline phase was $\alpha$-cordierite.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.25-34
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• 2001

There are many kinds of dielectric materials in microwave dielectric filters for mobile telecomunication. But It is need to new dielectric materials for IMT200O, Bluetooth, wireless LAN to miniaturize the dielectric filters. These kinds of materials should have high dielectric constants, high Q, and low firing sintering temperature(<900˚C ). Multilayer monolithic dielectric filters are manufactured by BiNb04, dielectric ceramics cofired at 875˚C .

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.701-704
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• 2003

In this study, to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, PSN-PNN-PZT system ceramics were manufactured as a function of CuO addition. Its dielectric and piezoelectric characteristics were investigated. With increasing the amount of CuO addition, grain size was increased and density increased until 0.3wt% CuO. Taking into consideration electromechanical coupling factor(kp) of 0.53, mechanical quality factor(Qm) of 423 and ${\epsilon}r$ of 1759, it can be cincluded that the CuO 0.5wt% added composition sintered at $920^{\circ}C$ is suitable for piezoelectric transformer application if Qm is improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.656-659
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• 2003

In this study, in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, dielectric and piezoelectric properties of PSN-PZT ceramics were investigated according to Zr/Ti ratio. As Zr/Ti ratio is increased, coupling factor(kp) and dielectric constant were increased and then decreased after the ratio of Zr/Ti=50/50. And also, mechanical quality factor were decreased and then increased after the ratio of Zr/Ti=50/50.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.256-259
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• 1999

The purpose of this study is to develop the material for multiayer piezoelectric ceramic transformer because multiayer piezoelectric transformer must need low sintering temperature. So that PMN-PSN-PZT family ceramics were added with glass brit(SiO$_2$ $.$ PbO). The dielectric and piezoelectric properties were increased with increasing it until the amounts of additive 0.8wt%. Sintering temperature were low about 100[$^{\circ}C$]. Accordingly, This material could be used to multiayer piezoelectric transformer .

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.232-235
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• 2003

In this study, in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, dielectric and piezoelectric properties of PSN-PZT ceramics were investigated as a function of CuO addition, At the 0.6wt% CuO added specimen sintered at $920^{\circ}C$, the most excellent mechanical quality factor and electromechanical coupling factor were obtained.